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Table of contents

- Crypto
  - Determining if crypto support is unavailable
  - Class: `Certificate`
    - Static method: `Certificate.exportChallenge(spkac[, encoding])`
    - Static method: `Certificate.exportPublicKey(spkac[, encoding])`
    - Static method: `Certificate.verifySpkac(spkac[, encoding])`
    - Legacy API
      - `new crypto.Certificate()`
      - `certificate.exportChallenge(spkac[, encoding])`
      - `certificate.exportPublicKey(spkac[, encoding])`
      - `certificate.verifySpkac(spkac[, encoding])`
  - Class: `Cipher`
    - `cipher.final([outputEncoding])`
    - `cipher.getAuthTag()`
    - `cipher.setAAD(buffer[, options])`
    - `cipher.setAutoPadding([autoPadding])`
    - `cipher.update(data[, inputEncoding][, outputEncoding])`
  - Class: `Decipher`
    - `decipher.final([outputEncoding])`
    - `decipher.setAAD(buffer[, options])`
    - `decipher.setAuthTag(buffer[, encoding])`
    - `decipher.setAutoPadding([autoPadding])`
    - `decipher.update(data[, inputEncoding][, outputEncoding])`
  - Class: `DiffieHellman`
    - `diffieHellman.computeSecret(otherPublicKey[, inputEncoding][, outputEncoding])`
    - `diffieHellman.generateKeys([encoding])`
    - `diffieHellman.getGenerator([encoding])`
    - `diffieHellman.getPrime([encoding])`
    - `diffieHellman.getPrivateKey([encoding])`
    - `diffieHellman.getPublicKey([encoding])`
    - `diffieHellman.setPrivateKey(privateKey[, encoding])`
    - `diffieHellman.setPublicKey(publicKey[, encoding])`
    - `diffieHellman.verifyError`
  - Class: `DiffieHellmanGroup`
  - Class: `ECDH`
    - Static method: `ECDH.convertKey(key, curve[, inputEncoding[, outputEncoding[, format]]])`
    - `ecdh.computeSecret(otherPublicKey[, inputEncoding][, outputEncoding])`
    - `ecdh.generateKeys([encoding[, format]])`
    - `ecdh.getPrivateKey([encoding])`
    - `ecdh.getPublicKey([encoding][, format])`
    - `ecdh.setPrivateKey(privateKey[, encoding])`
    - `ecdh.setPublicKey(publicKey[, encoding])`
  - Class: `Hash`
    - `hash.copy([options])`
    - `hash.digest([encoding])`
    - `hash.update(data[, inputEncoding])`
  - Class: `Hmac`
    - `hmac.digest([encoding])`
    - `hmac.update(data[, inputEncoding])`
  - Class: `KeyObject`
    - Static method: `KeyObject.from(key)`
    - `keyObject.asymmetricKeyDetails`
    - `keyObject.asymmetricKeyType`
    - `keyObject.export([options])`
    - `keyObject.equals(otherKeyObject)`
    - `keyObject.symmetricKeySize`
    - `keyObject.type`
  - Class: `Sign`
    - `sign.sign(privateKey[, outputEncoding])`
    - `sign.update(data[, inputEncoding])`
  - Class: `Verify`
    - `verify.update(data[, inputEncoding])`
    - `verify.verify(object, signature[, signatureEncoding])`
  - Class: `X509Certificate`
    - `new X509Certificate(buffer)`
    - `x509.ca`
    - `x509.checkEmail(email[, options])`
    - `x509.checkHost(name[, options])`
    - `x509.checkIP(ip)`
    - `x509.checkIssued(otherCert)`
    - `x509.checkPrivateKey(privateKey)`
    - `x509.fingerprint`
    - `x509.fingerprint256`
    - `x509.fingerprint512`
    - `x509.infoAccess`
    - `x509.issuer`
    - `x509.issuerCertificate`
    - `x509.keyUsage`
    - `x509.publicKey`
    - `x509.raw`
    - `x509.serialNumber`
    - `x509.subject`
    - `x509.subjectAltName`
    - `x509.toJSON()`
    - `x509.toLegacyObject()`
    - `x509.toString()`
    - `x509.validFrom`
    - `x509.validTo`
    - `x509.verify(publicKey)`
  - `node:crypto` module methods and properties
    - `crypto.constants`
    - `crypto.DEFAULT_ENCODING`
    - `crypto.fips`
    - `crypto.checkPrime(candidate[, options[, callback]])`
    - `crypto.checkPrimeSync(candidate[, options])`
    - `crypto.createCipher(algorithm, password[, options])`
    - `crypto.createCipheriv(algorithm, key, iv[, options])`
    - `crypto.createDecipher(algorithm, password[, options])`
    - `crypto.createDecipheriv(algorithm, key, iv[, options])`
    - `crypto.createDiffieHellman(prime[, primeEncoding][, generator][, generatorEncoding])`
    - `crypto.createDiffieHellman(primeLength[, generator])`
    - `crypto.createDiffieHellmanGroup(name)`
    - `crypto.createECDH(curveName)`
    - `crypto.createHash(algorithm[, options])`
    - `crypto.createHmac(algorithm, key[, options])`
    - `crypto.createPrivateKey(key)`
    - `crypto.createPublicKey(key)`
    - `crypto.createSecretKey(key[, encoding])`
    - `crypto.createSign(algorithm[, options])`
    - `crypto.createVerify(algorithm[, options])`
    - `crypto.diffieHellman(options)`
    - `crypto.generateKey(type, options, callback)`
    - `crypto.generateKeyPair(type, options, callback)`
    - `crypto.generateKeyPairSync(type, options)`
    - `crypto.generateKeySync(type, options)`
    - `crypto.generatePrime(size[, options[, callback]])`
    - `crypto.generatePrimeSync(size[, options])`
    - `crypto.getCipherInfo(nameOrNid[, options])`
    - `crypto.getCiphers()`
    - `crypto.getCurves()`
    - `crypto.getDiffieHellman(groupName)`
    - `crypto.getFips()`
    - `crypto.getHashes()`
    - `crypto.getRandomValues(typedArray)`
    - `crypto.hkdf(digest, ikm, salt, info, keylen, callback)`
    - `crypto.hkdfSync(digest, ikm, salt, info, keylen)`
    - `crypto.pbkdf2(password, salt, iterations, keylen, digest, callback)`
    - `crypto.pbkdf2Sync(password, salt, iterations, keylen, digest)`
    - `crypto.privateDecrypt(privateKey, buffer)`
    - `crypto.privateEncrypt(privateKey, buffer)`
    - `crypto.publicDecrypt(key, buffer)`
    - `crypto.publicEncrypt(key, buffer)`
    - `crypto.randomBytes(size[, callback])`
    - `crypto.randomFillSync(buffer[, offset][, size])`
    - `crypto.randomFill(buffer[, offset][, size], callback)`
    - `crypto.randomInt([min, ]max[, callback])`
    - `crypto.randomUUID([options])`
    - `crypto.scrypt(password, salt, keylen[, options], callback)`
    - `crypto.scryptSync(password, salt, keylen[, options])`
    - `crypto.secureHeapUsed()`
    - `crypto.setEngine(engine[, flags])`
    - `crypto.setFips(bool)`
    - `crypto.sign(algorithm, data, key[, callback])`
    - `crypto.subtle`
    - `crypto.timingSafeEqual(a, b)`
    - `crypto.verify(algorithm, data, key, signature[, callback])`
    - `crypto.webcrypto`
  - Notes
    - Using strings as inputs to cryptographic APIs
    - Legacy streams API (prior to Node.js 0.10)
    - Support for weak or compromised algorithms
    - CCM mode
  - Crypto constants
    - OpenSSL options
    - OpenSSL engine constants
    - Other OpenSSL constants
    - Node.js crypto constants

## Crypto#

Stability: 2 - Stable

Source Code: lib/crypto.js

The `node:crypto` module provides cryptographic functionality that includes a set of wrappers for OpenSSL's hash, HMAC, cipher, decipher, sign, and verify functions.

    const { createHmac } = await import('node:crypto');

    const secret = 'abcdefg';
    const hash = createHmac('sha256', secret)
                   .update('I love cupcakes')
                   .digest('hex');
    console.log(hash);
    // Prints:
    //   c0fa1bc00531bd78ef38c628449c5102aeabd49b5dc3a2a516ea6ea959d6658econst crypto = require('node:crypto');

    const secret = 'abcdefg';
    const hash = crypto.createHmac('sha256', secret)
                       .update('I love cupcakes')
                       .digest('hex');
    console.log(hash);
    // Prints:
    //   c0fa1bc00531bd78ef38c628449c5102aeabd49b5dc3a2a516ea6ea959d6658e

### Determining if crypto support is unavailable#

It is possible for Node.js to be built without including support for the `node:crypto` module. In such cases, attempting to `import` from `crypto` or calling `require('node:crypto')` will result in an error being thrown.

When using CommonJS, the error thrown can be caught using try/catch:

    let crypto;
    try {
      crypto = require('node:crypto');
    } catch (err) {
      console.log('crypto support is disabled!');
    }

When using the lexical ESM `import` keyword, the error can only be caught if a handler for `process.on('uncaughtException')` is registered before any attempt to load the module is made (using, for instance, a preload module).

When using ESM, if there is a chance that the code may be run on a build of Node.js where crypto support is not enabled, consider using the `import()` function instead of the lexical `import` keyword:

    let crypto;
    try {
      crypto = await import('node:crypto');
    } catch (err) {
      console.log('crypto support is disabled!');
    }

### Class: `Certificate`#

Added in: v0.11.8

SPKAC is a Certificate Signing Request mechanism originally implemented by Netscape and was specified formally as part of HTML5's `keygen` element.

`<keygen>` is deprecated since HTML 5.2 and new projects should not use this element anymore.

The `node:crypto` module provides the `Certificate` class for working with SPKAC data. The most common usage is handling output generated by the HTML5 `<keygen>` element. Node.js uses OpenSSL's SPKAC implementation internally.

#### Static method: `Certificate.exportChallenge(spkac[, encoding])`#

History

Version | Changes
--- | ---
v15.0.0 | The spkac argument can be an ArrayBuffer. Limited the size of the spkac argument to a maximum of 2**31 - 1 bytes.
v9.0.0 | Added in: v9.0.0

- `spkac` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The encoding of the `spkac` string.
- Returns: <Buffer> The challenge component of the `spkac` data structure, which includes a public key and a challenge.

    const { Certificate } = await import('node:crypto');
    const spkac = getSpkacSomehow();
    const challenge = Certificate.exportChallenge(spkac);
    console.log(challenge.toString('utf8'));
    // Prints: the challenge as a UTF8 stringconst { Certificate } = require('node:crypto');
    const spkac = getSpkacSomehow();
    const challenge = Certificate.exportChallenge(spkac);
    console.log(challenge.toString('utf8'));
    // Prints: the challenge as a UTF8 string

#### Static method: `Certificate.exportPublicKey(spkac[, encoding])`#

History

Version | Changes
--- | ---
v15.0.0 | The spkac argument can be an ArrayBuffer. Limited the size of the spkac argument to a maximum of 2**31 - 1 bytes.
v9.0.0 | Added in: v9.0.0

- `spkac` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The encoding of the `spkac` string.
- Returns: <Buffer> The public key component of the `spkac` data structure, which includes a public key and a challenge.

    const { Certificate } = await import('node:crypto');
    const spkac = getSpkacSomehow();
    const publicKey = Certificate.exportPublicKey(spkac);
    console.log(publicKey);
    // Prints: the public key as <Buffer ...>const { Certificate } = require('node:crypto');
    const spkac = getSpkacSomehow();
    const publicKey = Certificate.exportPublicKey(spkac);
    console.log(publicKey);
    // Prints: the public key as <Buffer ...>

#### Static method: `Certificate.verifySpkac(spkac[, encoding])`#

History

Version | Changes
--- | ---
v15.0.0 | The spkac argument can be an ArrayBuffer. Added encoding. Limited the size of the spkac argument to a maximum of 2**31 - 1 bytes.
v9.0.0 | Added in: v9.0.0

- `spkac` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The encoding of the `spkac` string.
- Returns: <boolean> `true` if the given `spkac` data structure is valid, `false` otherwise.

    import { Buffer } from 'node:buffer';
    const { Certificate } = await import('node:crypto');

    const spkac = getSpkacSomehow();
    console.log(Certificate.verifySpkac(Buffer.from(spkac)));
    // Prints: true or falseconst { Certificate } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    const spkac = getSpkacSomehow();
    console.log(Certificate.verifySpkac(Buffer.from(spkac)));
    // Prints: true or false

#### Legacy API#

Stability: 0 - Deprecated

As a legacy interface, it is possible to create new instances of the `crypto.Certificate` class as illustrated in the examples below.

##### `new crypto.Certificate()`#

Instances of the `Certificate` class can be created using the `new` keyword or by calling `crypto.Certificate()` as a function:

    const { Certificate } = await import('node:crypto');

    const cert1 = new Certificate();
    const cert2 = Certificate();const { Certificate } = require('node:crypto');

    const cert1 = new Certificate();
    const cert2 = Certificate();

##### `certificate.exportChallenge(spkac[, encoding])`#

Added in: v0.11.8

- `spkac` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The encoding of the `spkac` string.
- Returns: <Buffer> The challenge component of the `spkac` data structure, which includes a public key and a challenge.

    const { Certificate } = await import('node:crypto');
    const cert = Certificate();
    const spkac = getSpkacSomehow();
    const challenge = cert.exportChallenge(spkac);
    console.log(challenge.toString('utf8'));
    // Prints: the challenge as a UTF8 stringconst { Certificate } = require('node:crypto');
    const cert = Certificate();
    const spkac = getSpkacSomehow();
    const challenge = cert.exportChallenge(spkac);
    console.log(challenge.toString('utf8'));
    // Prints: the challenge as a UTF8 string

##### `certificate.exportPublicKey(spkac[, encoding])`#

Added in: v0.11.8

- `spkac` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The encoding of the `spkac` string.
- Returns: <Buffer> The public key component of the `spkac` data structure, which includes a public key and a challenge.

    const { Certificate } = await import('node:crypto');
    const cert = Certificate();
    const spkac = getSpkacSomehow();
    const publicKey = cert.exportPublicKey(spkac);
    console.log(publicKey);
    // Prints: the public key as <Buffer ...>const { Certificate } = require('node:crypto');
    const cert = Certificate();
    const spkac = getSpkacSomehow();
    const publicKey = cert.exportPublicKey(spkac);
    console.log(publicKey);
    // Prints: the public key as <Buffer ...>

##### `certificate.verifySpkac(spkac[, encoding])`#

Added in: v0.11.8

- `spkac` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The encoding of the `spkac` string.
- Returns: <boolean> `true` if the given `spkac` data structure is valid, `false` otherwise.

    import { Buffer } from 'node:buffer';
    const { Certificate } = await import('node:crypto');

    const cert = Certificate();
    const spkac = getSpkacSomehow();
    console.log(cert.verifySpkac(Buffer.from(spkac)));
    // Prints: true or falseconst { Certificate } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    const cert = Certificate();
    const spkac = getSpkacSomehow();
    console.log(cert.verifySpkac(Buffer.from(spkac)));
    // Prints: true or false

### Class: `Cipher`#

Added in: v0.1.94

- Extends: <stream.Transform>

Instances of the `Cipher` class are used to encrypt data. The class can be used in one of two ways:

- As a stream that is both readable and writable, where plain unencrypted data is written to produce encrypted data on the readable side, or
- Using the `cipher.update()` and `cipher.final()` methods to produce the encrypted data.

The `crypto.createCipher()` or `crypto.createCipheriv()` methods are used to create `Cipher` instances. `Cipher` objects are not to be created directly using the `new` keyword.

Example: Using `Cipher` objects as streams:

    const {
      scrypt,
      randomFill,
      createCipheriv
    } = await import('node:crypto');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';

    // First, we'll generate the key. The key length is dependent on the algorithm.
    // In this case for aes192, it is 24 bytes (192 bits).
    scrypt(password, 'salt', 24, (err, key) => {
      if (err) throw err;
      // Then, we'll generate a random initialization vector
      randomFill(new Uint8Array(16), (err, iv) => {
        if (err) throw err;

        // Once we have the key and iv, we can create and use the cipher...
        const cipher = createCipheriv(algorithm, key, iv);

        let encrypted = '';
        cipher.setEncoding('hex');

        cipher.on('data', (chunk) => encrypted += chunk);
        cipher.on('end', () => console.log(encrypted));

        cipher.write('some clear text data');
        cipher.end();
      });
    });const {
      scrypt,
      randomFill,
      createCipheriv
    } = require('node:crypto');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';

    // First, we'll generate the key. The key length is dependent on the algorithm.
    // In this case for aes192, it is 24 bytes (192 bits).
    scrypt(password, 'salt', 24, (err, key) => {
      if (err) throw err;
      // Then, we'll generate a random initialization vector
      randomFill(new Uint8Array(16), (err, iv) => {
        if (err) throw err;

        // Once we have the key and iv, we can create and use the cipher...
        const cipher = createCipheriv(algorithm, key, iv);

        let encrypted = '';
        cipher.setEncoding('hex');

        cipher.on('data', (chunk) => encrypted += chunk);
        cipher.on('end', () => console.log(encrypted));

        cipher.write('some clear text data');
        cipher.end();
      });
    });

Example: Using `Cipher` and piped streams:

    import {
      createReadStream,
      createWriteStream,
    } from 'fs';

    import {
      pipeline
    } from 'stream';

    const {
      scrypt,
      randomFill,
      createCipheriv
    } = await import('node:crypto');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';

    // First, we'll generate the key. The key length is dependent on the algorithm.
    // In this case for aes192, it is 24 bytes (192 bits).
    scrypt(password, 'salt', 24, (err, key) => {
      if (err) throw err;
      // Then, we'll generate a random initialization vector
      randomFill(new Uint8Array(16), (err, iv) => {
        if (err) throw err;

        const cipher = createCipheriv(algorithm, key, iv);

        const input = createReadStream('test.js');
        const output = createWriteStream('test.enc');

        pipeline(input, cipher, output, (err) => {
          if (err) throw err;
        });
      });
    });const {
      createReadStream,
      createWriteStream,
    } = require('node:fs');

    const {
      pipeline
    } = require('node:stream');

    const {
      scrypt,
      randomFill,
      createCipheriv,
    } = require('node:crypto');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';

    // First, we'll generate the key. The key length is dependent on the algorithm.
    // In this case for aes192, it is 24 bytes (192 bits).
    scrypt(password, 'salt', 24, (err, key) => {
      if (err) throw err;
      // Then, we'll generate a random initialization vector
      randomFill(new Uint8Array(16), (err, iv) => {
        if (err) throw err;

        const cipher = createCipheriv(algorithm, key, iv);

        const input = createReadStream('test.js');
        const output = createWriteStream('test.enc');

        pipeline(input, cipher, output, (err) => {
          if (err) throw err;
        });
      });
    });

Example: Using the `cipher.update()` and `cipher.final()` methods:

    const {
      scrypt,
      randomFill,
      createCipheriv
    } = await import('node:crypto');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';

    // First, we'll generate the key. The key length is dependent on the algorithm.
    // In this case for aes192, it is 24 bytes (192 bits).
    scrypt(password, 'salt', 24, (err, key) => {
      if (err) throw err;
      // Then, we'll generate a random initialization vector
      randomFill(new Uint8Array(16), (err, iv) => {
        if (err) throw err;

        const cipher = createCipheriv(algorithm, key, iv);

        let encrypted = cipher.update('some clear text data', 'utf8', 'hex');
        encrypted += cipher.final('hex');
        console.log(encrypted);
      });
    });const {
      scrypt,
      randomFill,
      createCipheriv,
    } = require('node:crypto');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';

    // First, we'll generate the key. The key length is dependent on the algorithm.
    // In this case for aes192, it is 24 bytes (192 bits).
    scrypt(password, 'salt', 24, (err, key) => {
      if (err) throw err;
      // Then, we'll generate a random initialization vector
      randomFill(new Uint8Array(16), (err, iv) => {
        if (err) throw err;

        const cipher = createCipheriv(algorithm, key, iv);

        let encrypted = cipher.update('some clear text data', 'utf8', 'hex');
        encrypted += cipher.final('hex');
        console.log(encrypted);
      });
    });

#### `cipher.final([outputEncoding])`#

Added in: v0.1.94

- `outputEncoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string> Any remaining enciphered contents. If `outputEncoding` is specified, a string is returned. If an `outputEncoding` is not provided, a `Buffer` is returned.

Once the `cipher.final()` method has been called, the `Cipher` object can no longer be used to encrypt data. Attempts to call `cipher.final()` more than once will result in an error being thrown.

#### `cipher.getAuthTag()`#

Added in: v1.0.0

- Returns: <Buffer> When using an authenticated encryption mode (`GCM`, `CCM`, `OCB`, and `chacha20-poly1305` are currently supported), the `cipher.getAuthTag()` method returns a `Buffer` containing the authentication tag that has been computed from the given data.

The `cipher.getAuthTag()` method should only be called after encryption has been completed using the `cipher.final()` method.

If the `authTagLength` option was set during the `cipher` instance's creation, this function will return exactly `authTagLength` bytes.

#### `cipher.setAAD(buffer[, options])`#

Added in: v1.0.0

- `buffer` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `options` <Object> `stream.transform` options
  - `plaintextLength` <number>
  - `encoding` <string> The string encoding to use when `buffer` is a string.
- Returns: <Cipher> for method chaining.

When using an authenticated encryption mode (`GCM`, `CCM`, `OCB`, and `chacha20-poly1305` are currently supported), the `cipher.setAAD()` method sets the value used for the additional authenticated data (AAD) input parameter.

