Node.js v17.9.0 documentation

Determining if crypto support is unavailable#

It is possible for Node.js to be built without including support for the crypto module. In such cases, attempting to import from crypto or calling require('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('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('crypto');
} catch (err) {
  console.log('crypto support is disabled!');
}

Class: Certificate#

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 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])#

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

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

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

• 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 'buffer';
const { Certificate } = await import('crypto');

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

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

Legacy API#

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('crypto');

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

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

certificate.exportChallenge(spkac[, encoding])#

• 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('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('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])#

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

• 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 'buffer';
const { Certificate } = await import('crypto');

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

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

Class: Cipher#

• 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('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('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('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('fs');

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

const {
  scrypt,
  randomFill,
  createCipheriv,
} = require('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('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('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])#

• 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()#

• 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])#

• 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])#

• 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])#

• 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#

• 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 'buffer';
const {
  scryptSync,
  createDecipheriv
} = await import('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('crypto');
const { Buffer } = require('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 'buffer';
const {
  scryptSync,
  createDecipheriv
} = await import('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('fs');
const {
  scryptSync,
  createDecipheriv,
} = require('crypto');
const { Buffer } = require('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 'buffer';
const {
  scryptSync,
  createDecipheriv
} = await import('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('crypto');
const { Buffer } = require('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])#

• 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])#

• 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])#

• 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])#

• 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])#

• 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#

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 'assert';

const {
  createDiffieHellman
} = await import('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('assert');

const {
  createDiffieHellman,
} = require('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])#

• 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])#

• 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])#

• 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])#

• 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])#

• 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])#

• 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])#

• 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])#

• 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#

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 constants module):

• DH_CHECK_P_NOT_SAFE_PRIME
• DH_CHECK_P_NOT_PRIME
• DH_UNABLE_TO_CHECK_GENERATOR
• DH_NOT_SUITABLE_GENERATOR

Class: DiffieHellmanGroup#

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('crypto');
const dh = createDiffieHellmanGroup('modp1');const { createDiffieHellmanGroup } = require('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#

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 'assert';

const {
  createECDH
} = await import('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('assert');

const {
  createECDH,
} = require('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]]])#

• 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('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('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])#

• 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]])#

• 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])#

• 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])#

• 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])#

• 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])#

• 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('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('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#

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

const hash = createHash('sha256');

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

const hash = createHash('sha256');

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

const hash = createHash('sha256');

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

hash.copy([options])#

• 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('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('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])#

• 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])#

• 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#

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

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

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

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

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

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

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

hmac.digest([encoding])#

• 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])#

• 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#

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 Buffers 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)#

• key <CryptoKey>
• Returns: <KeyObject>

Example: Converting a CryptoKey instance to a KeyObject:

const { webcrypto, KeyObject } = await import('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('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#

• <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#

• <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])#

• 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)#

• 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#

• <number>

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

keyObject.type#

• <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#

• 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('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('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('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('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])#

• 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])#

• 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#

• 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])#

• 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])#

• 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#

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

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

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

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

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

console.log(x509.subject);

new X509Certificate(buffer)#

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

x509.ca#

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

x509.checkEmail(email[, options])#

• email <string>
• options <Object>
  • subject <string> 'default', 'always', or 'never'. Default: 'always'.
• 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 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 '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 'never', the certificate subject is never considered, even if the certificate contains no subject alternative names.

x509.checkHost(name[, options])#

• name <string>
• options <Object>
  • subject <string> 'default', 'always', or 'never'. Default: 'always'.
  • 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 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 '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 'never', the certificate subject is never considered, even if the certificate contains no subject alternative names.

x509.checkIP(ip)#

• 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)#

• otherCert <X509Certificate>
• Returns: <boolean>

Checks whether this certificate was issued by the given otherCert.

x509.checkPrivateKey(privateKey)#

• privateKey <KeyObject> A private key.
• Returns: <boolean>

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

x509.fingerprint#

• 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#

• Type: <string>

The SHA-256 fingerprint of this certificate.

x509.fingerprint512#

• 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#

• 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#

• Type: <string>

The issuer identification included in this certificate.

x509.issuerCertificate#

• Type: <X509Certificate>

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

x509.keyUsage#

• Type: <string[]>

An array detailing the key usages for this certificate.

x509.publicKey#

• Type: <KeyObject>

The public key <KeyObject> for this certificate.

x509.raw#

• Type: <Buffer>

A Buffer containing the DER encoding of this certificate.

x509.serialNumber#

• 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#

• Type: <string>

The complete subject of this certificate.

x509.subjectAltName#

• 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()#

• Type: <string>

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

x509.toLegacyObject()#

• Type: <Object>

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

x509.toString()#

• Type: <string>

Returns the PEM-encoded certificate.

x509.validFrom#

• Type: <string>

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

x509.validTo#

• Type: <string>

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

x509.verify(publicKey)#

• 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.

crypto module methods and properties#

crypto.constants#

• 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#

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#

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]])#

• 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])#

• 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])#

• 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])#

• 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 DataViews. 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])#

• 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])#

• 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 DataViews. 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])#

• 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])#

• 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)#

• name <string>
• Returns: <DiffieHellmanGroup>

An alias for crypto.getDiffieHellman()

crypto.createECDH(curveName)#

• 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])#

• 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 'process';
const {
  createHash
} = await import('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('fs');
const {
  createHash,
} = require('crypto');
const { argv } = require('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])#

• 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 'process';
const {
  createHmac
} = await import('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('fs');
const {
  createHmac,
} = require('crypto');
const { argv } = require('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)#

• 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)#

• 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])#

• 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])#

• 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])#

• 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)#

• 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)#

• 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 1, 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('crypto');

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

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

crypto.generateKeyPair(type, options, callback)#

• 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('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('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)#

• 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('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('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)#

• 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 1, 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('crypto');

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

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

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

• 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])#

• 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])#

• 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()#

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

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

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

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

crypto.getCurves()#

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

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

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

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

crypto.getDiffieHellman(groupName)#

• 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('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('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()#

• 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()#

• 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('crypto');

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

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

crypto.getRandomValues(typedArray)#

• typedArray <Buffer> | <TypedArray> | <DataView> | <ArrayBuffer>
• Returns: <Buffer> | <TypedArray> | <DataView> | <ArrayBuffer> Returns typedArray.