The `plaintextLength` option is optional for `GCM` and `OCB`. When using `CCM`, the `plaintextLength` option must be specified and its value must match the length of the plaintext in bytes. See CCM mode.

The `cipher.setAAD()` method must be called before `cipher.update()`.

#### `cipher.setAutoPadding([autoPadding])`#

Added in: v0.7.1

- `autoPadding` <boolean> Default: `true`
- Returns: <Cipher> for method chaining.

When using block encryption algorithms, the `Cipher` class will automatically add padding to the input data to the appropriate block size. To disable the default padding call `cipher.setAutoPadding(false)`.

When `autoPadding` is `false`, the length of the entire input data must be a multiple of the cipher's block size or `cipher.final()` will throw an error. Disabling automatic padding is useful for non-standard padding, for instance using `0x0` instead of PKCS padding.

The `cipher.setAutoPadding()` method must be called before `cipher.final()`.

#### `cipher.update(data[, inputEncoding][, outputEncoding])`#

History

Version | Changes
--- | ---
v6.0.0 | The default `inputEncoding` changed from `binary` to `utf8`.
v0.1.94 | Added in: v0.1.94

- `data` <string> | <Buffer> | <TypedArray> | <DataView>
- `inputEncoding` <string> The encoding of the data.
- `outputEncoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Updates the cipher with `data`. If the `inputEncoding` argument is given, the `data` argument is a string using the specified encoding. If the `inputEncoding` argument is not given, `data` must be a `Buffer`, `TypedArray`, or `DataView`. If `data` is a `Buffer`, `TypedArray`, or `DataView`, then `inputEncoding` is ignored.

The `outputEncoding` specifies the output format of the enciphered data. If the `outputEncoding` is specified, a string using the specified encoding is returned. If no `outputEncoding` is provided, a `Buffer` is returned.

The `cipher.update()` method can be called multiple times with new data until `cipher.final()` is called. Calling `cipher.update()` after `cipher.final()` will result in an error being thrown.

### Class: `Decipher`#

Added in: v0.1.94

- Extends: <stream.Transform>

Instances of the `Decipher` class are used to decrypt data. The class can be used in one of two ways:

- As a stream that is both readable and writable, where plain encrypted data is written to produce unencrypted data on the readable side, or
- Using the `decipher.update()` and `decipher.final()` methods to produce the unencrypted data.

The `crypto.createDecipher()` or `crypto.createDecipheriv()` methods are used to create `Decipher` instances. `Decipher` objects are not to be created directly using the `new` keyword.

Example: Using `Decipher` objects as streams:

    import { Buffer } from 'node:buffer';
    const {
      scryptSync,
      createDecipheriv
    } = await import('node:crypto');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';
    // Key length is dependent on the algorithm. In this case for aes192, it is
    // 24 bytes (192 bits).
    // Use the async `crypto.scrypt()` instead.
    const key = scryptSync(password, 'salt', 24);
    // The IV is usually passed along with the ciphertext.
    const iv = Buffer.alloc(16, 0); // Initialization vector.

    const decipher = createDecipheriv(algorithm, key, iv);

    let decrypted = '';
    decipher.on('readable', () => {
      while (null !== (chunk = decipher.read())) {
        decrypted += chunk.toString('utf8');
      }
    });
    decipher.on('end', () => {
      console.log(decrypted);
      // Prints: some clear text data
    });

    // Encrypted with same algorithm, key and iv.
    const encrypted =
      'e5f79c5915c02171eec6b212d5520d44480993d7d622a7c4c2da32f6efda0ffa';
    decipher.write(encrypted, 'hex');
    decipher.end();const {
      scryptSync,
      createDecipheriv,
    } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';
    // Key length is dependent on the algorithm. In this case for aes192, it is
    // 24 bytes (192 bits).
    // Use the async `crypto.scrypt()` instead.
    const key = scryptSync(password, 'salt', 24);
    // The IV is usually passed along with the ciphertext.
    const iv = Buffer.alloc(16, 0); // Initialization vector.

    const decipher = createDecipheriv(algorithm, key, iv);

    let decrypted = '';
    decipher.on('readable', () => {
      while (null !== (chunk = decipher.read())) {
        decrypted += chunk.toString('utf8');
      }
    });
    decipher.on('end', () => {
      console.log(decrypted);
      // Prints: some clear text data
    });

    // Encrypted with same algorithm, key and iv.
    const encrypted =
      'e5f79c5915c02171eec6b212d5520d44480993d7d622a7c4c2da32f6efda0ffa';
    decipher.write(encrypted, 'hex');
    decipher.end();

Example: Using `Decipher` and piped streams:

    import {
      createReadStream,
      createWriteStream,
    } from 'fs';
    import { Buffer } from 'node:buffer';
    const {
      scryptSync,
      createDecipheriv
    } = await import('node:crypto');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';
    // Use the async `crypto.scrypt()` instead.
    const key = scryptSync(password, 'salt', 24);
    // The IV is usually passed along with the ciphertext.
    const iv = Buffer.alloc(16, 0); // Initialization vector.

    const decipher = createDecipheriv(algorithm, key, iv);

    const input = createReadStream('test.enc');
    const output = createWriteStream('test.js');

    input.pipe(decipher).pipe(output);const {
      createReadStream,
      createWriteStream,
    } = require('node:fs');
    const {
      scryptSync,
      createDecipheriv,
    } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';
    // Use the async `crypto.scrypt()` instead.
    const key = scryptSync(password, 'salt', 24);
    // The IV is usually passed along with the ciphertext.
    const iv = Buffer.alloc(16, 0); // Initialization vector.

    const decipher = createDecipheriv(algorithm, key, iv);

    const input = createReadStream('test.enc');
    const output = createWriteStream('test.js');

    input.pipe(decipher).pipe(output);

Example: Using the `decipher.update()` and `decipher.final()` methods:

    import { Buffer } from 'node:buffer';
    const {
      scryptSync,
      createDecipheriv
    } = await import('node:crypto');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';
    // Use the async `crypto.scrypt()` instead.
    const key = scryptSync(password, 'salt', 24);
    // The IV is usually passed along with the ciphertext.
    const iv = Buffer.alloc(16, 0); // Initialization vector.

    const decipher = createDecipheriv(algorithm, key, iv);

    // Encrypted using same algorithm, key and iv.
    const encrypted =
      'e5f79c5915c02171eec6b212d5520d44480993d7d622a7c4c2da32f6efda0ffa';
    let decrypted = decipher.update(encrypted, 'hex', 'utf8');
    decrypted += decipher.final('utf8');
    console.log(decrypted);
    // Prints: some clear text dataconst {
      scryptSync,
      createDecipheriv,
    } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    const algorithm = 'aes-192-cbc';
    const password = 'Password used to generate key';
    // Use the async `crypto.scrypt()` instead.
    const key = scryptSync(password, 'salt', 24);
    // The IV is usually passed along with the ciphertext.
    const iv = Buffer.alloc(16, 0); // Initialization vector.

    const decipher = createDecipheriv(algorithm, key, iv);

    // Encrypted using same algorithm, key and iv.
    const encrypted =
      'e5f79c5915c02171eec6b212d5520d44480993d7d622a7c4c2da32f6efda0ffa';
    let decrypted = decipher.update(encrypted, 'hex', 'utf8');
    decrypted += decipher.final('utf8');
    console.log(decrypted);
    // Prints: some clear text data

#### `decipher.final([outputEncoding])`#

Added in: v0.1.94

- `outputEncoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string> Any remaining deciphered contents. If `outputEncoding` is specified, a string is returned. If an `outputEncoding` is not provided, a `Buffer` is returned.

Once the `decipher.final()` method has been called, the `Decipher` object can no longer be used to decrypt data. Attempts to call `decipher.final()` more than once will result in an error being thrown.

#### `decipher.setAAD(buffer[, options])`#

History

Version | Changes
--- | ---
v15.0.0 | The buffer argument can be a string or ArrayBuffer and is limited to no more than 2 ** 31 - 1 bytes.
v7.2.0 | This method now returns a reference to `decipher`.
v1.0.0 | Added in: v1.0.0

- `buffer` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `options` <Object> `stream.transform` options
  - `plaintextLength` <number>
  - `encoding` <string> String encoding to use when `buffer` is a string.
- Returns: <Decipher> for method chaining.

When using an authenticated encryption mode (`GCM`, `CCM`, `OCB`, and `chacha20-poly1305` are currently supported), the `decipher.setAAD()` method sets the value used for the additional authenticated data (AAD) input parameter.

The `options` argument is optional for `GCM`. When using `CCM`, the `plaintextLength` option must be specified and its value must match the length of the ciphertext in bytes. See CCM mode.

The `decipher.setAAD()` method must be called before `decipher.update()`.

When passing a string as the `buffer`, please consider caveats when using strings as inputs to cryptographic APIs.

#### `decipher.setAuthTag(buffer[, encoding])`#

History

Version | Changes
--- | ---
v15.0.0 | The buffer argument can be a string or ArrayBuffer and is limited to no more than 2 ** 31 - 1 bytes.
v11.0.0 | This method now throws if the GCM tag length is invalid.
v7.2.0 | This method now returns a reference to `decipher`.
v1.0.0 | Added in: v1.0.0

- `buffer` <string> | <Buffer> | <ArrayBuffer> | <TypedArray> | <DataView>
- `encoding` <string> String encoding to use when `buffer` is a string.
- Returns: <Decipher> for method chaining.

When using an authenticated encryption mode (`GCM`, `CCM`, `OCB`, and `chacha20-poly1305` are currently supported), the `decipher.setAuthTag()` method is used to pass in the received authentication tag. If no tag is provided, or if the cipher text has been tampered with, `decipher.final()` will throw, indicating that the cipher text should be discarded due to failed authentication. If the tag length is invalid according to NIST SP 800-38D or does not match the value of the `authTagLength` option, `decipher.setAuthTag()` will throw an error.

The `decipher.setAuthTag()` method must be called before `decipher.update()` for `CCM` mode or before `decipher.final()` for `GCM` and `OCB` modes and `chacha20-poly1305`. `decipher.setAuthTag()` can only be called once.

When passing a string as the authentication tag, please consider caveats when using strings as inputs to cryptographic APIs.

#### `decipher.setAutoPadding([autoPadding])`#

Added in: v0.7.1

- `autoPadding` <boolean> Default: `true`
- Returns: <Decipher> for method chaining.

When data has been encrypted without standard block padding, calling `decipher.setAutoPadding(false)` will disable automatic padding to prevent `decipher.final()` from checking for and removing padding.

Turning auto padding off will only work if the input data's length is a multiple of the ciphers block size.

The `decipher.setAutoPadding()` method must be called before `decipher.final()`.

#### `decipher.update(data[, inputEncoding][, outputEncoding])`#

History

Version | Changes
--- | ---
v6.0.0 | The default `inputEncoding` changed from `binary` to `utf8`.
v0.1.94 | Added in: v0.1.94

- `data` <string> | <Buffer> | <TypedArray> | <DataView>
- `inputEncoding` <string> The encoding of the `data` string.
- `outputEncoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Updates the decipher with `data`. If the `inputEncoding` argument is given, the `data` argument is a string using the specified encoding. If the `inputEncoding` argument is not given, `data` must be a `Buffer`. If `data` is a `Buffer` then `inputEncoding` is ignored.

The `outputEncoding` specifies the output format of the enciphered data. If the `outputEncoding` is specified, a string using the specified encoding is returned. If no `outputEncoding` is provided, a `Buffer` is returned.

The `decipher.update()` method can be called multiple times with new data until `decipher.final()` is called. Calling `decipher.update()` after `decipher.final()` will result in an error being thrown.

### Class: `DiffieHellman`#

Added in: v0.5.0

The `DiffieHellman` class is a utility for creating Diffie-Hellman key exchanges.

Instances of the `DiffieHellman` class can be created using the `crypto.createDiffieHellman()` function.

    import assert from 'node:assert';

    const {
      createDiffieHellman
    } = await import('node:crypto');

    // Generate Alice's keys...
    const alice = createDiffieHellman(2048);
    const aliceKey = alice.generateKeys();

    // Generate Bob's keys...
    const bob = createDiffieHellman(alice.getPrime(), alice.getGenerator());
    const bobKey = bob.generateKeys();

    // Exchange and generate the secret...
    const aliceSecret = alice.computeSecret(bobKey);
    const bobSecret = bob.computeSecret(aliceKey);

    // OK
    assert.strictEqual(aliceSecret.toString('hex'), bobSecret.toString('hex'));const assert = require('node:assert');

    const {
      createDiffieHellman,
    } = require('node:crypto');

    // Generate Alice's keys...
    const alice = createDiffieHellman(2048);
    const aliceKey = alice.generateKeys();

    // Generate Bob's keys...
    const bob = createDiffieHellman(alice.getPrime(), alice.getGenerator());
    const bobKey = bob.generateKeys();

    // Exchange and generate the secret...
    const aliceSecret = alice.computeSecret(bobKey);
    const bobSecret = bob.computeSecret(aliceKey);

    // OK
    assert.strictEqual(aliceSecret.toString('hex'), bobSecret.toString('hex'));

#### `diffieHellman.computeSecret(otherPublicKey[, inputEncoding][, outputEncoding])`#

Added in: v0.5.0

- `otherPublicKey` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `inputEncoding` <string> The encoding of an `otherPublicKey` string.
- `outputEncoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Computes the shared secret using `otherPublicKey` as the other party's public key and returns the computed shared secret. The supplied key is interpreted using the specified `inputEncoding`, and secret is encoded using specified `outputEncoding`. If the `inputEncoding` is not provided, `otherPublicKey` is expected to be a `Buffer`, `TypedArray`, or `DataView`.

If `outputEncoding` is given a string is returned; otherwise, a `Buffer` is returned.

#### `diffieHellman.generateKeys([encoding])`#

Added in: v0.5.0

- `encoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Generates private and public Diffie-Hellman key values, and returns the public key in the specified `encoding`. This key should be transferred to the other party. If `encoding` is provided a string is returned; otherwise a `Buffer` is returned.

#### `diffieHellman.getGenerator([encoding])`#

Added in: v0.5.0

- `encoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Returns the Diffie-Hellman generator in the specified `encoding`. If `encoding` is provided a string is returned; otherwise a `Buffer` is returned.

#### `diffieHellman.getPrime([encoding])`#

Added in: v0.5.0

- `encoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Returns the Diffie-Hellman prime in the specified `encoding`. If `encoding` is provided a string is returned; otherwise a `Buffer` is returned.

#### `diffieHellman.getPrivateKey([encoding])`#

Added in: v0.5.0

- `encoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Returns the Diffie-Hellman private key in the specified `encoding`. If `encoding` is provided a string is returned; otherwise a `Buffer` is returned.

#### `diffieHellman.getPublicKey([encoding])`#

Added in: v0.5.0

- `encoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Returns the Diffie-Hellman public key in the specified `encoding`. If `encoding` is provided a string is returned; otherwise a `Buffer` is returned.

#### `diffieHellman.setPrivateKey(privateKey[, encoding])`#

Added in: v0.5.0

- `privateKey` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The encoding of the `privateKey` string.

Sets the Diffie-Hellman private key. If the `encoding` argument is provided, `privateKey` is expected to be a string. If no `encoding` is provided, `privateKey` is expected to be a `Buffer`, `TypedArray`, or `DataView`.

#### `diffieHellman.setPublicKey(publicKey[, encoding])`#

Added in: v0.5.0

- `publicKey` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The encoding of the `publicKey` string.

Sets the Diffie-Hellman public key. If the `encoding` argument is provided, `publicKey` is expected to be a string. If no `encoding` is provided, `publicKey` is expected to be a `Buffer`, `TypedArray`, or `DataView`.

#### `diffieHellman.verifyError`#

Added in: v0.11.12

A bit field containing any warnings and/or errors resulting from a check performed during initialization of the `DiffieHellman` object.

The following values are valid for this property (as defined in `node:constants` module):

- `DH_CHECK_P_NOT_SAFE_PRIME`
- `DH_CHECK_P_NOT_PRIME`
- `DH_UNABLE_TO_CHECK_GENERATOR`
- `DH_NOT_SUITABLE_GENERATOR`

### Class: `DiffieHellmanGroup`#

Added in: v0.7.5

The `DiffieHellmanGroup` class takes a well-known modp group as its argument. It works the same as `DiffieHellman`, except that it does not allow changing its keys after creation. In other words, it does not implement `setPublicKey()` or `setPrivateKey()` methods.

    const { createDiffieHellmanGroup } = await import('node:crypto');
    const dh = createDiffieHellmanGroup('modp1');const { createDiffieHellmanGroup } = require('node:crypto');
    const dh = createDiffieHellmanGroup('modp1');

The name (e.g. `'modp1'`) is taken from RFC 2412 (modp1 and 2) and RFC 3526:

    $ perl -ne 'print "$1\n" if /"(modp\d+)"/' src/node_crypto_groups.h
    modp1  #  768 bits
    modp2  # 1024 bits
    modp5  # 1536 bits
    modp14 # 2048 bits
    modp15 # etc.
    modp16
    modp17
    modp18

### Class: `ECDH`#

Added in: v0.11.14

The `ECDH` class is a utility for creating Elliptic Curve Diffie-Hellman (ECDH) key exchanges.

Instances of the `ECDH` class can be created using the `crypto.createECDH()` function.

    import assert from 'node:assert';

    const {
      createECDH
    } = await import('node:crypto');

    // Generate Alice's keys...
    const alice = createECDH('secp521r1');
    const aliceKey = alice.generateKeys();

    // Generate Bob's keys...
    const bob = createECDH('secp521r1');
    const bobKey = bob.generateKeys();

    // Exchange and generate the secret...
    const aliceSecret = alice.computeSecret(bobKey);
    const bobSecret = bob.computeSecret(aliceKey);

    assert.strictEqual(aliceSecret.toString('hex'), bobSecret.toString('hex'));
    // OKconst assert = require('node:assert');

    const {
      createECDH,
    } = require('node:crypto');

    // Generate Alice's keys...
    const alice = createECDH('secp521r1');
    const aliceKey = alice.generateKeys();

    // Generate Bob's keys...
    const bob = createECDH('secp521r1');
    const bobKey = bob.generateKeys();

    // Exchange and generate the secret...
    const aliceSecret = alice.computeSecret(bobKey);
    const bobSecret = bob.computeSecret(aliceKey);

    assert.strictEqual(aliceSecret.toString('hex'), bobSecret.toString('hex'));
    // OK

#### Static method: `ECDH.convertKey(key, curve[, inputEncoding[, outputEncoding[, format]]])`#

Added in: v10.0.0

- `key` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `curve` <string>
- `inputEncoding` <string> The encoding of the `key` string.
- `outputEncoding` <string> The encoding of the return value.
- `format` <string> Default: `'uncompressed'`
- Returns: <Buffer> | <string>

Converts the EC Diffie-Hellman public key specified by `key` and `curve` to the format specified by `format`. The `format` argument specifies point encoding and can be `'compressed'`, `'uncompressed'` or `'hybrid'`. The supplied key is interpreted using the specified `inputEncoding`, and the returned key is encoded using the specified `outputEncoding`.

Use `crypto.getCurves()` to obtain a list of available curve names. On recent OpenSSL releases, `openssl ecparam -list_curves` will also display the name and description of each available elliptic curve.

If `format` is not specified the point will be returned in `'uncompressed'` format.

If the `inputEncoding` is not provided, `key` is expected to be a `Buffer`, `TypedArray`, or `DataView`.

Example (uncompressing a key):

    const {
      createECDH,
      ECDH
    } = await import('node:crypto');

    const ecdh = createECDH('secp256k1');
    ecdh.generateKeys();

    const compressedKey = ecdh.getPublicKey('hex', 'compressed');

    const uncompressedKey = ECDH.convertKey(compressedKey,
                                            'secp256k1',
                                            'hex',
                                            'hex',
                                            'uncompressed');

    // The converted key and the uncompressed public key should be the same
    console.log(uncompressedKey === ecdh.getPublicKey('hex'));const {
      createECDH,
      ECDH,
    } = require('node:crypto');

    const ecdh = createECDH('secp256k1');
    ecdh.generateKeys();

    const compressedKey = ecdh.getPublicKey('hex', 'compressed');

    const uncompressedKey = ECDH.convertKey(compressedKey,
                                            'secp256k1',
                                            'hex',
                                            'hex',
                                            'uncompressed');

    // The converted key and the uncompressed public key should be the same
    console.log(uncompressedKey === ecdh.getPublicKey('hex'));

#### `ecdh.computeSecret(otherPublicKey[, inputEncoding][, outputEncoding])`#

History

Version | Changes
--- | ---
v10.0.0 | Changed error format to better support invalid public key error.
v6.0.0 | The default `inputEncoding` changed from `binary` to `utf8`.
v0.11.14 | Added in: v0.11.14

- `otherPublicKey` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `inputEncoding` <string> The encoding of the `otherPublicKey` string.
- `outputEncoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Computes the shared secret using `otherPublicKey` as the other party's public key and returns the computed shared secret. The supplied key is interpreted using specified `inputEncoding`, and the returned secret is encoded using the specified `outputEncoding`. If the `inputEncoding` is not provided, `otherPublicKey` is expected to be a `Buffer`, `TypedArray`, or `DataView`.

If `outputEncoding` is given a string will be returned; otherwise a `Buffer` is returned.

`ecdh.computeSecret` will throw an `ERR_CRYPTO_ECDH_INVALID_PUBLIC_KEY` error when `otherPublicKey` lies outside of the elliptic curve. Since `otherPublicKey` is usually supplied from a remote user over an insecure network, be sure to handle this exception accordingly.

#### `ecdh.generateKeys([encoding[, format]])`#

Added in: v0.11.14

- `encoding` <string> The encoding of the return value.
- `format` <string> Default: `'uncompressed'`
- Returns: <Buffer> | <string>

Generates private and public EC Diffie-Hellman key values, and returns the public key in the specified `format` and `encoding`. This key should be transferred to the other party.

The `format` argument specifies point encoding and can be `'compressed'` or `'uncompressed'`. If `format` is not specified, the point will be returned in `'uncompressed'` format.

If `encoding` is provided a string is returned; otherwise a `Buffer` is returned.

#### `ecdh.getPrivateKey([encoding])`#

Added in: v0.11.14

- `encoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string> The EC Diffie-Hellman in the specified `encoding`.

If `encoding` is specified, a string is returned; otherwise a `Buffer` is returned.

#### `ecdh.getPublicKey([encoding][, format])`#

Added in: v0.11.14

- `encoding` <string> The encoding of the return value.
- `format` <string> Default: `'uncompressed'`
- Returns: <Buffer> | <string> The EC Diffie-Hellman public key in the specified `encoding` and `format`.

The `format` argument specifies point encoding and can be `'compressed'` or `'uncompressed'`. If `format` is not specified the point will be returned in `'uncompressed'` format.

If `encoding` is specified, a string is returned; otherwise a `Buffer` is returned.

#### `ecdh.setPrivateKey(privateKey[, encoding])`#

Added in: v0.11.14

- `privateKey` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The encoding of the `privateKey` string.

Sets the EC Diffie-Hellman private key. If `encoding` is provided, `privateKey` is expected to be a string; otherwise `privateKey` is expected to be a `Buffer`, `TypedArray`, or `DataView`.

If `privateKey` is not valid for the curve specified when the `ECDH` object was created, an error is thrown. Upon setting the private key, the associated public point (key) is also generated and set in the `ECDH` object.

#### `ecdh.setPublicKey(publicKey[, encoding])`#

Added in: v0.11.14 Deprecated since: v5.2.0

Stability: 0 - Deprecated

- `publicKey` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The encoding of the `publicKey` string.

Sets the EC Diffie-Hellman public key. If `encoding` is provided `publicKey` is expected to be a string; otherwise a `Buffer`, `TypedArray`, or `DataView` is expected.

There is not normally a reason to call this method because `ECDH` only requires a private key and the other party's public key to compute the shared secret. Typically either `ecdh.generateKeys()` or `ecdh.setPrivateKey()` will be called. The `ecdh.setPrivateKey()` method attempts to generate the public point/key associated with the private key being set.

Example (obtaining a shared secret):

    const {
      createECDH,
      createHash
    } = await import('node:crypto');

    const alice = createECDH('secp256k1');
    const bob = createECDH('secp256k1');

    // This is a shortcut way of specifying one of Alice's previous private
    // keys. It would be unwise to use such a predictable private key in a real
    // application.
    alice.setPrivateKey(
      createHash('sha256').update('alice', 'utf8').digest()
    );

    // Bob uses a newly generated cryptographically strong
    // pseudorandom key pair
    bob.generateKeys();

    const aliceSecret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
    const bobSecret = bob.computeSecret(alice.getPublicKey(), null, 'hex');

    // aliceSecret and bobSecret should be the same shared secret value
    console.log(aliceSecret === bobSecret);const {
      createECDH,
      createHash,
    } = require('node:crypto');

    const alice = createECDH('secp256k1');
    const bob = createECDH('secp256k1');

    // This is a shortcut way of specifying one of Alice's previous private
    // keys. It would be unwise to use such a predictable private key in a real
    // application.
    alice.setPrivateKey(
      createHash('sha256').update('alice', 'utf8').digest()
    );

    // Bob uses a newly generated cryptographically strong
    // pseudorandom key pair
    bob.generateKeys();

    const aliceSecret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
    const bobSecret = bob.computeSecret(alice.getPublicKey(), null, 'hex');

    // aliceSecret and bobSecret should be the same shared secret value
    console.log(aliceSecret === bobSecret);

### Class: `Hash`#

Added in: v0.1.92

- Extends: <stream.Transform>

The `Hash` class is a utility for creating hash digests of data. It can be used in one of two ways:

- As a stream that is both readable and writable, where data is written to produce a computed hash digest on the readable side, or
- Using the `hash.update()` and `hash.digest()` methods to produce the computed hash.

The `crypto.createHash()` method is used to create `Hash` instances. `Hash` objects are not to be created directly using the `new` keyword.

Example: Using `Hash` objects as streams:

    const {
      createHash
    } = await import('node:crypto');

    const hash = createHash('sha256');

    hash.on('readable', () => {
      // Only one element is going to be produced by the
      // hash stream.
      const data = hash.read();
      if (data) {
        console.log(data.toString('hex'));
        // Prints:
        //   6a2da20943931e9834fc12cfe5bb47bbd9ae43489a30726962b576f4e3993e50
      }
    });

    hash.write('some data to hash');
    hash.end();const {
      createHash,
    } = require('node:crypto');

    const hash = createHash('sha256');

    hash.on('readable', () => {
      // Only one element is going to be produced by the
      // hash stream.
      const data = hash.read();
      if (data) {
        console.log(data.toString('hex'));
        // Prints:
        //   6a2da20943931e9834fc12cfe5bb47bbd9ae43489a30726962b576f4e3993e50
      }
    });

    hash.write('some data to hash');
    hash.end();

Example: Using `Hash` and piped streams:

    import { createReadStream } from 'node:fs';
    import { stdout } from 'node:process';
    const { createHash } = await import('node:crypto');

    const hash = createHash('sha256');

    const input = createReadStream('test.js');
    input.pipe(hash).setEncoding('hex').pipe(stdout);const { createReadStream } = require('node:fs');
    const { createHash } = require('node:crypto');
    const { stdout } = require('node:process');

    const hash = createHash('sha256');

    const input = createReadStream('test.js');
    input.pipe(hash).setEncoding('hex').pipe(stdout);

Example: Using the `hash.update()` and `hash.digest()` methods:

    const {
      createHash
    } = await import('node:crypto');

    const hash = createHash('sha256');

    hash.update('some data to hash');
    console.log(hash.digest('hex'));
    // Prints:
    //   6a2da20943931e9834fc12cfe5bb47bbd9ae43489a30726962b576f4e3993e50const {
      createHash,
    } = require('node:crypto');

    const hash = createHash('sha256');

    hash.update('some data to hash');
    console.log(hash.digest('hex'));
    // Prints:
    //   6a2da20943931e9834fc12cfe5bb47bbd9ae43489a30726962b576f4e3993e50

#### `hash.copy([options])`#

Added in: v13.1.0

- `options` <Object> `stream.transform` options
- Returns: <Hash>

Creates a new `Hash` object that contains a deep copy of the internal state of the current `Hash` object.

The optional `options` argument controls stream behavior. For XOF hash functions such as `'shake256'`, the `outputLength` option can be used to specify the desired output length in bytes.

An error is thrown when an attempt is made to copy the `Hash` object after its `hash.digest()` method has been called.

    // Calculate a rolling hash.
    const {
      createHash
    } = await import('node:crypto');

    const hash = createHash('sha256');

    hash.update('one');
    console.log(hash.copy().digest('hex'));

    hash.update('two');
    console.log(hash.copy().digest('hex'));

    hash.update('three');
    console.log(hash.copy().digest('hex'));

    // Etc.// Calculate a rolling hash.
    const {
      createHash,
    } = require('node:crypto');

    const hash = createHash('sha256');

    hash.update('one');
    console.log(hash.copy().digest('hex'));

    hash.update('two');
    console.log(hash.copy().digest('hex'));

    hash.update('three');
    console.log(hash.copy().digest('hex'));

    // Etc.

#### `hash.digest([encoding])`#

Added in: v0.1.92

- `encoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Calculates the digest of all of the data passed to be hashed (using the `hash.update()` method). If `encoding` is provided a string will be returned; otherwise a `Buffer` is returned.

The `Hash` object can not be used again after `hash.digest()` method has been called. Multiple calls will cause an error to be thrown.

#### `hash.update(data[, inputEncoding])`#

History

Version | Changes
--- | ---
v6.0.0 | The default `inputEncoding` changed from `binary` to `utf8`.
v0.1.92 | Added in: v0.1.92

- `data` <string> | <Buffer> | <TypedArray> | <DataView>
- `inputEncoding` <string> The encoding of the `data` string.

Updates the hash content with the given `data`, the encoding of which is given in `inputEncoding`. If `encoding` is not provided, and the `data` is a string, an encoding of `'utf8'` is enforced. If `data` is a `Buffer`, `TypedArray`, or `DataView`, then `inputEncoding` is ignored.

This can be called many times with new data as it is streamed.

### Class: `Hmac`#

Added in: v0.1.94

- Extends: <stream.Transform>

The `Hmac` class is a utility for creating cryptographic HMAC digests. It can be used in one of two ways:

- As a stream that is both readable and writable, where data is written to produce a computed HMAC digest on the readable side, or
- Using the `hmac.update()` and `hmac.digest()` methods to produce the computed HMAC digest.

The `crypto.createHmac()` method is used to create `Hmac` instances. `Hmac` objects are not to be created directly using the `new` keyword.

Example: Using `Hmac` objects as streams:

    const {
      createHmac
    } = await import('node:crypto');

    const hmac = createHmac('sha256', 'a secret');

    hmac.on('readable', () => {
      // Only one element is going to be produced by the
      // hash stream.
      const data = hmac.read();
      if (data) {
        console.log(data.toString('hex'));
        // Prints:
        //   7fd04df92f636fd450bc841c9418e5825c17f33ad9c87c518115a45971f7f77e
      }
    });

    hmac.write('some data to hash');
    hmac.end();const {
      createHmac,
    } = require('node:crypto');

    const hmac = createHmac('sha256', 'a secret');

    hmac.on('readable', () => {
      // Only one element is going to be produced by the
      // hash stream.
      const data = hmac.read();
      if (data) {
        console.log(data.toString('hex'));
        // Prints:
        //   7fd04df92f636fd450bc841c9418e5825c17f33ad9c87c518115a45971f7f77e
      }
    });

    hmac.write('some data to hash');
    hmac.end();

Example: Using `Hmac` and piped streams:

    import { createReadStream } from 'node:fs';
    import { stdout } from 'node:process';
    const {
      createHmac
    } = await import('node:crypto');

    const hmac = createHmac('sha256', 'a secret');

    const input = createReadStream('test.js');
    input.pipe(hmac).pipe(stdout);const {
      createReadStream,
    } = require('node:fs');
    const {
      createHmac,
    } = require('node:crypto');
    const { stdout } = require('node:process');

    const hmac = createHmac('sha256', 'a secret');

    const input = createReadStream('test.js');
    input.pipe(hmac).pipe(stdout);

Example: Using the `hmac.update()` and `hmac.digest()` methods:

    const {
      createHmac
    } = await import('node:crypto');

    const hmac = createHmac('sha256', 'a secret');

    hmac.update('some data to hash');
    console.log(hmac.digest('hex'));
    // Prints:
    //   7fd04df92f636fd450bc841c9418e5825c17f33ad9c87c518115a45971f7f77econst {
      createHmac,
    } = require('node:crypto');

    const hmac = createHmac('sha256', 'a secret');

    hmac.update('some data to hash');
    console.log(hmac.digest('hex'));
    // Prints:
    //   7fd04df92f636fd450bc841c9418e5825c17f33ad9c87c518115a45971f7f77e

#### `hmac.digest([encoding])`#

Added in: v0.1.94

- `encoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Calculates the HMAC digest of all of the data passed using `hmac.update()`. If `encoding` is provided a string is returned; otherwise a `Buffer` is returned;

The `Hmac` object can not be used again after `hmac.digest()` has been called. Multiple calls to `hmac.digest()` will result in an error being thrown.

#### `hmac.update(data[, inputEncoding])`#

History

Version | Changes
--- | ---
v6.0.0 | The default `inputEncoding` changed from `binary` to `utf8`.
v0.1.94 | Added in: v0.1.94

- `data` <string> | <Buffer> | <TypedArray> | <DataView>
- `inputEncoding` <string> The encoding of the `data` string.

Updates the `Hmac` content with the given `data`, the encoding of which is given in `inputEncoding`. If `encoding` is not provided, and the `data` is a string, an encoding of `'utf8'` is enforced. If `data` is a `Buffer`, `TypedArray`, or `DataView`, then `inputEncoding` is ignored.

This can be called many times with new data as it is streamed.

### Class: `KeyObject`#

History

Version | Changes
--- | ---
v14.5.0, v12.19.0 | Instances of this class can now be passed to worker threads using `postMessage`.
v11.13.0 | This class is now exported.
v11.6.0 | Added in: v11.6.0

Node.js uses a `KeyObject` class to represent a symmetric or asymmetric key, and each kind of key exposes different functions. The `crypto.createSecretKey()`, `crypto.createPublicKey()` and `crypto.createPrivateKey()` methods are used to create `KeyObject` instances. `KeyObject` objects are not to be created directly using the `new` keyword.

Most applications should consider using the new `KeyObject` API instead of passing keys as strings or `Buffer`s due to improved security features.

`KeyObject` instances can be passed to other threads via `postMessage()`. The receiver obtains a cloned `KeyObject`, and the `KeyObject` does not need to be listed in the `transferList` argument.

#### Static method: `KeyObject.from(key)`#

Added in: v15.0.0

- `key` <CryptoKey>
- Returns: <KeyObject>

Example: Converting a `CryptoKey` instance to a `KeyObject`:

    const { webcrypto, KeyObject } = await import('node:crypto');
    const { subtle } = webcrypto;

    const key = await subtle.generateKey({
      name: 'HMAC',
      hash: 'SHA-256',
      length: 256
    }, true, ['sign', 'verify']);

    const keyObject = KeyObject.from(key);
    console.log(keyObject.symmetricKeySize);
    // Prints: 32 (symmetric key size in bytes)const {
      webcrypto: {
        subtle,
      },
      KeyObject,
    } = require('node:crypto');

    (async function() {
      const key = await subtle.generateKey({
        name: 'HMAC',
        hash: 'SHA-256',
        length: 256
      }, true, ['sign', 'verify']);

      const keyObject = KeyObject.from(key);
      console.log(keyObject.symmetricKeySize);
      // Prints: 32 (symmetric key size in bytes)
    })();

#### `keyObject.asymmetricKeyDetails`#

History

Version | Changes
--- | ---
v16.9.0 | Expose `RSASSA-PSS-params` sequence parameters for RSA-PSS keys.
v15.7.0 | Added in: v15.7.0

- <Object>
  - `modulusLength`: <number> Key size in bits (RSA, DSA).
  - `publicExponent`: <bigint> Public exponent (RSA).
  - `hashAlgorithm`: <string> Name of the message digest (RSA-PSS).
  - `mgf1HashAlgorithm`: <string> Name of the message digest used by MGF1 (RSA-PSS).
  - `saltLength`: <number> Minimal salt length in bytes (RSA-PSS).
  - `divisorLength`: <number> Size of `q` in bits (DSA).
  - `namedCurve`: <string> Name of the curve (EC).

This property exists only on asymmetric keys. Depending on the type of the key, this object contains information about the key. None of the information obtained through this property can be used to uniquely identify a key or to compromise the security of the key.

For RSA-PSS keys, if the key material contains a `RSASSA-PSS-params` sequence, the `hashAlgorithm`, `mgf1HashAlgorithm`, and `saltLength` properties will be set.

Other key details might be exposed via this API using additional attributes.

#### `keyObject.asymmetricKeyType`#

History

Version | Changes
--- | ---
v13.9.0, v12.17.0 | Added support for `'dh'`.
v12.0.0 | Added support for `'rsa-pss'`.
v12.0.0 | This property now returns `undefined` for KeyObject instances of unrecognized type instead of aborting.
v12.0.0 | Added support for `'x25519'` and `'x448'`.
v12.0.0 | Added support for `'ed25519'` and `'ed448'`.
v11.6.0 | Added in: v11.6.0

- <string>

For asymmetric keys, this property represents the type of the key. Supported key types are:

- `'rsa'` (OID 1.2.840.113549.1.1.1)
- `'rsa-pss'` (OID 1.2.840.113549.1.1.10)
- `'dsa'` (OID 1.2.840.10040.4.1)
- `'ec'` (OID 1.2.840.10045.2.1)
- `'x25519'` (OID 1.3.101.110)
- `'x448'` (OID 1.3.101.111)
- `'ed25519'` (OID 1.3.101.112)
- `'ed448'` (OID 1.3.101.113)
- `'dh'` (OID 1.2.840.113549.1.3.1)

This property is `undefined` for unrecognized `KeyObject` types and symmetric keys.

#### `keyObject.export([options])`#

History

Version | Changes
--- | ---
v15.9.0 | Added support for `'jwk'` format.
v11.6.0 | Added in: v11.6.0

- `options`: <Object>
- Returns: <string> | <Buffer> | <Object>

For symmetric keys, the following encoding options can be used:

- `format`: <string> Must be `'buffer'` (default) or `'jwk'`.

For public keys, the following encoding options can be used:

- `type`: <string> Must be one of `'pkcs1'` (RSA only) or `'spki'`.
- `format`: <string> Must be `'pem'`, `'der'`, or `'jwk'`.

For private keys, the following encoding options can be used:

- `type`: <string> Must be one of `'pkcs1'` (RSA only), `'pkcs8'` or `'sec1'` (EC only).
- `format`: <string> Must be `'pem'`, `'der'`, or `'jwk'`.
- `cipher`: <string> If specified, the private key will be encrypted with the given `cipher` and `passphrase` using PKCS#5 v2.0 password based encryption.
- `passphrase`: <string> | <Buffer> The passphrase to use for encryption, see `cipher`.

The result type depends on the selected encoding format, when PEM the result is a string, when DER it will be a buffer containing the data encoded as DER, when JWK it will be an object.

When JWK encoding format was selected, all other encoding options are ignored.

PKCS#1, SEC1, and PKCS#8 type keys can be encrypted by using a combination of the `cipher` and `format` options. The PKCS#8 `type` can be used with any `format` to encrypt any key algorithm (RSA, EC, or DH) by specifying a `cipher`. PKCS#1 and SEC1 can only be encrypted by specifying a `cipher` when the PEM `format` is used. For maximum compatibility, use PKCS#8 for encrypted private keys. Since PKCS#8 defines its own encryption mechanism, PEM-level encryption is not supported when encrypting a PKCS#8 key. See RFC 5208 for PKCS#8 encryption and RFC 1421 for PKCS#1 and SEC1 encryption.

#### `keyObject.equals(otherKeyObject)`#

Added in: v17.7.0, v16.15.0

- `otherKeyObject`: <KeyObject> A `KeyObject` with which to compare `keyObject`.
- Returns: <boolean>

Returns `true` or `false` depending on whether the keys have exactly the same type, value, and parameters. This method is not constant time.

#### `keyObject.symmetricKeySize`#

Added in: v11.6.0

- <number>

For secret keys, this property represents the size of the key in bytes. This property is `undefined` for asymmetric keys.

#### `keyObject.type`#

Added in: v11.6.0

- <string>

Depending on the type of this `KeyObject`, this property is either `'secret'` for secret (symmetric) keys, `'public'` for public (asymmetric) keys or `'private'` for private (asymmetric) keys.

### Class: `Sign`#

Added in: v0.1.92

- Extends: <stream.Writable>

The `Sign` class is a utility for generating signatures. It can be used in one of two ways:

- As a writable stream, where data to be signed is written and the `sign.sign()` method is used to generate and return the signature, or
- Using the `sign.update()` and `sign.sign()` methods to produce the signature.

The `crypto.createSign()` method is used to create `Sign` instances. The argument is the string name of the hash function to use. `Sign` objects are not to be created directly using the `new` keyword.

Example: Using `Sign` and `Verify` objects as streams:

    const {
      generateKeyPairSync,
      createSign,
      createVerify
    } = await import('node:crypto');

    const { privateKey, publicKey } = generateKeyPairSync('ec', {
      namedCurve: 'sect239k1'
    });

    const sign = createSign('SHA256');
    sign.write('some data to sign');
    sign.end();
    const signature = sign.sign(privateKey, 'hex');

    const verify = createVerify('SHA256');
    verify.write('some data to sign');
    verify.end();
    console.log(verify.verify(publicKey, signature, 'hex'));
    // Prints: trueconst {
      generateKeyPairSync,
      createSign,
      createVerify,
    } = require('node:crypto');

    const { privateKey, publicKey } = generateKeyPairSync('ec', {
      namedCurve: 'sect239k1'
    });

    const sign = createSign('SHA256');
    sign.write('some data to sign');
    sign.end();
    const signature = sign.sign(privateKey, 'hex');

    const verify = createVerify('SHA256');
    verify.write('some data to sign');
    verify.end();
    console.log(verify.verify(publicKey, signature, 'hex'));
    // Prints: true

Example: Using the `sign.update()` and `verify.update()` methods:

    const {
      generateKeyPairSync,
      createSign,
      createVerify
    } = await import('node:crypto');

    const { privateKey, publicKey } = generateKeyPairSync('rsa', {
      modulusLength: 2048,
    });

    const sign = createSign('SHA256');
    sign.update('some data to sign');
    sign.end();
    const signature = sign.sign(privateKey);

    const verify = createVerify('SHA256');
    verify.update('some data to sign');
    verify.end();
    console.log(verify.verify(publicKey, signature));
    // Prints: trueconst {
      generateKeyPairSync,
      createSign,
      createVerify,
    } = require('node:crypto');

    const { privateKey, publicKey } = generateKeyPairSync('rsa', {
      modulusLength: 2048,
    });

    const sign = createSign('SHA256');
    sign.update('some data to sign');
    sign.end();
    const signature = sign.sign(privateKey);

    const verify = createVerify('SHA256');
    verify.update('some data to sign');
    verify.end();
    console.log(verify.verify(publicKey, signature));
    // Prints: true

#### `sign.sign(privateKey[, outputEncoding])`#

History

Version | Changes
--- | ---
v15.0.0 | The privateKey can also be an ArrayBuffer and CryptoKey.
v13.2.0, v12.16.0 | This function now supports IEEE-P1363 DSA and ECDSA signatures.
v12.0.0 | This function now supports RSA-PSS keys.
v11.6.0 | This function now supports key objects.
v8.0.0 | Support for RSASSA-PSS and additional options was added.
v0.1.92 | Added in: v0.1.92

- `privateKey` <Object> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
  - `dsaEncoding` <string>
  - `padding` <integer>
  - `saltLength` <integer>
- `outputEncoding` <string> The encoding of the return value.
- Returns: <Buffer> | <string>

Calculates the signature on all the data passed through using either `sign.update()` or `sign.write()`.

If `privateKey` is not a `KeyObject`, this function behaves as if `privateKey` had been passed to `crypto.createPrivateKey()`. If it is an object, the following additional properties can be passed:

- `dsaEncoding` <string> For DSA and ECDSA, this option specifies the format of the generated signature. It can be one of the following:

  - `'der'` (default): DER-encoded ASN.1 signature structure encoding `(r, s)`.
  - `'ieee-p1363'`: Signature format `r || s` as proposed in IEEE-P1363.

- `padding` <integer> Optional padding value for RSA, one of the following:

  - `crypto.constants.RSA_PKCS1_PADDING` (default)
  - `crypto.constants.RSA_PKCS1_PSS_PADDING`

  `RSA_PKCS1_PSS_PADDING` will use MGF1 with the same hash function used to sign the message as specified in section 3.1 of RFC 4055, unless an MGF1 hash function has been specified as part of the key in compliance with section 3.3 of RFC 4055.

- `saltLength` <integer> Salt length for when padding is `RSA_PKCS1_PSS_PADDING`. The special value `crypto.constants.RSA_PSS_SALTLEN_DIGEST` sets the salt length to the digest size, `crypto.constants.RSA_PSS_SALTLEN_MAX_SIGN` (default) sets it to the maximum permissible value.

If `outputEncoding` is provided a string is returned; otherwise a `Buffer` is returned.

The `Sign` object can not be again used after `sign.sign()` method has been called. Multiple calls to `sign.sign()` will result in an error being thrown.

#### `sign.update(data[, inputEncoding])`#

History

Version | Changes
--- | ---
v6.0.0 | The default `inputEncoding` changed from `binary` to `utf8`.
v0.1.92 | Added in: v0.1.92

- `data` <string> | <Buffer> | <TypedArray> | <DataView>
- `inputEncoding` <string> The encoding of the `data` string.

Updates the `Sign` content with the given `data`, the encoding of which is given in `inputEncoding`. If `encoding` is not provided, and the `data` is a string, an encoding of `'utf8'` is enforced. If `data` is a `Buffer`, `TypedArray`, or `DataView`, then `inputEncoding` is ignored.

This can be called many times with new data as it is streamed.

### Class: `Verify`#

Added in: v0.1.92

- Extends: <stream.Writable>

The `Verify` class is a utility for verifying signatures. It can be used in one of two ways:

- As a writable stream where written data is used to validate against the supplied signature, or
- Using the `verify.update()` and `verify.verify()` methods to verify the signature.

The `crypto.createVerify()` method is used to create `Verify` instances. `Verify` objects are not to be created directly using the `new` keyword.

See `Sign` for examples.

#### `verify.update(data[, inputEncoding])`#

History

Version | Changes
--- | ---
v6.0.0 | The default `inputEncoding` changed from `binary` to `utf8`.
v0.1.92 | Added in: v0.1.92

- `data` <string> | <Buffer> | <TypedArray> | <DataView>
- `inputEncoding` <string> The encoding of the `data` string.

Updates the `Verify` content with the given `data`, the encoding of which is given in `inputEncoding`. If `inputEncoding` is not provided, and the `data` is a string, an encoding of `'utf8'` is enforced. If `data` is a `Buffer`, `TypedArray`, or `DataView`, then `inputEncoding` is ignored.

This can be called many times with new data as it is streamed.

#### `verify.verify(object, signature[, signatureEncoding])`#

History

Version | Changes
--- | ---
v15.0.0 | The object can also be an ArrayBuffer and CryptoKey.
v13.2.0, v12.16.0 | This function now supports IEEE-P1363 DSA and ECDSA signatures.
v12.0.0 | This function now supports RSA-PSS keys.
v11.7.0 | The key can now be a private key.
v8.0.0 | Support for RSASSA-PSS and additional options was added.
v0.1.92 | Added in: v0.1.92

- `object` <Object> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
  - `dsaEncoding` <string>
  - `padding` <integer>
  - `saltLength` <integer>
- `signature` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `signatureEncoding` <string> The encoding of the `signature` string.
- Returns: <boolean> `true` or `false` depending on the validity of the signature for the data and public key.

Verifies the provided data using the given `object` and `signature`.

If `object` is not a `KeyObject`, this function behaves as if `object` had been passed to `crypto.createPublicKey()`. If it is an object, the following additional properties can be passed:

- `dsaEncoding` <string> For DSA and ECDSA, this option specifies the format of the signature. It can be one of the following:

  - `'der'` (default): DER-encoded ASN.1 signature structure encoding `(r, s)`.
  - `'ieee-p1363'`: Signature format `r || s` as proposed in IEEE-P1363.

- `padding` <integer> Optional padding value for RSA, one of the following:

  - `crypto.constants.RSA_PKCS1_PADDING` (default)
  - `crypto.constants.RSA_PKCS1_PSS_PADDING`

  `RSA_PKCS1_PSS_PADDING` will use MGF1 with the same hash function used to verify the message as specified in section 3.1 of RFC 4055, unless an MGF1 hash function has been specified as part of the key in compliance with section 3.3 of RFC 4055.

- `saltLength` <integer> Salt length for when padding is `RSA_PKCS1_PSS_PADDING`. The special value `crypto.constants.RSA_PSS_SALTLEN_DIGEST` sets the salt length to the digest size, `crypto.constants.RSA_PSS_SALTLEN_AUTO` (default) causes it to be determined automatically.

The `signature` argument is the previously calculated signature for the data, in the `signatureEncoding`. If a `signatureEncoding` is specified, the `signature` is expected to be a string; otherwise `signature` is expected to be a `Buffer`, `TypedArray`, or `DataView`.

The `verify` object can not be used again after `verify.verify()` has been called. Multiple calls to `verify.verify()` will result in an error being thrown.

Because public keys can be derived from private keys, a private key may be passed instead of a public key.

### Class: `X509Certificate`#

Added in: v15.6.0

Encapsulates an X509 certificate and provides read-only access to its information.

    const { X509Certificate } = await import('node:crypto');

    const x509 = new X509Certificate('{... pem encoded cert ...}');

    console.log(x509.subject);const { X509Certificate } = require('node:crypto');

    const x509 = new X509Certificate('{... pem encoded cert ...}');

    console.log(x509.subject);

#### `new X509Certificate(buffer)`#

Added in: v15.6.0

- `buffer` <string> | <TypedArray> | <Buffer> | <DataView> A PEM or DER encoded X509 Certificate.

#### `x509.ca`#

Added in: v15.6.0

- Type: <boolean> Will be `true` if this is a Certificate Authority (CA) certificate.

#### `x509.checkEmail(email[, options])`#

History

Version | Changes
--- | ---
v18.0.0 | The subject option now defaults to `'default'`.
v17.5.0, v16.15.0 | The subject option can now be set to `'default'`.
v17.5.0, v16.14.1 | The `wildcards`, `partialWildcards`, `multiLabelWildcards`, and `singleLabelSubdomains` options have been removed since they had no effect.
v15.6.0 | Added in: v15.6.0

- `email` <string>
- `options` <Object>
  - `subject` <string> `'default'`, `'always'`, or `'never'`. Default: `'default'`.
- Returns: <string> | <undefined> Returns `email` if the certificate matches, `undefined` if it does not.

Checks whether the certificate matches the given email address.

If the `'subject'` option is undefined or set to `'default'`, the certificate subject is only considered if the subject alternative name extension either does not exist or does not contain any email addresses.

If the `'subject'` option is set to `'always'` and if the subject alternative name extension either does not exist or does not contain a matching email address, the certificate subject is considered.

If the `'subject'` option is set to `'never'`, the certificate subject is never considered, even if the certificate contains no subject alternative names.

#### `x509.checkHost(name[, options])`#

History

Version | Changes
--- | ---
v18.0.0 | The subject option now defaults to `'default'`.
v17.5.0, v16.15.0 | The subject option can now be set to `'default'`.
v15.6.0 | Added in: v15.6.0

- `name` <string>
- `options` <Object>
  - `subject` <string> `'default'`, `'always'`, or `'never'`. Default: `'default'`.
  - `wildcards` <boolean> Default: `true`.
  - `partialWildcards` <boolean> Default: `true`.
  - `multiLabelWildcards` <boolean> Default: `false`.
  - `singleLabelSubdomains` <boolean> Default: `false`.
- Returns: <string> | <undefined> Returns a subject name that matches `name`, or `undefined` if no subject name matches `name`.

Checks whether the certificate matches the given host name.

If the certificate matches the given host name, the matching subject name is returned. The returned name might be an exact match (e.g., `foo.example.com`) or it might contain wildcards (e.g., `*.example.com`). Because host name comparisons are case-insensitive, the returned subject name might also differ from the given `name` in capitalization.

If the `'subject'` option is undefined or set to `'default'`, the certificate subject is only considered if the subject alternative name extension either does not exist or does not contain any DNS names. This behavior is consistent with RFC 2818 ("HTTP Over TLS").

If the `'subject'` option is set to `'always'` and if the subject alternative name extension either does not exist or does not contain a matching DNS name, the certificate subject is considered.

If the `'subject'` option is set to `'never'`, the certificate subject is never considered, even if the certificate contains no subject alternative names.

#### `x509.checkIP(ip)`#

History

Version | Changes
--- | ---
v17.5.0, v16.14.1 | The `options` argument has been removed since it had no effect.
v15.6.0 | Added in: v15.6.0

- `ip` <string>
- Returns: <string> | <undefined> Returns `ip` if the certificate matches, `undefined` if it does not.

Checks whether the certificate matches the given IP address (IPv4 or IPv6).

Only RFC 5280 `iPAddress` subject alternative names are considered, and they must match the given `ip` address exactly. Other subject alternative names as well as the subject field of the certificate are ignored.

#### `x509.checkIssued(otherCert)`#

Added in: v15.6.0

- `otherCert` <X509Certificate>
- Returns: <boolean>

Checks whether this certificate was issued by the given `otherCert`.

#### `x509.checkPrivateKey(privateKey)`#

Added in: v15.6.0

- `privateKey` <KeyObject> A private key.
- Returns: <boolean>

Checks whether the public key for this certificate is consistent with the given private key.

#### `x509.fingerprint`#

Added in: v15.6.0

- Type: <string>

The SHA-1 fingerprint of this certificate.

Because SHA-1 is cryptographically broken and because the security of SHA-1 is significantly worse than that of algorithms that are commonly used to sign certificates, consider using `x509.fingerprint256` instead.

#### `x509.fingerprint256`#

Added in: v15.6.0

- Type: <string>

The SHA-256 fingerprint of this certificate.

#### `x509.fingerprint512`#

Added in: v17.2.0, v16.14.0

- Type: <string>

The SHA-512 fingerprint of this certificate.

Because computing the SHA-256 fingerprint is usually faster and because it is only half the size of the SHA-512 fingerprint, `x509.fingerprint256` may be a better choice. While SHA-512 presumably provides a higher level of security in general, the security of SHA-256 matches that of most algorithms that are commonly used to sign certificates.

#### `x509.infoAccess`#

History

Version | Changes
--- | ---
v17.3.1, v16.13.2 | Parts of this string may be encoded as JSON string literals in response to CVE-2021-44532.
v15.6.0 | Added in: v15.6.0

- Type: <string>

A textual representation of the certificate's authority information access extension.

This is a line feed separated list of access descriptions. Each line begins with the access method and the kind of the access location, followed by a colon and the value associated with the access location.

After the prefix denoting the access method and the kind of the access location, the remainder of each line might be enclosed in quotes to indicate that the value is a JSON string literal. For backward compatibility, Node.js only uses JSON string literals within this property when necessary to avoid ambiguity. Third-party code should be prepared to handle both possible entry formats.

#### `x509.issuer`#

Added in: v15.6.0

- Type: <string>

The issuer identification included in this certificate.

#### `x509.issuerCertificate`#

Added in: v15.9.0

- Type: <X509Certificate>

The issuer certificate or `undefined` if the issuer certificate is not available.

#### `x509.keyUsage`#

Added in: v15.6.0

- Type: <string[]>

An array detailing the key usages for this certificate.

#### `x509.publicKey`#

Added in: v15.6.0

- Type: <KeyObject>

The public key <KeyObject> for this certificate.

#### `x509.raw`#

Added in: v15.6.0

- Type: <Buffer>

A `Buffer` containing the DER encoding of this certificate.

#### `x509.serialNumber`#

Added in: v15.6.0

- Type: <string>

The serial number of this certificate.

Serial numbers are assigned by certificate authorities and do not uniquely identify certificates. Consider using `x509.fingerprint256` as a unique identifier instead.

#### `x509.subject`#

Added in: v15.6.0

- Type: <string>

The complete subject of this certificate.

#### `x509.subjectAltName`#

History

Version | Changes
--- | ---
v17.3.1, v16.13.2 | Parts of this string may be encoded as JSON string literals in response to CVE-2021-44532.
v15.6.0 | Added in: v15.6.0

- Type: <string>

The subject alternative name specified for this certificate.

This is a comma-separated list of subject alternative names. Each entry begins with a string identifying the kind of the subject alternative name followed by a colon and the value associated with the entry.

Earlier versions of Node.js incorrectly assumed that it is safe to split this property at the two-character sequence `', '` (see CVE-2021-44532). However, both malicious and legitimate certificates can contain subject alternative names that include this sequence when represented as a string.

After the prefix denoting the type of the entry, the remainder of each entry might be enclosed in quotes to indicate that the value is a JSON string literal. For backward compatibility, Node.js only uses JSON string literals within this property when necessary to avoid ambiguity. Third-party code should be prepared to handle both possible entry formats.

#### `x509.toJSON()`#

Added in: v15.6.0

- Type: <string>

There is no standard JSON encoding for X509 certificates. The `toJSON()` method returns a string containing the PEM encoded certificate.

#### `x509.toLegacyObject()`#

Added in: v15.6.0

- Type: <Object>

Returns information about this certificate using the legacy certificate object encoding.

#### `x509.toString()`#

Added in: v15.6.0

- Type: <string>

Returns the PEM-encoded certificate.

#### `x509.validFrom`#

Added in: v15.6.0

- Type: <string>

The date/time from which this certificate is considered valid.

#### `x509.validTo`#

Added in: v15.6.0

- Type: <string>

The date/time until which this certificate is considered valid.

#### `x509.verify(publicKey)`#

Added in: v15.6.0

- `publicKey` <KeyObject> A public key.
- Returns: <boolean>

Verifies that this certificate was signed by the given public key. Does not perform any other validation checks on the certificate.

### `node:crypto` module methods and properties#

#### `crypto.constants`#

Added in: v6.3.0

- Returns: <Object> An object containing commonly used constants for crypto and security related operations. The specific constants currently defined are described in Crypto constants.

#### `crypto.DEFAULT_ENCODING`#

Added in: v0.9.3 Deprecated since: v10.0.0

Stability: 0 - Deprecated

The default encoding to use for functions that can take either strings or buffers. The default value is `'buffer'`, which makes methods default to `Buffer` objects.

The `crypto.DEFAULT_ENCODING` mechanism is provided for backward compatibility with legacy programs that expect `'latin1'` to be the default encoding.

New applications should expect the default to be `'buffer'`.

This property is deprecated.

#### `crypto.fips`#

Added in: v6.0.0 Deprecated since: v10.0.0

Stability: 0 - Deprecated

Property for checking and controlling whether a FIPS compliant crypto provider is currently in use. Setting to true requires a FIPS build of Node.js.

This property is deprecated. Please use `crypto.setFips()` and `crypto.getFips()` instead.

#### `crypto.checkPrime(candidate[, options[, callback]])`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v15.8.0 | Added in: v15.8.0

- `candidate` <ArrayBuffer> | <SharedArrayBuffer> | <TypedArray> | <Buffer> | <DataView> | <bigint> A possible prime encoded as a sequence of big endian octets of arbitrary length.
- `options` <Object>
  - `checks` <number> The number of Miller-Rabin probabilistic primality iterations to perform. When the value is `0` (zero), a number of checks is used that yields a false positive rate of at most 2-64 for random input. Care must be used when selecting a number of checks. Refer to the OpenSSL documentation for the `BN_is_prime_ex` function `nchecks` options for more details. Default: `0`
- `callback` <Function>
  - `err` <Error> Set to an <Error> object if an error occurred during check.
  - `result` <boolean> `true` if the candidate is a prime with an error probability less than `0.25 ** options.checks`.

Checks the primality of the `candidate`.

#### `crypto.checkPrimeSync(candidate[, options])`#

Added in: v15.8.0

- `candidate` <ArrayBuffer> | <SharedArrayBuffer> | <TypedArray> | <Buffer> | <DataView> | <bigint> A possible prime encoded as a sequence of big endian octets of arbitrary length.
- `options` <Object>
  - `checks` <number> The number of Miller-Rabin probabilistic primality iterations to perform. When the value is `0` (zero), a number of checks is used that yields a false positive rate of at most 2-64 for random input. Care must be used when selecting a number of checks. Refer to the OpenSSL documentation for the `BN_is_prime_ex` function `nchecks` options for more details. Default: `0`
- Returns: <boolean> `true` if the candidate is a prime with an error probability less than `0.25 ** options.checks`.

Checks the primality of the `candidate`.

#### `crypto.createCipher(algorithm, password[, options])`#

History

Version | Changes
--- | ---
v17.9.0 | The `authTagLength` option is now optional when using the `chacha20-poly1305` cipher and defaults to 16 bytes.
v15.0.0 | The password argument can be an ArrayBuffer and is limited to a maximum of 2 ** 31 - 1 bytes.
v10.10.0 | Ciphers in OCB mode are now supported.
v10.2.0 | The `authTagLength` option can now be used to produce shorter authentication tags in GCM mode and defaults to 16 bytes.
v10.0.0 | Deprecated since: v10.0.0
v0.1.94 | Added in: v0.1.94

Stability: 0 - Deprecated: Use `crypto.createCipheriv()` instead.

- `algorithm` <string>
- `password` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `options` <Object> `stream.transform` options
- Returns: <Cipher>

Creates and returns a `Cipher` object that uses the given `algorithm` and `password`.

The `options` argument controls stream behavior and is optional except when a cipher in CCM or OCB mode (e.g. `'aes-128-ccm'`) is used. In that case, the `authTagLength` option is required and specifies the length of the authentication tag in bytes, see CCM mode. In GCM mode, the `authTagLength` option is not required but can be used to set the length of the authentication tag that will be returned by `getAuthTag()` and defaults to 16 bytes. For `chacha20-poly1305`, the `authTagLength` option defaults to 16 bytes.

The `algorithm` is dependent on OpenSSL, examples are `'aes192'`, etc. On recent OpenSSL releases, `openssl list -cipher-algorithms` will display the available cipher algorithms.

The `password` is used to derive the cipher key and initialization vector (IV). The value must be either a `'latin1'` encoded string, a `Buffer`, a `TypedArray`, or a `DataView`.

The implementation of `crypto.createCipher()` derives keys using the OpenSSL function `EVP_BytesToKey` with the digest algorithm set to MD5, one iteration, and no salt. The lack of salt allows dictionary attacks as the same password always creates the same key. The low iteration count and non-cryptographically secure hash algorithm allow passwords to be tested very rapidly.

In line with OpenSSL's recommendation to use a more modern algorithm instead of `EVP_BytesToKey` it is recommended that developers derive a key and IV on their own using `crypto.scrypt()` and to use `crypto.createCipheriv()` to create the `Cipher` object. Users should not use ciphers with counter mode (e.g. CTR, GCM, or CCM) in `crypto.createCipher()`. A warning is emitted when they are used in order to avoid the risk of IV reuse that causes vulnerabilities. For the case when IV is reused in GCM, see Nonce-Disrespecting Adversaries for details.

#### `crypto.createCipheriv(algorithm, key, iv[, options])`#

History

Version | Changes
--- | ---
v17.9.0 | The `authTagLength` option is now optional when using the `chacha20-poly1305` cipher and defaults to 16 bytes.
v15.0.0 | The password and iv arguments can be an ArrayBuffer and are each limited to a maximum of 2 ** 31 - 1 bytes.
v11.6.0 | The `key` argument can now be a `KeyObject`.
v11.2.0, v10.17.0 | The cipher `chacha20-poly1305` (the IETF variant of ChaCha20-Poly1305) is now supported.
v10.10.0 | Ciphers in OCB mode are now supported.
v10.2.0 | The `authTagLength` option can now be used to produce shorter authentication tags in GCM mode and defaults to 16 bytes.
v9.9.0 | The `iv` parameter may now be `null` for ciphers which do not need an initialization vector.
v0.1.94 | Added in: v0.1.94

- `algorithm` <string>
- `key` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
- `iv` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <null>
- `options` <Object> `stream.transform` options
- Returns: <Cipher>

Creates and returns a `Cipher` object, with the given `algorithm`, `key` and initialization vector (`iv`).

The `options` argument controls stream behavior and is optional except when a cipher in CCM or OCB mode (e.g. `'aes-128-ccm'`) is used. In that case, the `authTagLength` option is required and specifies the length of the authentication tag in bytes, see CCM mode. In GCM mode, the `authTagLength` option is not required but can be used to set the length of the authentication tag that will be returned by `getAuthTag()` and defaults to 16 bytes. For `chacha20-poly1305`, the `authTagLength` option defaults to 16 bytes.

The `algorithm` is dependent on OpenSSL, examples are `'aes192'`, etc. On recent OpenSSL releases, `openssl list -cipher-algorithms` will display the available cipher algorithms.

The `key` is the raw key used by the `algorithm` and `iv` is an initialization vector. Both arguments must be `'utf8'` encoded strings, Buffers, `TypedArray`, or `DataView`s. The `key` may optionally be a `KeyObject` of type `secret`. If the cipher does not need an initialization vector, `iv` may be `null`.

When passing strings for `key` or `iv`, please consider caveats when using strings as inputs to cryptographic APIs.

Initialization vectors should be unpredictable and unique; ideally, they will be cryptographically random. They do not have to be secret: IVs are typically just added to ciphertext messages unencrypted. It may sound contradictory that something has to be unpredictable and unique, but does not have to be secret; remember that an attacker must not be able to predict ahead of time what a given IV will be.

#### `crypto.createDecipher(algorithm, password[, options])`#

History

Version | Changes
--- | ---
v17.9.0 | The `authTagLength` option is now optional when using the `chacha20-poly1305` cipher and defaults to 16 bytes.
v10.10.0 | Ciphers in OCB mode are now supported.
v10.0.0 | Deprecated since: v10.0.0
v0.1.94 | Added in: v0.1.94

Stability: 0 - Deprecated: Use `crypto.createDecipheriv()` instead.

- `algorithm` <string>
- `password` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `options` <Object> `stream.transform` options
- Returns: <Decipher>

Creates and returns a `Decipher` object that uses the given `algorithm` and `password` (key).

The `options` argument controls stream behavior and is optional except when a cipher in CCM or OCB mode (e.g. `'aes-128-ccm'`) is used. In that case, the `authTagLength` option is required and specifies the length of the authentication tag in bytes, see CCM mode. For `chacha20-poly1305`, the `authTagLength` option defaults to 16 bytes.

The implementation of `crypto.createDecipher()` derives keys using the OpenSSL function `EVP_BytesToKey` with the digest algorithm set to MD5, one iteration, and no salt. The lack of salt allows dictionary attacks as the same password always creates the same key. The low iteration count and non-cryptographically secure hash algorithm allow passwords to be tested very rapidly.

In line with OpenSSL's recommendation to use a more modern algorithm instead of `EVP_BytesToKey` it is recommended that developers derive a key and IV on their own using `crypto.scrypt()` and to use `crypto.createDecipheriv()` to create the `Decipher` object.

#### `crypto.createDecipheriv(algorithm, key, iv[, options])`#

History

Version | Changes
--- | ---
v17.9.0 | The `authTagLength` option is now optional when using the `chacha20-poly1305` cipher and defaults to 16 bytes.
v11.6.0 | The `key` argument can now be a `KeyObject`.
v11.2.0, v10.17.0 | The cipher `chacha20-poly1305` (the IETF variant of ChaCha20-Poly1305) is now supported.
v10.10.0 | Ciphers in OCB mode are now supported.
v10.2.0 | The `authTagLength` option can now be used to restrict accepted GCM authentication tag lengths.
v9.9.0 | The `iv` parameter may now be `null` for ciphers which do not need an initialization vector.
v0.1.94 | Added in: v0.1.94

- `algorithm` <string>
- `key` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
- `iv` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <null>
- `options` <Object> `stream.transform` options
- Returns: <Decipher>

Creates and returns a `Decipher` object that uses the given `algorithm`, `key` and initialization vector (`iv`).

The `options` argument controls stream behavior and is optional except when a cipher in CCM or OCB mode (e.g. `'aes-128-ccm'`) is used. In that case, the `authTagLength` option is required and specifies the length of the authentication tag in bytes, see CCM mode. In GCM mode, the `authTagLength` option is not required but can be used to restrict accepted authentication tags to those with the specified length. For `chacha20-poly1305`, the `authTagLength` option defaults to 16 bytes.

The `algorithm` is dependent on OpenSSL, examples are `'aes192'`, etc. On recent OpenSSL releases, `openssl list -cipher-algorithms` will display the available cipher algorithms.

The `key` is the raw key used by the `algorithm` and `iv` is an initialization vector. Both arguments must be `'utf8'` encoded strings, Buffers, `TypedArray`, or `DataView`s. The `key` may optionally be a `KeyObject` of type `secret`. If the cipher does not need an initialization vector, `iv` may be `null`.

When passing strings for `key` or `iv`, please consider caveats when using strings as inputs to cryptographic APIs.

Initialization vectors should be unpredictable and unique; ideally, they will be cryptographically random. They do not have to be secret: IVs are typically just added to ciphertext messages unencrypted. It may sound contradictory that something has to be unpredictable and unique, but does not have to be secret; remember that an attacker must not be able to predict ahead of time what a given IV will be.

#### `crypto.createDiffieHellman(prime[, primeEncoding][, generator][, generatorEncoding])`#

History

Version | Changes
--- | ---
v8.0.0 | The `prime` argument can be any `TypedArray` or `DataView` now.
v8.0.0 | The `prime` argument can be a `Uint8Array` now.
v6.0.0 | The default for the encoding parameters changed from `binary` to `utf8`.
v0.11.12 | Added in: v0.11.12

- `prime` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `primeEncoding` <string> The encoding of the `prime` string.
- `generator` <number> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> Default: `2`
- `generatorEncoding` <string> The encoding of the `generator` string.
- Returns: <DiffieHellman>

Creates a `DiffieHellman` key exchange object using the supplied `prime` and an optional specific `generator`.

The `generator` argument can be a number, string, or `Buffer`. If `generator` is not specified, the value `2` is used.

If `primeEncoding` is specified, `prime` is expected to be a string; otherwise a `Buffer`, `TypedArray`, or `DataView` is expected.

If `generatorEncoding` is specified, `generator` is expected to be a string; otherwise a number, `Buffer`, `TypedArray`, or `DataView` is expected.

#### `crypto.createDiffieHellman(primeLength[, generator])`#

Added in: v0.5.0

- `primeLength` <number>
- `generator` <number> Default: `2`
- Returns: <DiffieHellman>

Creates a `DiffieHellman` key exchange object and generates a prime of `primeLength` bits using an optional specific numeric `generator`. If `generator` is not specified, the value `2` is used.

#### `crypto.createDiffieHellmanGroup(name)`#

Added in: v0.9.3

- `name` <string>
- Returns: <DiffieHellmanGroup>

An alias for `crypto.getDiffieHellman()`

#### `crypto.createECDH(curveName)`#

Added in: v0.11.14

- `curveName` <string>
- Returns: <ECDH>

Creates an Elliptic Curve Diffie-Hellman (`ECDH`) key exchange object using a predefined curve specified by the `curveName` string. Use `crypto.getCurves()` to obtain a list of available curve names. On recent OpenSSL releases, `openssl ecparam -list_curves` will also display the name and description of each available elliptic curve.

#### `crypto.createHash(algorithm[, options])`#

History

Version | Changes
--- | ---
v12.8.0 | The `outputLength` option was added for XOF hash functions.
v0.1.92 | Added in: v0.1.92

- `algorithm` <string>
- `options` <Object> `stream.transform` options
- Returns: <Hash>

Creates and returns a `Hash` object that can be used to generate hash digests using the given `algorithm`. Optional `options` argument controls stream behavior. For XOF hash functions such as `'shake256'`, the `outputLength` option can be used to specify the desired output length in bytes.

The `algorithm` is dependent on the available algorithms supported by the version of OpenSSL on the platform. Examples are `'sha256'`, `'sha512'`, etc. On recent releases of OpenSSL, `openssl list -digest-algorithms` will display the available digest algorithms.

Example: generating the sha256 sum of a file

    import {
      createReadStream
    } from 'fs';
    import { argv } from 'node:process';
    const {
      createHash
    } = await import('node:crypto');

    const filename = argv[2];

    const hash = createHash('sha256');

    const input = createReadStream(filename);
    input.on('readable', () => {
      // Only one element is going to be produced by the
      // hash stream.
      const data = input.read();
      if (data)
        hash.update(data);
      else {
        console.log(`${hash.digest('hex')} ${filename}`);
      }
    });const {
      createReadStream,
    } = require('node:fs');
    const {
      createHash,
    } = require('node:crypto');
    const { argv } = require('node:process');

    const filename = argv[2];

    const hash = createHash('sha256');

    const input = createReadStream(filename);
    input.on('readable', () => {
      // Only one element is going to be produced by the
      // hash stream.
      const data = input.read();
      if (data)
        hash.update(data);
      else {
        console.log(`${hash.digest('hex')} ${filename}`);
      }
    });

#### `crypto.createHmac(algorithm, key[, options])`#

History

Version | Changes
--- | ---
v15.0.0 | The key can also be an ArrayBuffer or CryptoKey. The encoding option was added. The key cannot contain more than 2 ** 32 - 1 bytes.
v11.6.0 | The `key` argument can now be a `KeyObject`.
v0.1.94 | Added in: v0.1.94

- `algorithm` <string>
- `key` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
- `options` <Object> `stream.transform` options
  - `encoding` <string> The string encoding to use when `key` is a string.
- Returns: <Hmac>

Creates and returns an `Hmac` object that uses the given `algorithm` and `key`. Optional `options` argument controls stream behavior.

The `algorithm` is dependent on the available algorithms supported by the version of OpenSSL on the platform. Examples are `'sha256'`, `'sha512'`, etc. On recent releases of OpenSSL, `openssl list -digest-algorithms` will display the available digest algorithms.

The `key` is the HMAC key used to generate the cryptographic HMAC hash. If it is a `KeyObject`, its type must be `secret`.

Example: generating the sha256 HMAC of a file

    import {
      createReadStream
    } from 'fs';
    import { argv } from 'node:process';
    const {
      createHmac
    } = await import('node:crypto');

    const filename = argv[2];

    const hmac = createHmac('sha256', 'a secret');

    const input = createReadStream(filename);
    input.on('readable', () => {
      // Only one element is going to be produced by the
      // hash stream.
      const data = input.read();
      if (data)
        hmac.update(data);
      else {
        console.log(`${hmac.digest('hex')} ${filename}`);
      }
    });const {
      createReadStream,
    } = require('node:fs');
    const {
      createHmac,
    } = require('node:crypto');
    const { argv } = require('node:process');

    const filename = argv[2];

    const hmac = createHmac('sha256', 'a secret');

    const input = createReadStream(filename);
    input.on('readable', () => {
      // Only one element is going to be produced by the
      // hash stream.
      const data = input.read();
      if (data)
        hmac.update(data);
      else {
        console.log(`${hmac.digest('hex')} ${filename}`);
      }
    });

#### `crypto.createPrivateKey(key)`#

History

Version | Changes
--- | ---
v15.12.0 | The key can also be a JWK object.
v15.0.0 | The key can also be an ArrayBuffer. The encoding option was added. The key cannot contain more than 2 ** 32 - 1 bytes.
v11.6.0 | Added in: v11.6.0

- `key` <Object> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
  - `key`: <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <Object> The key material, either in PEM, DER, or JWK format.
  - `format`: <string> Must be `'pem'`, `'der'`, or '`'jwk'`. Default: `'pem'`.
  - `type`: <string> Must be `'pkcs1'`, `'pkcs8'` or `'sec1'`. This option is required only if the `format` is `'der'` and ignored otherwise.
  - `passphrase`: <string> | <Buffer> The passphrase to use for decryption.
  - `encoding`: <string> The string encoding to use when `key` is a string.
- Returns: <KeyObject>

Creates and returns a new key object containing a private key. If `key` is a string or `Buffer`, `format` is assumed to be `'pem'`; otherwise, `key` must be an object with the properties described above.

If the private key is encrypted, a `passphrase` must be specified. The length of the passphrase is limited to 1024 bytes.

#### `crypto.createPublicKey(key)`#

History

Version | Changes
--- | ---
v15.12.0 | The key can also be a JWK object.
v15.0.0 | The key can also be an ArrayBuffer. The encoding option was added. The key cannot contain more than 2 ** 32 - 1 bytes.
v11.13.0 | The `key` argument can now be a `KeyObject` with type `private`.
v11.7.0 | The `key` argument can now be a private key.
v11.6.0 | Added in: v11.6.0

- `key` <Object> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
  - `key`: <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <Object> The key material, either in PEM, DER, or JWK format.
  - `format`: <string> Must be `'pem'`, `'der'`, or `'jwk'`. Default: `'pem'`.
  - `type`: <string> Must be `'pkcs1'` or `'spki'`. This option is required only if the `format` is `'der'` and ignored otherwise.
  - `encoding` <string> The string encoding to use when `key` is a string.
- Returns: <KeyObject>

Creates and returns a new key object containing a public key. If `key` is a string or `Buffer`, `format` is assumed to be `'pem'`; if `key` is a `KeyObject` with type `'private'`, the public key is derived from the given private key; otherwise, `key` must be an object with the properties described above.

If the format is `'pem'`, the `'key'` may also be an X.509 certificate.

Because public keys can be derived from private keys, a private key may be passed instead of a public key. In that case, this function behaves as if `crypto.createPrivateKey()` had been called, except that the type of the returned `KeyObject` will be `'public'` and that the private key cannot be extracted from the returned `KeyObject`. Similarly, if a `KeyObject` with type `'private'` is given, a new `KeyObject` with type `'public'` will be returned and it will be impossible to extract the private key from the returned object.

#### `crypto.createSecretKey(key[, encoding])`#

History

Version | Changes
--- | ---
v15.0.0 | The key can also be an ArrayBuffer or string. The encoding argument was added. The key cannot contain more than 2 ** 32 - 1 bytes.
v11.6.0 | Added in: v11.6.0

- `key` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `encoding` <string> The string encoding when `key` is a string.
- Returns: <KeyObject>

Creates and returns a new key object containing a secret key for symmetric encryption or `Hmac`.

#### `crypto.createSign(algorithm[, options])`#

Added in: v0.1.92

- `algorithm` <string>
- `options` <Object> `stream.Writable` options
- Returns: <Sign>

Creates and returns a `Sign` object that uses the given `algorithm`. Use `crypto.getHashes()` to obtain the names of the available digest algorithms. Optional `options` argument controls the `stream.Writable` behavior.

In some cases, a `Sign` instance can be created using the name of a signature algorithm, such as `'RSA-SHA256'`, instead of a digest algorithm. This will use the corresponding digest algorithm. This does not work for all signature algorithms, such as `'ecdsa-with-SHA256'`, so it is best to always use digest algorithm names.

#### `crypto.createVerify(algorithm[, options])`#

Added in: v0.1.92

- `algorithm` <string>
- `options` <Object> `stream.Writable` options
- Returns: <Verify>

Creates and returns a `Verify` object that uses the given algorithm. Use `crypto.getHashes()` to obtain an array of names of the available signing algorithms. Optional `options` argument controls the `stream.Writable` behavior.

In some cases, a `Verify` instance can be created using the name of a signature algorithm, such as `'RSA-SHA256'`, instead of a digest algorithm. This will use the corresponding digest algorithm. This does not work for all signature algorithms, such as `'ecdsa-with-SHA256'`, so it is best to always use digest algorithm names.

#### `crypto.diffieHellman(options)`#

Added in: v13.9.0, v12.17.0

- `options`: <Object>
  - `privateKey`: <KeyObject>
  - `publicKey`: <KeyObject>
- Returns: <Buffer>

Computes the Diffie-Hellman secret based on a `privateKey` and a `publicKey`. Both keys must have the same `asymmetricKeyType`, which must be one of `'dh'` (for Diffie-Hellman), `'ec'` (for ECDH), `'x448'`, or `'x25519'` (for ECDH-ES).

#### `crypto.generateKey(type, options, callback)`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v15.0.0 | Added in: v15.0.0

- `type`: <string> The intended use of the generated secret key. Currently accepted values are `'hmac'` and `'aes'`.
- `options`: <Object>
  - `length`: <number> The bit length of the key to generate. This must be a value greater than 0.
    - If `type` is `'hmac'`, the minimum is 8, and the maximum length is 231-1. If the value is not a multiple of 8, the generated key will be truncated to `Math.floor(length / 8)`.
    - If `type` is `'aes'`, the length must be one of `128`, `192`, or `256`.
- `callback`: <Function>
  - `err`: <Error>
  - `key`: <KeyObject>

Asynchronously generates a new random secret key of the given `length`. The `type` will determine which validations will be performed on the `length`.

    const {
      generateKey
    } = await import('node:crypto');

    generateKey('hmac', { length: 64 }, (err, key) => {
      if (err) throw err;
      console.log(key.export().toString('hex'));  // 46e..........620
    });const {
      generateKey,
    } = require('node:crypto');

    generateKey('hmac', { length: 64 }, (err, key) => {
      if (err) throw err;
      console.log(key.export().toString('hex'));  // 46e..........620
    });

#### `crypto.generateKeyPair(type, options, callback)`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v16.10.0 | Add ability to define `RSASSA-PSS-params` sequence parameters for RSA-PSS keys pairs.
v13.9.0, v12.17.0 | Add support for Diffie-Hellman.
v12.0.0 | Add support for RSA-PSS key pairs.
v12.0.0 | Add ability to generate X25519 and X448 key pairs.
v12.0.0 | Add ability to generate Ed25519 and Ed448 key pairs.
v11.6.0 | The `generateKeyPair` and `generateKeyPairSync` functions now produce key objects if no encoding was specified.
v10.12.0 | Added in: v10.12.0

- `type`: <string> Must be `'rsa'`, `'rsa-pss'`, `'dsa'`, `'ec'`, `'ed25519'`, `'ed448'`, `'x25519'`, `'x448'`, or `'dh'`.
- `options`: <Object>
  - `modulusLength`: <number> Key size in bits (RSA, DSA).
  - `publicExponent`: <number> Public exponent (RSA). Default: `0x10001`.
  - `hashAlgorithm`: <string> Name of the message digest (RSA-PSS).
  - `mgf1HashAlgorithm`: <string> Name of the message digest used by MGF1 (RSA-PSS).
  - `saltLength`: <number> Minimal salt length in bytes (RSA-PSS).
  - `divisorLength`: <number> Size of `q` in bits (DSA).
  - `namedCurve`: <string> Name of the curve to use (EC).
  - `prime`: <Buffer> The prime parameter (DH).
  - `primeLength`: <number> Prime length in bits (DH).
  - `generator`: <number> Custom generator (DH). Default: `2`.
  - `groupName`: <string> Diffie-Hellman group name (DH). See `crypto.getDiffieHellman()`.
  - `publicKeyEncoding`: <Object> See `keyObject.export()`.
  - `privateKeyEncoding`: <Object> See `keyObject.export()`.
- `callback`: <Function>
  - `err`: <Error>
  - `publicKey`: <string> | <Buffer> | <KeyObject>
  - `privateKey`: <string> | <Buffer> | <KeyObject>

Generates a new asymmetric key pair of the given `type`. RSA, RSA-PSS, DSA, EC, Ed25519, Ed448, X25519, X448, and DH are currently supported.

If a `publicKeyEncoding` or `privateKeyEncoding` was specified, this function behaves as if `keyObject.export()` had been called on its result. Otherwise, the respective part of the key is returned as a `KeyObject`.

It is recommended to encode public keys as `'spki'` and private keys as `'pkcs8'` with encryption for long-term storage:

    const {
      generateKeyPair
    } = await import('node:crypto');

    generateKeyPair('rsa', {
      modulusLength: 4096,
      publicKeyEncoding: {
        type: 'spki',
        format: 'pem'
      },
      privateKeyEncoding: {
        type: 'pkcs8',
        format: 'pem',
        cipher: 'aes-256-cbc',
        passphrase: 'top secret'
      }
    }, (err, publicKey, privateKey) => {
      // Handle errors and use the generated key pair.
    });const {
      generateKeyPair,
    } = require('node:crypto');

    generateKeyPair('rsa', {
      modulusLength: 4096,
      publicKeyEncoding: {
        type: 'spki',
        format: 'pem'
      },
      privateKeyEncoding: {
        type: 'pkcs8',
        format: 'pem',
        cipher: 'aes-256-cbc',
        passphrase: 'top secret'
      }
    }, (err, publicKey, privateKey) => {
      // Handle errors and use the generated key pair.
    });

On completion, `callback` will be called with `err` set to `undefined` and `publicKey` / `privateKey` representing the generated key pair.

If this method is invoked as its `util.promisify()`ed version, it returns a `Promise` for an `Object` with `publicKey` and `privateKey` properties.

#### `crypto.generateKeyPairSync(type, options)`#

History

Version | Changes
--- | ---
v16.10.0 | Add ability to define `RSASSA-PSS-params` sequence parameters for RSA-PSS keys pairs.
v13.9.0, v12.17.0 | Add support for Diffie-Hellman.
v12.0.0 | Add support for RSA-PSS key pairs.
v12.0.0 | Add ability to generate X25519 and X448 key pairs.
v12.0.0 | Add ability to generate Ed25519 and Ed448 key pairs.
v11.6.0 | The `generateKeyPair` and `generateKeyPairSync` functions now produce key objects if no encoding was specified.
v10.12.0 | Added in: v10.12.0

- `type`: <string> Must be `'rsa'`, `'rsa-pss'`, `'dsa'`, `'ec'`, `'ed25519'`, `'ed448'`, `'x25519'`, `'x448'`, or `'dh'`.
- `options`: <Object>
  - `modulusLength`: <number> Key size in bits (RSA, DSA).
  - `publicExponent`: <number> Public exponent (RSA). Default: `0x10001`.
  - `hashAlgorithm`: <string> Name of the message digest (RSA-PSS).
  - `mgf1HashAlgorithm`: <string> Name of the message digest used by MGF1 (RSA-PSS).
  - `saltLength`: <number> Minimal salt length in bytes (RSA-PSS).
  - `divisorLength`: <number> Size of `q` in bits (DSA).
  - `namedCurve`: <string> Name of the curve to use (EC).
  - `prime`: <Buffer> The prime parameter (DH).
  - `primeLength`: <number> Prime length in bits (DH).
  - `generator`: <number> Custom generator (DH). Default: `2`.
  - `groupName`: <string> Diffie-Hellman group name (DH). See `crypto.getDiffieHellman()`.
  - `publicKeyEncoding`: <Object> See `keyObject.export()`.
  - `privateKeyEncoding`: <Object> See `keyObject.export()`.
- Returns: <Object>
  - `publicKey`: <string> | <Buffer> | <KeyObject>
  - `privateKey`: <string> | <Buffer> | <KeyObject>

Generates a new asymmetric key pair of the given `type`. RSA, RSA-PSS, DSA, EC, Ed25519, Ed448, X25519, X448, and DH are currently supported.

If a `publicKeyEncoding` or `privateKeyEncoding` was specified, this function behaves as if `keyObject.export()` had been called on its result. Otherwise, the respective part of the key is returned as a `KeyObject`.

When encoding public keys, it is recommended to use `'spki'`. When encoding private keys, it is recommended to use `'pkcs8'` with a strong passphrase, and to keep the passphrase confidential.

    const {
      generateKeyPairSync
    } = await import('node:crypto');

    const {
      publicKey,
      privateKey,
    } = generateKeyPairSync('rsa', {
      modulusLength: 4096,
      publicKeyEncoding: {
        type: 'spki',
        format: 'pem'
      },
      privateKeyEncoding: {
        type: 'pkcs8',
        format: 'pem',
        cipher: 'aes-256-cbc',
        passphrase: 'top secret'
      }
    });const {
      generateKeyPairSync,
    } = require('node:crypto');

    const {
      publicKey,
      privateKey,
    } = generateKeyPairSync('rsa', {
      modulusLength: 4096,
      publicKeyEncoding: {
        type: 'spki',
        format: 'pem'
      },
      privateKeyEncoding: {
        type: 'pkcs8',
        format: 'pem',
        cipher: 'aes-256-cbc',
        passphrase: 'top secret'
      }
    });

The return value `{ publicKey, privateKey }` represents the generated key pair. When PEM encoding was selected, the respective key will be a string, otherwise it will be a buffer containing the data encoded as DER.

#### `crypto.generateKeySync(type, options)`#

Added in: v15.0.0

- `type`: <string> The intended use of the generated secret key. Currently accepted values are `'hmac'` and `'aes'`.
- `options`: <Object>
  - `length`: <number> The bit length of the key to generate.
    - If `type` is `'hmac'`, the minimum is 8, and the maximum length is 231-1. If the value is not a multiple of 8, the generated key will be truncated to `Math.floor(length / 8)`.
    - If `type` is `'aes'`, the length must be one of `128`, `192`, or `256`.
- Returns: <KeyObject>

Synchronously generates a new random secret key of the given `length`. The `type` will determine which validations will be performed on the `length`.

    const {
      generateKeySync
    } = await import('node:crypto');

    const key = generateKeySync('hmac', { length: 64 });
    console.log(key.export().toString('hex'));  // e89..........41econst {
      generateKeySync,
    } = require('node:crypto');

    const key = generateKeySync('hmac', { length: 64 });
    console.log(key.export().toString('hex'));  // e89..........41e

#### `crypto.generatePrime(size[, options[, callback]])`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v15.8.0 | Added in: v15.8.0

- `size` <number> The size (in bits) of the prime to generate.
- `options` <Object>
  - `add` <ArrayBuffer> | <SharedArrayBuffer> | <TypedArray> | <Buffer> | <DataView> | <bigint>
  - `rem` <ArrayBuffer> | <SharedArrayBuffer> | <TypedArray> | <Buffer> | <DataView> | <bigint>
  - `safe` <boolean> Default: `false`.
  - `bigint` <boolean> When `true`, the generated prime is returned as a `bigint`.
- `callback` <Function>
  - `err` <Error>
  - `prime` <ArrayBuffer> | <bigint>

Generates a pseudorandom prime of `size` bits.

If `options.safe` is `true`, the prime will be a safe prime -- that is, `(prime - 1) / 2` will also be a prime.

The `options.add` and `options.rem` parameters can be used to enforce additional requirements, e.g., for Diffie-Hellman:

- If `options.add` and `options.rem` are both set, the prime will satisfy the condition that `prime % add = rem`.
- If only `options.add` is set and `options.safe` is not `true`, the prime will satisfy the condition that `prime % add = 1`.
- If only `options.add` is set and `options.safe` is set to `true`, the prime will instead satisfy the condition that `prime % add = 3`. This is necessary because `prime % add = 1` for `options.add > 2` would contradict the condition enforced by `options.safe`.
- `options.rem` is ignored if `options.add` is not given.

Both `options.add` and `options.rem` must be encoded as big-endian sequences if given as an `ArrayBuffer`, `SharedArrayBuffer`, `TypedArray`, `Buffer`, or `DataView`.

By default, the prime is encoded as a big-endian sequence of octets in an <ArrayBuffer>. If the `bigint` option is `true`, then a <bigint> is provided.

#### `crypto.generatePrimeSync(size[, options])`#

Added in: v15.8.0

- `size` <number> The size (in bits) of the prime to generate.
- `options` <Object>
  - `add` <ArrayBuffer> | <SharedArrayBuffer> | <TypedArray> | <Buffer> | <DataView> | <bigint>
  - `rem` <ArrayBuffer> | <SharedArrayBuffer> | <TypedArray> | <Buffer> | <DataView> | <bigint>
  - `safe` <boolean> Default: `false`.
  - `bigint` <boolean> When `true`, the generated prime is returned as a `bigint`.
- Returns: <ArrayBuffer> | <bigint>

Generates a pseudorandom prime of `size` bits.

If `options.safe` is `true`, the prime will be a safe prime -- that is, `(prime - 1) / 2` will also be a prime.

The `options.add` and `options.rem` parameters can be used to enforce additional requirements, e.g., for Diffie-Hellman:

- If `options.add` and `options.rem` are both set, the prime will satisfy the condition that `prime % add = rem`.
- If only `options.add` is set and `options.safe` is not `true`, the prime will satisfy the condition that `prime % add = 1`.
- If only `options.add` is set and `options.safe` is set to `true`, the prime will instead satisfy the condition that `prime % add = 3`. This is necessary because `prime % add = 1` for `options.add > 2` would contradict the condition enforced by `options.safe`.
- `options.rem` is ignored if `options.add` is not given.

Both `options.add` and `options.rem` must be encoded as big-endian sequences if given as an `ArrayBuffer`, `SharedArrayBuffer`, `TypedArray`, `Buffer`, or `DataView`.

By default, the prime is encoded as a big-endian sequence of octets in an <ArrayBuffer>. If the `bigint` option is `true`, then a <bigint> is provided.

#### `crypto.getCipherInfo(nameOrNid[, options])`#

Added in: v15.0.0

- `nameOrNid`: <string> | <number> The name or nid of the cipher to query.
- `options`: <Object>
  - `keyLength`: <number> A test key length.
  - `ivLength`: <number> A test IV length.
- Returns: <Object>
  - `name` <string> The name of the cipher
  - `nid` <number> The nid of the cipher
  - `blockSize` <number> The block size of the cipher in bytes. This property is omitted when `mode` is `'stream'`.
  - `ivLength` <number> The expected or default initialization vector length in bytes. This property is omitted if the cipher does not use an initialization vector.
  - `keyLength` <number> The expected or default key length in bytes.
  - `mode` <string> The cipher mode. One of `'cbc'`, `'ccm'`, `'cfb'`, `'ctr'`, `'ecb'`, `'gcm'`, `'ocb'`, `'ofb'`, `'stream'`, `'wrap'`, `'xts'`.

Returns information about a given cipher.

Some ciphers accept variable length keys and initialization vectors. By default, the `crypto.getCipherInfo()` method will return the default values for these ciphers. To test if a given key length or iv length is acceptable for given cipher, use the `keyLength` and `ivLength` options. If the given values are unacceptable, `undefined` will be returned.

#### `crypto.getCiphers()`#

Added in: v0.9.3

- Returns: <string[]> An array with the names of the supported cipher algorithms.

    const {
      getCiphers
    } = await import('node:crypto');

    console.log(getCiphers()); // ['aes-128-cbc', 'aes-128-ccm', ...]const {
      getCiphers,
    } = require('node:crypto');

    console.log(getCiphers()); // ['aes-128-cbc', 'aes-128-ccm', ...]

#### `crypto.getCurves()`#

Added in: v2.3.0

- Returns: <string[]> An array with the names of the supported elliptic curves.

    const {
      getCurves
    } = await import('node:crypto');

    console.log(getCurves()); // ['Oakley-EC2N-3', 'Oakley-EC2N-4', ...]const {
      getCurves,
    } = require('node:crypto');

    console.log(getCurves()); // ['Oakley-EC2N-3', 'Oakley-EC2N-4', ...]

#### `crypto.getDiffieHellman(groupName)`#

Added in: v0.7.5

- `groupName` <string>
- Returns: <DiffieHellmanGroup>

Creates a predefined `DiffieHellmanGroup` key exchange object. The supported groups are: `'modp1'`, `'modp2'`, `'modp5'` (defined in RFC 2412, but see Caveats) and `'modp14'`, `'modp15'`, `'modp16'`, `'modp17'`, `'modp18'` (defined in RFC 3526). The returned object mimics the interface of objects created by `crypto.createDiffieHellman()`, but will not allow changing the keys (with `diffieHellman.setPublicKey()`, for example). The advantage of using this method is that the parties do not have to generate nor exchange a group modulus beforehand, saving both processor and communication time.

Example (obtaining a shared secret):

    const {
      getDiffieHellman
    } = await import('node:crypto');
    const alice = getDiffieHellman('modp14');
    const bob = getDiffieHellman('modp14');

    alice.generateKeys();
    bob.generateKeys();

    const aliceSecret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
    const bobSecret = bob.computeSecret(alice.getPublicKey(), null, 'hex');

    /* aliceSecret and bobSecret should be the same */
    console.log(aliceSecret === bobSecret);const {
      getDiffieHellman,
    } = require('node:crypto');

    const alice = getDiffieHellman('modp14');
    const bob = getDiffieHellman('modp14');

    alice.generateKeys();
    bob.generateKeys();

    const aliceSecret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
    const bobSecret = bob.computeSecret(alice.getPublicKey(), null, 'hex');

    /* aliceSecret and bobSecret should be the same */
    console.log(aliceSecret === bobSecret);

#### `crypto.getFips()`#

Added in: v10.0.0

- Returns: <number> `1` if and only if a FIPS compliant crypto provider is currently in use, `0` otherwise. A future semver-major release may change the return type of this API to a <boolean>.

#### `crypto.getHashes()`#

Added in: v0.9.3

- Returns: <string[]> An array of the names of the supported hash algorithms, such as `'RSA-SHA256'`. Hash algorithms are also called "digest" algorithms.

    const {
      getHashes
    } = await import('node:crypto');

    console.log(getHashes()); // ['DSA', 'DSA-SHA', 'DSA-SHA1', ...]const {
      getHashes,
    } = require('node:crypto');

    console.log(getHashes()); // ['DSA', 'DSA-SHA', 'DSA-SHA1', ...]

#### `crypto.getRandomValues(typedArray)`#

Added in: v17.4.0

- `typedArray` <Buffer> | <TypedArray> | <DataView> | <ArrayBuffer>
- Returns: <Buffer> | <TypedArray> | <DataView> | <ArrayBuffer> Returns `typedArray`.

A convenient alias for `crypto.webcrypto.getRandomValues()`. This implementation is not compliant with the Web Crypto spec, to write web-compatible code use `crypto.webcrypto.getRandomValues()` instead.

#### `crypto.hkdf(digest, ikm, salt, info, keylen, callback)`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v15.0.0 | Added in: v15.0.0

- `digest` <string> The digest algorithm to use.
- `ikm` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> The input keying material. It must be at least one byte in length.
- `salt` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> The salt value. Must be provided but can be zero-length.
- `info` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> Additional info value. Must be provided but can be zero-length, and cannot be more than 1024 bytes.
- `keylen` <number> The length of the key to generate. Must be greater than 0. The maximum allowable value is `255` times the number of bytes produced by the selected digest function (e.g. `sha512` generates 64-byte hashes, making the maximum HKDF output 16320 bytes).
- `callback` <Function>
  - `err` <Error>
  - `derivedKey` <ArrayBuffer>

HKDF is a simple key derivation function defined in RFC 5869. The given `ikm`, `salt` and `info` are used with the `digest` to derive a key of `keylen` bytes.

The supplied `callback` function is called with two arguments: `err` and `derivedKey`. If an errors occurs while deriving the key, `err` will be set; otherwise `err` will be `null`. The successfully generated `derivedKey` will be passed to the callback as an <ArrayBuffer>. An error will be thrown if any of the input arguments specify invalid values or types.

    import { Buffer } from 'node:buffer';
    const {
      hkdf
    } = await import('node:crypto');

    hkdf('sha512', 'key', 'salt', 'info', 64, (err, derivedKey) => {
      if (err) throw err;
      console.log(Buffer.from(derivedKey).toString('hex'));  // '24156e2...5391653'
    });const {
      hkdf,
    } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    hkdf('sha512', 'key', 'salt', 'info', 64, (err, derivedKey) => {
      if (err) throw err;
      console.log(Buffer.from(derivedKey).toString('hex'));  // '24156e2...5391653'
    });

#### `crypto.hkdfSync(digest, ikm, salt, info, keylen)`#

Added in: v15.0.0

- `digest` <string> The digest algorithm to use.
- `ikm` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> The input keying material. It must be at least one byte in length.
- `salt` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> The salt value. Must be provided but can be zero-length.
- `info` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> Additional info value. Must be provided but can be zero-length, and cannot be more than 1024 bytes.
- `keylen` <number> The length of the key to generate. Must be greater than 0. The maximum allowable value is `255` times the number of bytes produced by the selected digest function (e.g. `sha512` generates 64-byte hashes, making the maximum HKDF output 16320 bytes).
- Returns: <ArrayBuffer>

Provides a synchronous HKDF key derivation function as defined in RFC 5869. The given `ikm`, `salt` and `info` are used with the `digest` to derive a key of `keylen` bytes.

The successfully generated `derivedKey` will be returned as an <ArrayBuffer>.

An error will be thrown if any of the input arguments specify invalid values or types, or if the derived key cannot be generated.

    import { Buffer } from 'node:buffer';
    const {
      hkdfSync
    } = await import('node:crypto');

    const derivedKey = hkdfSync('sha512', 'key', 'salt', 'info', 64);
    console.log(Buffer.from(derivedKey).toString('hex'));  // '24156e2...5391653'const {
      hkdfSync,
    } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    const derivedKey = hkdfSync('sha512', 'key', 'salt', 'info', 64);
    console.log(Buffer.from(derivedKey).toString('hex'));  // '24156e2...5391653'

#### `crypto.pbkdf2(password, salt, iterations, keylen, digest, callback)`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v15.0.0 | The password and salt arguments can also be ArrayBuffer instances.
v14.0.0 | The `iterations` parameter is now restricted to positive values. Earlier releases treated other values as one.
v8.0.0 | The `digest` parameter is always required now.
v6.0.0 | Calling this function without passing the `digest` parameter is deprecated now and will emit a warning.
v6.0.0 | The default encoding for `password` if it is a string changed from `binary` to `utf8`.
v0.5.5 | Added in: v0.5.5

- `password` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `salt` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `iterations` <number>
- `keylen` <number>
- `digest` <string>
- `callback` <Function>
  - `err` <Error>
  - `derivedKey` <Buffer>

Provides an asynchronous Password-Based Key Derivation Function 2 (PBKDF2) implementation. A selected HMAC digest algorithm specified by `digest` is applied to derive a key of the requested byte length (`keylen`) from the `password`, `salt` and `iterations`.

The supplied `callback` function is called with two arguments: `err` and `derivedKey`. If an error occurs while deriving the key, `err` will be set; otherwise `err` will be `null`. By default, the successfully generated `derivedKey` will be passed to the callback as a `Buffer`. An error will be thrown if any of the input arguments specify invalid values or types.

If `digest` is `null`, `'sha1'` will be used. This behavior is deprecated, please specify a `digest` explicitly.

The `iterations` argument must be a number set as high as possible. The higher the number of iterations, the more secure the derived key will be, but will take a longer amount of time to complete.

The `salt` should be as unique as possible. It is recommended that a salt is random and at least 16 bytes long. See NIST SP 800-132 for details.

When passing strings for `password` or `salt`, please consider caveats when using strings as inputs to cryptographic APIs.

    const {
      pbkdf2
    } = await import('node:crypto');

    pbkdf2('secret', 'salt', 100000, 64, 'sha512', (err, derivedKey) => {
      if (err) throw err;
      console.log(derivedKey.toString('hex'));  // '3745e48...08d59ae'
    });const {
      pbkdf2,
    } = require('node:crypto');

    pbkdf2('secret', 'salt', 100000, 64, 'sha512', (err, derivedKey) => {
      if (err) throw err;
      console.log(derivedKey.toString('hex'));  // '3745e48...08d59ae'
    });

The `crypto.DEFAULT_ENCODING` property can be used to change the way the `derivedKey` is passed to the callback. This property, however, has been deprecated and use should be avoided.

    import crypto from 'node:crypto';
    crypto.DEFAULT_ENCODING = 'hex';
    crypto.pbkdf2('secret', 'salt', 100000, 512, 'sha512', (err, derivedKey) => {
      if (err) throw err;
      console.log(derivedKey);  // '3745e48...aa39b34'
    });const crypto = require('node:crypto');
    crypto.DEFAULT_ENCODING = 'hex';
    crypto.pbkdf2('secret', 'salt', 100000, 512, 'sha512', (err, derivedKey) => {
      if (err) throw err;
      console.log(derivedKey);  // '3745e48...aa39b34'
    });

An array of supported digest functions can be retrieved using `crypto.getHashes()`.

This API uses libuv's threadpool, which can have surprising and negative performance implications for some applications; see the `UV_THREADPOOL_SIZE` documentation for more information.

#### `crypto.pbkdf2Sync(password, salt, iterations, keylen, digest)`#

History

Version | Changes
--- | ---
v14.0.0 | The `iterations` parameter is now restricted to positive values. Earlier releases treated other values as one.
v6.0.0 | Calling this function without passing the `digest` parameter is deprecated now and will emit a warning.
v6.0.0 | The default encoding for `password` if it is a string changed from `binary` to `utf8`.
v0.9.3 | Added in: v0.9.3

- `password` <string> | <Buffer> | <TypedArray> | <DataView>
- `salt` <string> | <Buffer> | <TypedArray> | <DataView>
- `iterations` <number>
- `keylen` <number>
- `digest` <string>
- Returns: <Buffer>

Provides a synchronous Password-Based Key Derivation Function 2 (PBKDF2) implementation. A selected HMAC digest algorithm specified by `digest` is applied to derive a key of the requested byte length (`keylen`) from the `password`, `salt` and `iterations`.

If an error occurs an `Error` will be thrown, otherwise the derived key will be returned as a `Buffer`.

If `digest` is `null`, `'sha1'` will be used. This behavior is deprecated, please specify a `digest` explicitly.

The `iterations` argument must be a number set as high as possible. The higher the number of iterations, the more secure the derived key will be, but will take a longer amount of time to complete.

The `salt` should be as unique as possible. It is recommended that a salt is random and at least 16 bytes long. See NIST SP 800-132 for details.

When passing strings for `password` or `salt`, please consider caveats when using strings as inputs to cryptographic APIs.

    const {
      pbkdf2Sync
    } = await import('node:crypto');

    const key = pbkdf2Sync('secret', 'salt', 100000, 64, 'sha512');
    console.log(key.toString('hex'));  // '3745e48...08d59ae'const {
      pbkdf2Sync,
    } = require('node:crypto');

    const key = pbkdf2Sync('secret', 'salt', 100000, 64, 'sha512');
    console.log(key.toString('hex'));  // '3745e48...08d59ae'

The `crypto.DEFAULT_ENCODING` property may be used to change the way the `derivedKey` is returned. This property, however, is deprecated and use should be avoided.

    import crypto from 'node:crypto';
    crypto.DEFAULT_ENCODING = 'hex';
    const key = crypto.pbkdf2Sync('secret', 'salt', 100000, 512, 'sha512');
    console.log(key);  // '3745e48...aa39b34'const crypto = require('node:crypto');
    crypto.DEFAULT_ENCODING = 'hex';
    const key = crypto.pbkdf2Sync('secret', 'salt', 100000, 512, 'sha512');
    console.log(key);  // '3745e48...aa39b34'

An array of supported digest functions can be retrieved using `crypto.getHashes()`.

#### `crypto.privateDecrypt(privateKey, buffer)`#

History

Version | Changes
--- | ---
v15.0.0 | Added string, ArrayBuffer, and CryptoKey as allowable key types. The oaepLabel can be an ArrayBuffer. The buffer can be a string or ArrayBuffer. All types that accept buffers are limited to a maximum of 2 ** 31 - 1 bytes.
v12.11.0 | The `oaepLabel` option was added.
v12.9.0 | The `oaepHash` option was added.
v11.6.0 | This function now supports key objects.
v0.11.14 | Added in: v0.11.14

- `privateKey` <Object> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
  - `oaepHash` <string> The hash function to use for OAEP padding and MGF1. Default: `'sha1'`
  - `oaepLabel` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> The label to use for OAEP padding. If not specified, no label is used.
  - `padding` <crypto.constants> An optional padding value defined in `crypto.constants`, which may be: `crypto.constants.RSA_NO_PADDING`, `crypto.constants.RSA_PKCS1_PADDING`, or `crypto.constants.RSA_PKCS1_OAEP_PADDING`.
- `buffer` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- Returns: <Buffer> A new `Buffer` with the decrypted content.

Decrypts `buffer` with `privateKey`. `buffer` was previously encrypted using the corresponding public key, for example using `crypto.publicEncrypt()`.

If `privateKey` is not a `KeyObject`, this function behaves as if `privateKey` had been passed to `crypto.createPrivateKey()`. If it is an object, the `padding` property can be passed. Otherwise, this function uses `RSA_PKCS1_OAEP_PADDING`.

#### `crypto.privateEncrypt(privateKey, buffer)`#

History

Version | Changes
--- | ---
v15.0.0 | Added string, ArrayBuffer, and CryptoKey as allowable key types. The passphrase can be an ArrayBuffer. The buffer can be a string or ArrayBuffer. All types that accept buffers are limited to a maximum of 2 ** 31 - 1 bytes.
v11.6.0 | This function now supports key objects.
v1.1.0 | Added in: v1.1.0

- `privateKey` <Object> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
  - `key` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey> A PEM encoded private key.
  - `passphrase` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> An optional passphrase for the private key.
  - `padding` <crypto.constants> An optional padding value defined in `crypto.constants`, which may be: `crypto.constants.RSA_NO_PADDING` or `crypto.constants.RSA_PKCS1_PADDING`.
  - `encoding` <string> The string encoding to use when `buffer`, `key`, or `passphrase` are strings.
- `buffer` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- Returns: <Buffer> A new `Buffer` with the encrypted content.

Encrypts `buffer` with `privateKey`. The returned data can be decrypted using the corresponding public key, for example using `crypto.publicDecrypt()`.

If `privateKey` is not a `KeyObject`, this function behaves as if `privateKey` had been passed to `crypto.createPrivateKey()`. If it is an object, the `padding` property can be passed. Otherwise, this function uses `RSA_PKCS1_PADDING`.

#### `crypto.publicDecrypt(key, buffer)`#

History

Version | Changes
--- | ---
v15.0.0 | Added string, ArrayBuffer, and CryptoKey as allowable key types. The passphrase can be an ArrayBuffer. The buffer can be a string or ArrayBuffer. All types that accept buffers are limited to a maximum of 2 ** 31 - 1 bytes.
v11.6.0 | This function now supports key objects.
v1.1.0 | Added in: v1.1.0

- `key` <Object> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
  - `passphrase` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> An optional passphrase for the private key.
  - `padding` <crypto.constants> An optional padding value defined in `crypto.constants`, which may be: `crypto.constants.RSA_NO_PADDING` or `crypto.constants.RSA_PKCS1_PADDING`.
  - `encoding` <string> The string encoding to use when `buffer`, `key`, or `passphrase` are strings.
- `buffer` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- Returns: <Buffer> A new `Buffer` with the decrypted content.

Decrypts `buffer` with `key`.`buffer` was previously encrypted using the corresponding private key, for example using `crypto.privateEncrypt()`.

If `key` is not a `KeyObject`, this function behaves as if `key` had been passed to `crypto.createPublicKey()`. If it is an object, the `padding` property can be passed. Otherwise, this function uses `RSA_PKCS1_PADDING`.

Because RSA public keys can be derived from private keys, a private key may be passed instead of a public key.

#### `crypto.publicEncrypt(key, buffer)`#

History

Version | Changes
--- | ---
v15.0.0 | Added string, ArrayBuffer, and CryptoKey as allowable key types. The oaepLabel and passphrase can be ArrayBuffers. The buffer can be a string or ArrayBuffer. All types that accept buffers are limited to a maximum of 2 ** 31 - 1 bytes.
v12.11.0 | The `oaepLabel` option was added.
v12.9.0 | The `oaepHash` option was added.
v11.6.0 | This function now supports key objects.
v0.11.14 | Added in: v0.11.14

- `key` <Object> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
  - `key` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey> A PEM encoded public or private key, <KeyObject>, or <CryptoKey>.
  - `oaepHash` <string> The hash function to use for OAEP padding and MGF1. Default: `'sha1'`
  - `oaepLabel` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> The label to use for OAEP padding. If not specified, no label is used.
  - `passphrase` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> An optional passphrase for the private key.
  - `padding` <crypto.constants> An optional padding value defined in `crypto.constants`, which may be: `crypto.constants.RSA_NO_PADDING`, `crypto.constants.RSA_PKCS1_PADDING`, or `crypto.constants.RSA_PKCS1_OAEP_PADDING`.
  - `encoding` <string> The string encoding to use when `buffer`, `key`, `oaepLabel`, or `passphrase` are strings.
- `buffer` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- Returns: <Buffer> A new `Buffer` with the encrypted content.

Encrypts the content of `buffer` with `key` and returns a new `Buffer` with encrypted content. The returned data can be decrypted using the corresponding private key, for example using `crypto.privateDecrypt()`.

If `key` is not a `KeyObject`, this function behaves as if `key` had been passed to `crypto.createPublicKey()`. If it is an object, the `padding` property can be passed. Otherwise, this function uses `RSA_PKCS1_OAEP_PADDING`.

Because RSA public keys can be derived from private keys, a private key may be passed instead of a public key.

#### `crypto.randomBytes(size[, callback])`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v9.0.0 | Passing `null` as the `callback` argument now throws `ERR_INVALID_CALLBACK`.
v0.5.8 | Added in: v0.5.8

- `size` <number> The number of bytes to generate. The `size` must not be larger than `2**31 - 1`.
- `callback` <Function>
  - `err` <Error>
  - `buf` <Buffer>
- Returns: <Buffer> if the `callback` function is not provided.

Generates cryptographically strong pseudorandom data. The `size` argument is a number indicating the number of bytes to generate.

If a `callback` function is provided, the bytes are generated asynchronously and the `callback` function is invoked with two arguments: `err` and `buf`. If an error occurs, `err` will be an `Error` object; otherwise it is `null`. The `buf` argument is a `Buffer` containing the generated bytes.

    // Asynchronous
    const {
      randomBytes
    } = await import('node:crypto');

    randomBytes(256, (err, buf) => {
      if (err) throw err;
      console.log(`${buf.length} bytes of random data: ${buf.toString('hex')}`);
    });// Asynchronous
    const {
      randomBytes,
    } = require('node:crypto');

    randomBytes(256, (err, buf) => {
      if (err) throw err;
      console.log(`${buf.length} bytes of random data: ${buf.toString('hex')}`);
    });

If the `callback` function is not provided, the random bytes are generated synchronously and returned as a `Buffer`. An error will be thrown if there is a problem generating the bytes.

    // Synchronous
    const {
      randomBytes
    } = await import('node:crypto');

    const buf = randomBytes(256);
    console.log(
      `${buf.length} bytes of random data: ${buf.toString('hex')}`);// Synchronous
    const {
      randomBytes,
    } = require('node:crypto');

    const buf = randomBytes(256);
    console.log(
      `${buf.length} bytes of random data: ${buf.toString('hex')}`);

The `crypto.randomBytes()` method will not complete until there is sufficient entropy available. This should normally never take longer than a few milliseconds. The only time when generating the random bytes may conceivably block for a longer period of time is right after boot, when the whole system is still low on entropy.

This API uses libuv's threadpool, which can have surprising and negative performance implications for some applications; see the `UV_THREADPOOL_SIZE` documentation for more information.

The asynchronous version of `crypto.randomBytes()` is carried out in a single threadpool request. To minimize threadpool task length variation, partition large `randomBytes` requests when doing so as part of fulfilling a client request.

#### `crypto.randomFillSync(buffer[, offset][, size])`#

History

Version | Changes
--- | ---
v9.0.0 | The `buffer` argument may be any `TypedArray` or `DataView`.
v7.10.0, v6.13.0 | Added in: v7.10.0, v6.13.0

- `buffer` <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> Must be supplied. The size of the provided `buffer` must not be larger than `2**31 - 1`.
- `offset` <number> Default: `0`
- `size` <number> Default: `buffer.length - offset`. The `size` must not be larger than `2**31 - 1`.
- Returns: <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> The object passed as `buffer` argument.

Synchronous version of `crypto.randomFill()`.

    import { Buffer } from 'node:buffer';
    const { randomFillSync } = await import('node:crypto');

    const buf = Buffer.alloc(10);
    console.log(randomFillSync(buf).toString('hex'));

    randomFillSync(buf, 5);
    console.log(buf.toString('hex'));

    // The above is equivalent to the following:
    randomFillSync(buf, 5, 5);
    console.log(buf.toString('hex'));const { randomFillSync } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    const buf = Buffer.alloc(10);
    console.log(randomFillSync(buf).toString('hex'));

    randomFillSync(buf, 5);
    console.log(buf.toString('hex'));

    // The above is equivalent to the following:
    randomFillSync(buf, 5, 5);
    console.log(buf.toString('hex'));

Any `ArrayBuffer`, `TypedArray` or `DataView` instance may be passed as `buffer`.

    import { Buffer } from 'node:buffer';
    const { randomFillSync } = await import('node:crypto');

    const a = new Uint32Array(10);
    console.log(Buffer.from(randomFillSync(a).buffer,
                            a.byteOffset, a.byteLength).toString('hex'));

    const b = new DataView(new ArrayBuffer(10));
    console.log(Buffer.from(randomFillSync(b).buffer,
                            b.byteOffset, b.byteLength).toString('hex'));

    const c = new ArrayBuffer(10);
    console.log(Buffer.from(randomFillSync(c)).toString('hex'));const { randomFillSync } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    const a = new Uint32Array(10);
    console.log(Buffer.from(randomFillSync(a).buffer,
                            a.byteOffset, a.byteLength).toString('hex'));

    const b = new DataView(new ArrayBuffer(10));
    console.log(Buffer.from(randomFillSync(b).buffer,
                            b.byteOffset, b.byteLength).toString('hex'));

    const c = new ArrayBuffer(10);
    console.log(Buffer.from(randomFillSync(c)).toString('hex'));

#### `crypto.randomFill(buffer[, offset][, size], callback)`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v9.0.0 | The `buffer` argument may be any `TypedArray` or `DataView`.
v7.10.0, v6.13.0 | Added in: v7.10.0, v6.13.0

- `buffer` <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> Must be supplied. The size of the provided `buffer` must not be larger than `2**31 - 1`.
- `offset` <number> Default: `0`
- `size` <number> Default: `buffer.length - offset`. The `size` must not be larger than `2**31 - 1`.
- `callback` <Function> `function(err, buf) {}`.

This function is similar to `crypto.randomBytes()` but requires the first argument to be a `Buffer` that will be filled. It also requires that a callback is passed in.

If the `callback` function is not provided, an error will be thrown.

    import { Buffer } from 'node:buffer';
    const { randomFill } = await import('node:crypto');

    const buf = Buffer.alloc(10);
    randomFill(buf, (err, buf) => {
      if (err) throw err;
      console.log(buf.toString('hex'));
    });

    randomFill(buf, 5, (err, buf) => {
      if (err) throw err;
      console.log(buf.toString('hex'));
    });

    // The above is equivalent to the following:
    randomFill(buf, 5, 5, (err, buf) => {
      if (err) throw err;
      console.log(buf.toString('hex'));
    });const { randomFill } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    const buf = Buffer.alloc(10);
    randomFill(buf, (err, buf) => {
      if (err) throw err;
      console.log(buf.toString('hex'));
    });

    randomFill(buf, 5, (err, buf) => {
      if (err) throw err;
      console.log(buf.toString('hex'));
    });

    // The above is equivalent to the following:
    randomFill(buf, 5, 5, (err, buf) => {
      if (err) throw err;
      console.log(buf.toString('hex'));
    });

Any `ArrayBuffer`, `TypedArray`, or `DataView` instance may be passed as `buffer`.

While this includes instances of `Float32Array` and `Float64Array`, this function should not be used to generate random floating-point numbers. The result may contain `+Infinity`, `-Infinity`, and `NaN`, and even if the array contains finite numbers only, they are not drawn from a uniform random distribution and have no meaningful lower or upper bounds.

    import { Buffer } from 'node:buffer';
    const { randomFill } = await import('node:crypto');

    const a = new Uint32Array(10);
    randomFill(a, (err, buf) => {
      if (err) throw err;
      console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
        .toString('hex'));
    });

    const b = new DataView(new ArrayBuffer(10));
    randomFill(b, (err, buf) => {
      if (err) throw err;
      console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
        .toString('hex'));
    });

    const c = new ArrayBuffer(10);
    randomFill(c, (err, buf) => {
      if (err) throw err;
      console.log(Buffer.from(buf).toString('hex'));
    });const { randomFill } = require('node:crypto');
    const { Buffer } = require('node:buffer');

    const a = new Uint32Array(10);
    randomFill(a, (err, buf) => {
      if (err) throw err;
      console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
        .toString('hex'));
    });

    const b = new DataView(new ArrayBuffer(10));
    randomFill(b, (err, buf) => {
      if (err) throw err;
      console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
        .toString('hex'));
    });

    const c = new ArrayBuffer(10);
    randomFill(c, (err, buf) => {
      if (err) throw err;
      console.log(Buffer.from(buf).toString('hex'));
    });

This API uses libuv's threadpool, which can have surprising and negative performance implications for some applications; see the `UV_THREADPOOL_SIZE` documentation for more information.

The asynchronous version of `crypto.randomFill()` is carried out in a single threadpool request. To minimize threadpool task length variation, partition large `randomFill` requests when doing so as part of fulfilling a client request.

#### `crypto.randomInt([min, ]max[, callback])`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v14.10.0, v12.19.0 | Added in: v14.10.0, v12.19.0

- `min` <integer> Start of random range (inclusive). Default: `0`.
- `max` <integer> End of random range (exclusive).
- `callback` <Function> `function(err, n) {}`.

Return a random integer `n` such that `min <= n < max`. This implementation avoids modulo bias.

The range (`max - min`) must be less than 248. `min` and `max` must be safe integers.

If the `callback` function is not provided, the random integer is generated synchronously.

    // Asynchronous
    const {
      randomInt
    } = await import('node:crypto');

    randomInt(3, (err, n) => {
      if (err) throw err;
      console.log(`Random number chosen from (0, 1, 2): ${n}`);
    });// Asynchronous
    const {
      randomInt,
    } = require('node:crypto');

    randomInt(3, (err, n) => {
      if (err) throw err;
      console.log(`Random number chosen from (0, 1, 2): ${n}`);
    });

    // Synchronous
    const {
      randomInt
    } = await import('node:crypto');

    const n = randomInt(3);
    console.log(`Random number chosen from (0, 1, 2): ${n}`);// Synchronous
    const {
      randomInt,
    } = require('node:crypto');

    const n = randomInt(3);
    console.log(`Random number chosen from (0, 1, 2): ${n}`);

    // With `min` argument
    const {
      randomInt
    } = await import('node:crypto');

    const n = randomInt(1, 7);
    console.log(`The dice rolled: ${n}`);// With `min` argument
    const {
      randomInt,
    } = require('node:crypto');

    const n = randomInt(1, 7);
    console.log(`The dice rolled: ${n}`);

#### `crypto.randomUUID([options])`#

Added in: v15.6.0, v14.17.0

- `options` <Object>
  - `disableEntropyCache` <boolean> By default, to improve performance, Node.js generates and caches enough random data to generate up to 128 random UUIDs. To generate a UUID without using the cache, set `disableEntropyCache` to `true`. Default: `false`.
- Returns: <string>

Generates a random RFC 4122 version 4 UUID. The UUID is generated using a cryptographic pseudorandom number generator.

#### `crypto.scrypt(password, salt, keylen[, options], callback)`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v15.0.0 | The password and salt arguments can also be ArrayBuffer instances.
v12.8.0, v10.17.0 | The `maxmem` value can now be any safe integer.
v10.9.0 | The `cost`, `blockSize` and `parallelization` option names have been added.
v10.5.0 | Added in: v10.5.0

- `password` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `salt` <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `keylen` <number>
- `options` <Object>
  - `cost` <number> CPU/memory cost parameter. Must be a power of two greater than one. Default: `16384`.
  - `blockSize` <number> Block size parameter. Default: `8`.
  - `parallelization` <number> Parallelization parameter. Default: `1`.
  - `N` <number> Alias for `cost`. Only one of both may be specified.
  - `r` <number> Alias for `blockSize`. Only one of both may be specified.
  - `p` <number> Alias for `parallelization`. Only one of both may be specified.
  - `maxmem` <number> Memory upper bound. It is an error when (approximately) `128 * N * r > maxmem`. Default: `32 * 1024 * 1024`.
- `callback` <Function>
  - `err` <Error>
  - `derivedKey` <Buffer>

Provides an asynchronous scrypt implementation. Scrypt is a password-based key derivation function that is designed to be expensive computationally and memory-wise in order to make brute-force attacks unrewarding.

The `salt` should be as unique as possible. It is recommended that a salt is random and at least 16 bytes long. See NIST SP 800-132 for details.

When passing strings for `password` or `salt`, please consider caveats when using strings as inputs to cryptographic APIs.

The `callback` function is called with two arguments: `err` and `derivedKey`. `err` is an exception object when key derivation fails, otherwise `err` is `null`. `derivedKey` is passed to the callback as a `Buffer`.

An exception is thrown when any of the input arguments specify invalid values or types.

    const {
      scrypt
    } = await import('node:crypto');

    // Using the factory defaults.
    scrypt('password', 'salt', 64, (err, derivedKey) => {
      if (err) throw err;
      console.log(derivedKey.toString('hex'));  // '3745e48...08d59ae'
    });
    // Using a custom N parameter. Must be a power of two.
    scrypt('password', 'salt', 64, { N: 1024 }, (err, derivedKey) => {
      if (err) throw err;
      console.log(derivedKey.toString('hex'));  // '3745e48...aa39b34'
    });const {
      scrypt,
    } = require('node:crypto');

    // Using the factory defaults.
    scrypt('password', 'salt', 64, (err, derivedKey) => {
      if (err) throw err;
      console.log(derivedKey.toString('hex'));  // '3745e48...08d59ae'
    });
    // Using a custom N parameter. Must be a power of two.
    scrypt('password', 'salt', 64, { N: 1024 }, (err, derivedKey) => {
      if (err) throw err;
      console.log(derivedKey.toString('hex'));  // '3745e48...aa39b34'
    });

#### `crypto.scryptSync(password, salt, keylen[, options])`#

History

Version | Changes
--- | ---
v12.8.0, v10.17.0 | The `maxmem` value can now be any safe integer.
v10.9.0 | The `cost`, `blockSize` and `parallelization` option names have been added.
v10.5.0 | Added in: v10.5.0

- `password` <string> | <Buffer> | <TypedArray> | <DataView>
- `salt` <string> | <Buffer> | <TypedArray> | <DataView>
- `keylen` <number>
- `options` <Object>
  - `cost` <number> CPU/memory cost parameter. Must be a power of two greater than one. Default: `16384`.
  - `blockSize` <number> Block size parameter. Default: `8`.
  - `parallelization` <number> Parallelization parameter. Default: `1`.
  - `N` <number> Alias for `cost`. Only one of both may be specified.
  - `r` <number> Alias for `blockSize`. Only one of both may be specified.
  - `p` <number> Alias for `parallelization`. Only one of both may be specified.
  - `maxmem` <number> Memory upper bound. It is an error when (approximately) `128 * N * r > maxmem`. Default: `32 * 1024 * 1024`.
- Returns: <Buffer>

Provides a synchronous scrypt implementation. Scrypt is a password-based key derivation function that is designed to be expensive computationally and memory-wise in order to make brute-force attacks unrewarding.

The `salt` should be as unique as possible. It is recommended that a salt is random and at least 16 bytes long. See NIST SP 800-132 for details.

When passing strings for `password` or `salt`, please consider caveats when using strings as inputs to cryptographic APIs.

An exception is thrown when key derivation fails, otherwise the derived key is returned as a `Buffer`.

An exception is thrown when any of the input arguments specify invalid values or types.

    const {
      scryptSync
    } = await import('node:crypto');
    // Using the factory defaults.

    const key1 = scryptSync('password', 'salt', 64);
    console.log(key1.toString('hex'));  // '3745e48...08d59ae'
    // Using a custom N parameter. Must be a power of two.
    const key2 = scryptSync('password', 'salt', 64, { N: 1024 });
    console.log(key2.toString('hex'));  // '3745e48...aa39b34'const {
      scryptSync,
    } = require('node:crypto');
    // Using the factory defaults.

    const key1 = scryptSync('password', 'salt', 64);
    console.log(key1.toString('hex'));  // '3745e48...08d59ae'
    // Using a custom N parameter. Must be a power of two.
    const key2 = scryptSync('password', 'salt', 64, { N: 1024 });
    console.log(key2.toString('hex'));  // '3745e48...aa39b34'

#### `crypto.secureHeapUsed()`#

Added in: v15.6.0

- Returns: <Object>
  - `total` <number> The total allocated secure heap size as specified using the `--secure-heap=n` command-line flag.
  - `min` <number> The minimum allocation from the secure heap as specified using the `--secure-heap-min` command-line flag.
  - `used` <number> The total number of bytes currently allocated from the secure heap.
  - `utilization` <number> The calculated ratio of `used` to `total` allocated bytes.

#### `crypto.setEngine(engine[, flags])`#

Added in: v0.11.11

- `engine` <string>
- `flags` <crypto.constants> Default: `crypto.constants.ENGINE_METHOD_ALL`

Load and set the `engine` for some or all OpenSSL functions (selected by flags).

`engine` could be either an id or a path to the engine's shared library.

The optional `flags` argument uses `ENGINE_METHOD_ALL` by default. The `flags` is a bit field taking one of or a mix of the following flags (defined in `crypto.constants`):

- `crypto.constants.ENGINE_METHOD_RSA`
- `crypto.constants.ENGINE_METHOD_DSA`
- `crypto.constants.ENGINE_METHOD_DH`
- `crypto.constants.ENGINE_METHOD_RAND`
- `crypto.constants.ENGINE_METHOD_EC`
- `crypto.constants.ENGINE_METHOD_CIPHERS`
- `crypto.constants.ENGINE_METHOD_DIGESTS`
- `crypto.constants.ENGINE_METHOD_PKEY_METHS`
- `crypto.constants.ENGINE_METHOD_PKEY_ASN1_METHS`
- `crypto.constants.ENGINE_METHOD_ALL`
- `crypto.constants.ENGINE_METHOD_NONE`

The flags below are deprecated in OpenSSL-1.1.0.

- `crypto.constants.ENGINE_METHOD_ECDH`
- `crypto.constants.ENGINE_METHOD_ECDSA`
- `crypto.constants.ENGINE_METHOD_STORE`

#### `crypto.setFips(bool)`#

Added in: v10.0.0

- `bool` <boolean> `true` to enable FIPS mode.

Enables the FIPS compliant crypto provider in a FIPS-enabled Node.js build. Throws an error if FIPS mode is not available.

#### `crypto.sign(algorithm, data, key[, callback])`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v15.12.0 | Optional callback argument added.
v13.2.0, v12.16.0 | This function now supports IEEE-P1363 DSA and ECDSA signatures.
v12.0.0 | Added in: v12.0.0

- `algorithm` <string> | <null> | <undefined>
- `data` <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `key` <Object> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
- `callback` <Function>
  - `err` <Error>
  - `signature` <Buffer>
- Returns: <Buffer> if the `callback` function is not provided.

Calculates and returns the signature for `data` using the given private key and algorithm. If `algorithm` is `null` or `undefined`, then the algorithm is dependent upon the key type (especially Ed25519 and Ed448).

If `key` is not a `KeyObject`, this function behaves as if `key` had been passed to `crypto.createPrivateKey()`. If it is an object, the following additional properties can be passed:

- `dsaEncoding` <string> For DSA and ECDSA, this option specifies the format of the generated signature. It can be one of the following:

  - `'der'` (default): DER-encoded ASN.1 signature structure encoding `(r, s)`.
  - `'ieee-p1363'`: Signature format `r || s` as proposed in IEEE-P1363.

- `padding` <integer> Optional padding value for RSA, one of the following:

  - `crypto.constants.RSA_PKCS1_PADDING` (default)
  - `crypto.constants.RSA_PKCS1_PSS_PADDING`

  `RSA_PKCS1_PSS_PADDING` will use MGF1 with the same hash function used to sign the message as specified in section 3.1 of RFC 4055.

- `saltLength` <integer> Salt length for when padding is `RSA_PKCS1_PSS_PADDING`. The special value `crypto.constants.RSA_PSS_SALTLEN_DIGEST` sets the salt length to the digest size, `crypto.constants.RSA_PSS_SALTLEN_MAX_SIGN` (default) sets it to the maximum permissible value.

If the `callback` function is provided this function uses libuv's threadpool.

#### `crypto.subtle`#

Added in: v17.4.0

- Type: <SubtleCrypto>

A convenient alias for `crypto.webcrypto.subtle`.

#### `crypto.timingSafeEqual(a, b)`#

History

Version | Changes
--- | ---
v15.0.0 | The a and b arguments can also be ArrayBuffer.
v6.6.0 | Added in: v6.6.0

- `a` <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `b` <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- Returns: <boolean>

This function is based on a constant-time algorithm. Returns true if `a` is equal to `b`, without leaking timing information that would allow an attacker to guess one of the values. This is suitable for comparing HMAC digests or secret values like authentication cookies or capability urls.

`a` and `b` must both be `Buffer`s, `TypedArray`s, or `DataView`s, and they must have the same byte length. An error is thrown if `a` and `b` have different byte lengths.

If at least one of `a` and `b` is a `TypedArray` with more than one byte per entry, such as `Uint16Array`, the result will be computed using the platform byte order.

Use of `crypto.timingSafeEqual` does not guarantee that the surrounding code is timing-safe. Care should be taken to ensure that the surrounding code does not introduce timing vulnerabilities.

#### `crypto.verify(algorithm, data, key, signature[, callback])`#

History

Version | Changes
--- | ---
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`.
v15.12.0 | Optional callback argument added.
v15.0.0 | The data, key, and signature arguments can also be ArrayBuffer.
v13.2.0, v12.16.0 | This function now supports IEEE-P1363 DSA and ECDSA signatures.
v12.0.0 | Added in: v12.0.0

- `algorithm` <string> | <null> | <undefined>
- `data` <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `key` <Object> | <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView> | <KeyObject> | <CryptoKey>
- `signature` <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>
- `callback` <Function>
  - `err` <Error>
  - `result` <boolean>
- Returns: <boolean> `true` or `false` depending on the validity of the signature for the data and public key if the `callback` function is not provided.

Verifies the given signature for `data` using the given key and algorithm. If `algorithm` is `null` or `undefined`, then the algorithm is dependent upon the key type (especially Ed25519 and Ed448).

If `key` is not a `KeyObject`, this function behaves as if `key` had been passed to `crypto.createPublicKey()`. If it is an object, the following additional properties can be passed:

- `dsaEncoding` <string> For DSA and ECDSA, this option specifies the format of the signature. It can be one of the following:

  - `'der'` (default): DER-encoded ASN.1 signature structure encoding `(r, s)`.
  - `'ieee-p1363'`: Signature format `r || s` as proposed in IEEE-P1363.

- `padding` <integer> Optional padding value for RSA, one of the following:

  - `crypto.constants.RSA_PKCS1_PADDING` (default)
  - `crypto.constants.RSA_PKCS1_PSS_PADDING`

  `RSA_PKCS1_PSS_PADDING` will use MGF1 with the same hash function used to sign the message as specified in section 3.1 of RFC 4055.

- `saltLength` <integer> Salt length for when padding is `RSA_PKCS1_PSS_PADDING`. The special value `crypto.constants.RSA_PSS_SALTLEN_DIGEST` sets the salt length to the digest size, `crypto.constants.RSA_PSS_SALTLEN_MAX_SIGN` (default) sets it to the maximum permissible value.

The `signature` argument is the previously calculated signature for the `data`.

Because public keys can be derived from private keys, a private key or a public key may be passed for `key`.

If the `callback` function is provided this function uses libuv's threadpool.

#### `crypto.webcrypto`#

Added in: v15.0.0

Type: <Crypto> An implementation of the Web Crypto API standard.

See the Web Crypto API documentation for details.

### Notes#

#### Using strings as inputs to cryptographic APIs#

For historical reasons, many cryptographic APIs provided by Node.js accept strings as inputs where the underlying cryptographic algorithm works on byte sequences. These instances include plaintexts, ciphertexts, symmetric keys, initialization vectors, passphrases, salts, authentication tags, and additional authenticated data.

When passing strings to cryptographic APIs, consider the following factors.

- Not all byte sequences are valid UTF-8 strings. Therefore, when a byte sequence of length `n` is derived from a string, its entropy is generally lower than the entropy of a random or pseudorandom `n` byte sequence. For example, no UTF-8 string will result in the byte sequence `c0 af`. Secret keys should almost exclusively be random or pseudorandom byte sequences.

- Similarly, when converting random or pseudorandom byte sequences to UTF-8 strings, subsequences that do not represent valid code points may be replaced by the Unicode replacement character (`U+FFFD`). The byte representation of the resulting Unicode string may, therefore, not be equal to the byte sequence that the string was created from.

      const original = [0xc0, 0xaf];
      const bytesAsString = Buffer.from(original).toString('utf8');
      const stringAsBytes = Buffer.from(bytesAsString, 'utf8');
      console.log(stringAsBytes);
      // Prints '<Buffer ef bf bd ef bf bd>'.

  The outputs of ciphers, hash functions, signature algorithms, and key derivation functions are pseudorandom byte sequences and should not be used as Unicode strings.

- When strings are obtained from user input, some Unicode characters can be represented in multiple equivalent ways that result in different byte sequences. For example, when passing a user passphrase to a key derivation function, such as PBKDF2 or scrypt, the result of the key derivation function depends on whether the string uses composed or decomposed characters. Node.js does not normalize character representations. Developers should consider using `String.prototype.normalize()` on user inputs before passing them to cryptographic APIs.

#### Legacy streams API (prior to Node.js 0.10)#

The Crypto module was added to Node.js before there was the concept of a unified Stream API, and before there were `Buffer` objects for handling binary data. As such, the many of the `crypto` defined classes have methods not typically found on other Node.js classes that implement the streams API (e.g. `update()`, `final()`, or `digest()`). Also, many methods accepted and returned `'latin1'` encoded strings by default rather than `Buffer`s. This default was changed after Node.js v0.8 to use `Buffer` objects by default instead.

#### Support for weak or compromised algorithms#

The `node:crypto` module still supports some algorithms which are already compromised and are not currently recommended for use. The API also allows the use of ciphers and hashes with a small key size that are too weak for safe use.

Users should take full responsibility for selecting the crypto algorithm and key size according to their security requirements.

Based on the recommendations of NIST SP 800-131A:

- MD5 and SHA-1 are no longer acceptable where collision resistance is required such as digital signatures.
- The key used with RSA, DSA, and DH algorithms is recommended to have at least 2048 bits and that of the curve of ECDSA and ECDH at least 224 bits, to be safe to use for several years.
- The DH groups of `modp1`, `modp2` and `modp5` have a key size smaller than 2048 bits and are not recommended.

See the reference for other recommendations and details.

Some algorithms that have known weaknesses and are of little relevance in practice are only available through the legacy provider, which is not enabled by default.

#### CCM mode#

CCM is one of the supported AEAD algorithms. Applications which use this mode must adhere to certain restrictions when using the cipher API:

- The authentication tag length must be specified during cipher creation by setting the `authTagLength` option and must be one of 4, 6, 8, 10, 12, 14 or 16 bytes.
- The length of the initialization vector (nonce) `N` must be between 7 and 13 bytes (`7 ≤ N ≤ 13`).
- The length of the plaintext is limited to `2 ** (8 * (15 - N))` bytes.
- When decrypting, the authentication tag must be set via `setAuthTag()` before calling `update()`. Otherwise, decryption will fail and `final()` will throw an error in compliance with section 2.6 of RFC 3610.
- Using stream methods such as `write(data)`, `end(data)` or `pipe()` in CCM mode might fail as CCM cannot handle more than one chunk of data per instance.
- When passing additional authenticated data (AAD), the length of the actual message in bytes must be passed to `setAAD()` via the `plaintextLength` option. Many crypto libraries include the authentication tag in the ciphertext, which means that they produce ciphertexts of the length `plaintextLength + authTagLength`. Node.js does not include the authentication tag, so the ciphertext length is always `plaintextLength`. This is not necessary if no AAD is used.
- As CCM processes the whole message at once, `update()` must be called exactly once.
- Even though calling `update()` is sufficient to encrypt/decrypt the message, applications must call `final()` to compute or verify the authentication tag.

    import { Buffer } from 'node:buffer';
    const {
      createCipheriv,
      createDecipheriv,
      randomBytes
    } = await import('node:crypto');

    const key = 'keykeykeykeykeykeykeykey';
    const nonce = randomBytes(12);

    const aad = Buffer.from('0123456789', 'hex');

    const cipher = createCipheriv('aes-192-ccm', key, nonce, {
      authTagLength: 16
    });
    const plaintext = 'Hello world';
    cipher.setAAD(aad, {
      plaintextLength: Buffer.byteLength(plaintext)
    });
    const ciphertext = cipher.update(plaintext, 'utf8');
    cipher.final();
    const tag = cipher.getAuthTag();

    // Now transmit { ciphertext, nonce, tag }.

    const decipher = createDecipheriv('aes-192-ccm', key, nonce, {
      authTagLength: 16
    });
    decipher.setAuthTag(tag);
    decipher.setAAD(aad, {
      plaintextLength: ciphertext.length
    });
    const receivedPlaintext = decipher.update(ciphertext, null, 'utf8');

    try {
      decipher.final();
    } catch (err) {
      throw new Error('Authentication failed!', { cause: err });
    }

    console.log(receivedPlaintext);const { Buffer } = require('node:buffer');
    const {
      createCipheriv,
      createDecipheriv,
      randomBytes,
    } = require('node:crypto');

    const key = 'keykeykeykeykeykeykeykey';
    const nonce = randomBytes(12);

    const aad = Buffer.from('0123456789', 'hex');

    const cipher = createCipheriv('aes-192-ccm', key, nonce, {
      authTagLength: 16
    });
    const plaintext = 'Hello world';
    cipher.setAAD(aad, {
      plaintextLength: Buffer.byteLength(plaintext)
    });
    const ciphertext = cipher.update(plaintext, 'utf8');
    cipher.final();
    const tag = cipher.getAuthTag();

    // Now transmit { ciphertext, nonce, tag }.

    const decipher = createDecipheriv('aes-192-ccm', key, nonce, {
      authTagLength: 16
    });
    decipher.setAuthTag(tag);
    decipher.setAAD(aad, {
      plaintextLength: ciphertext.length
    });
    const receivedPlaintext = decipher.update(ciphertext, null, 'utf8');

    try {
      decipher.final();
    } catch (err) {
      throw new Error('Authentication failed!', { cause: err });
    }

    console.log(receivedPlaintext);

### Crypto constants#

The following constants exported by `crypto.constants` apply to various uses of the `node:crypto`, `node:tls`, and `node:https` modules and are generally specific to OpenSSL.

#### OpenSSL options#

See the list of SSL OP Flags for details.

Constant | Description
--- | ---
`SSL_OP_ALL` | Applies multiple bug workarounds within OpenSSL. See https://www.openssl.org/docs/man1.0.2/ssl/SSL_CTX_set_options.html for detail.
`SSL_OP_ALLOW_NO_DHE_KEX` | Instructs OpenSSL to allow a non-[EC]DHE-based key exchange mode for TLS v1.3
`SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION` | Allows legacy insecure renegotiation between OpenSSL and unpatched clients or servers. See https://www.openssl.org/docs/man1.0.2/ssl/SSL_CTX_set_options.html.
`SSL_OP_CIPHER_SERVER_PREFERENCE` | Attempts to use the server's preferences instead of the client's when selecting a cipher. Behavior depends on protocol version. See https://www.openssl.org/docs/man1.0.2/ssl/SSL_CTX_set_options.html.
`SSL_OP_CISCO_ANYCONNECT` | Instructs OpenSSL to use Cisco's "speshul" version of DTLS_BAD_VER.
`SSL_OP_COOKIE_EXCHANGE` | Instructs OpenSSL to turn on cookie exchange.
`SSL_OP_CRYPTOPRO_TLSEXT_BUG` | Instructs OpenSSL to add server-hello extension from an early version of the cryptopro draft.
`SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS` | Instructs OpenSSL to disable a SSL 3.0/TLS 1.0 vulnerability workaround added in OpenSSL 0.9.6d.
`SSL_OP_EPHEMERAL_RSA` | Instructs OpenSSL to always use the tmp_rsa key when performing RSA operations.
`SSL_OP_LEGACY_SERVER_CONNECT` | Allows initial connection to servers that do not support RI.
`SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER` |
`SSL_OP_MICROSOFT_SESS_ID_BUG` |
`SSL_OP_MSIE_SSLV2_RSA_PADDING` | Instructs OpenSSL to disable the workaround for a man-in-the-middle protocol-version vulnerability in the SSL 2.0 server implementation.
`SSL_OP_NETSCAPE_CA_DN_BUG` |
`SSL_OP_NETSCAPE_CHALLENGE_BUG` |
`SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG` |
`SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG` |
`SSL_OP_NO_COMPRESSION` | Instructs OpenSSL to disable support for SSL/TLS compression.
`SSL_OP_NO_ENCRYPT_THEN_MAC` | Instructs OpenSSL to disable encrypt-then-MAC.
`SSL_OP_NO_QUERY_MTU` |
`SSL_OP_NO_RENEGOTIATION` | Instructs OpenSSL to disable renegotiation.
`SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION` | Instructs OpenSSL to always start a new session when performing renegotiation.
`SSL_OP_NO_SSLv2` | Instructs OpenSSL to turn off SSL v2
`SSL_OP_NO_SSLv3` | Instructs OpenSSL to turn off SSL v3
`SSL_OP_NO_TICKET` | Instructs OpenSSL to disable use of RFC4507bis tickets.
`SSL_OP_NO_TLSv1` | Instructs OpenSSL to turn off TLS v1
`SSL_OP_NO_TLSv1_1` | Instructs OpenSSL to turn off TLS v1.1
`SSL_OP_NO_TLSv1_2` | Instructs OpenSSL to turn off TLS v1.2
`SSL_OP_NO_TLSv1_3` | Instructs OpenSSL to turn off TLS v1.3
`SSL_OP_PKCS1_CHECK_1` |
`SSL_OP_PKCS1_CHECK_2` |
`SSL_OP_PRIORITIZE_CHACHA` | Instructs OpenSSL server to prioritize ChaCha20-Poly1305 when the client does. This option has no effect if `SSL_OP_CIPHER_SERVER_PREFERENCE` is not enabled.
`SSL_OP_SINGLE_DH_USE` | Instructs OpenSSL to always create a new key when using temporary/ephemeral DH parameters.
`SSL_OP_SINGLE_ECDH_USE` | Instructs OpenSSL to always create a new key when using temporary/ephemeral ECDH parameters.
`SSL_OP_SSLEAY_080_CLIENT_DH_BUG` |
`SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG` |
`SSL_OP_TLS_BLOCK_PADDING_BUG` |
`SSL_OP_TLS_D5_BUG` |
`SSL_OP_TLS_ROLLBACK_BUG` | Instructs OpenSSL to disable version rollback attack detection.

#### OpenSSL engine constants#

Constant | Description
--- | ---
`ENGINE_METHOD_RSA` | Limit engine usage to RSA
`ENGINE_METHOD_DSA` | Limit engine usage to DSA
`ENGINE_METHOD_DH` | Limit engine usage to DH
`ENGINE_METHOD_RAND` | Limit engine usage to RAND
`ENGINE_METHOD_EC` | Limit engine usage to EC
`ENGINE_METHOD_CIPHERS` | Limit engine usage to CIPHERS
`ENGINE_METHOD_DIGESTS` | Limit engine usage to DIGESTS
`ENGINE_METHOD_PKEY_METHS` | Limit engine usage to PKEY_METHDS
`ENGINE_METHOD_PKEY_ASN1_METHS` | Limit engine usage to PKEY_ASN1_METHS
`ENGINE_METHOD_ALL` |
`ENGINE_METHOD_NONE` |

#### Other OpenSSL constants#

Constant | Description
--- | ---
`DH_CHECK_P_NOT_SAFE_PRIME` |
`DH_CHECK_P_NOT_PRIME` |
`DH_UNABLE_TO_CHECK_GENERATOR` |
`DH_NOT_SUITABLE_GENERATOR` |
`ALPN_ENABLED` |
`RSA_PKCS1_PADDING` |
`RSA_SSLV23_PADDING` |
`RSA_NO_PADDING` |
`RSA_PKCS1_OAEP_PADDING` |
`RSA_X931_PADDING` |
`RSA_PKCS1_PSS_PADDING` |
`RSA_PSS_SALTLEN_DIGEST` | Sets the salt length for `RSA_PKCS1_PSS_PADDING` to the digest size when signing or verifying.
`RSA_PSS_SALTLEN_MAX_SIGN` | Sets the salt length for `RSA_PKCS1_PSS_PADDING` to the maximum permissible value when signing data.
`RSA_PSS_SALTLEN_AUTO` | Causes the salt length for `RSA_PKCS1_PSS_PADDING` to be determined automatically when verifying a signature.
`POINT_CONVERSION_COMPRESSED` |
`POINT_CONVERSION_UNCOMPRESSED` |
`POINT_CONVERSION_HYBRID` |

#### Node.js crypto constants#

Constant | Description
--- | ---
`defaultCoreCipherList` | Specifies the built-in default cipher list used by Node.js.
`defaultCipherList` | Specifies the active default cipher list used by the current Node.js process.