Crypto#

Stability: 2 - Stable

Source Code: lib/crypto.js

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

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

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

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

Determining if crypto support is unavailable#

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

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

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

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

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

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

Asymmetric key types#

The following table lists the asymmetric key types recognized by the KeyObject API:

Key TypeDescriptionOID
'dh'Diffie-Hellman1.2.840.113549.1.3.1
'dsa'DSA1.2.840.10040.4.1
'ec'Elliptic curve1.2.840.10045.2.1
'ed25519'Ed255191.3.101.112
'ed448'Ed4481.3.101.113
'ml-dsa-44'1ML-DSA-442.16.840.1.101.3.4.3.17
'ml-dsa-65'1ML-DSA-652.16.840.1.101.3.4.3.18
'ml-dsa-87'1ML-DSA-872.16.840.1.101.3.4.3.19
'ml-kem-1024'1ML-KEM-10242.16.840.1.101.3.4.4.3
'ml-kem-512'1ML-KEM-5122.16.840.1.101.3.4.4.1
'ml-kem-768'1ML-KEM-7682.16.840.1.101.3.4.4.2
'rsa-pss'RSA PSS1.2.840.113549.1.1.10
'rsa'RSA1.2.840.113549.1.1.1
'x25519'X255191.3.101.110
'x448'X4481.3.101.111

Class: Certificate#

Added in: v0.11.8

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

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

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

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

History
VersionChanges
v15.0.0

The spkac argument can be an ArrayBuffer. Limited the size of the spkac argument to a maximum of 2**31 - 1 bytes.

v9.0.0

Added in: v9.0.0

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

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

History
VersionChanges
v15.0.0

The spkac argument can be an ArrayBuffer. Limited the size of the spkac argument to a maximum of 2**31 - 1 bytes.

v9.0.0

Added in: v9.0.0

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

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

History
VersionChanges
v15.0.0

The spkac argument can be an ArrayBuffer. Added encoding. Limited the size of the spkac argument to a maximum of 2**31 - 1 bytes.

v9.0.0

Added in: v9.0.0

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

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

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

Legacy API#

Stability: 0 - Deprecated

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

new crypto.Certificate()#

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

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

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

const cert1 = new Certificate();
const cert2 = Certificate();
certificate.exportChallenge(spkac[, encoding])#
Added in: v0.11.8 
const { Certificate } = await import('node:crypto');
const cert = Certificate();
const spkac = getSpkacSomehow();
const challenge = cert.exportChallenge(spkac);
console.log(challenge.toString('utf8'));
// Prints: the challenge as a UTF8 stringconst { Certificate } = require('node:crypto');
const cert = Certificate();
const spkac = getSpkacSomehow();
const challenge = cert.exportChallenge(spkac);
console.log(challenge.toString('utf8'));
// Prints: the challenge as a UTF8 string
certificate.exportPublicKey(spkac[, encoding])#
Added in: v0.11.8 
const { Certificate } = await import('node:crypto');
const cert = Certificate();
const spkac = getSpkacSomehow();
const publicKey = cert.exportPublicKey(spkac);
console.log(publicKey);
// Prints: the public key as <Buffer ...>const { Certificate } = require('node:crypto');
const cert = Certificate();
const spkac = getSpkacSomehow();
const publicKey = cert.exportPublicKey(spkac);
console.log(publicKey);
// Prints: the public key as <Buffer ...>
certificate.verifySpkac(spkac[, encoding])#
Added in: v0.11.8 
import { Buffer } from 'node:buffer';
const { Certificate } = await import('node:crypto');

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

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

Class: Cipheriv#

Added in: v0.1.94

Instances of the Cipheriv 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.createCipheriv() method is used to create Cipheriv instances. Cipheriv objects are not to be created directly using the new keyword.

Example: Using Cipheriv objects as streams:

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

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

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

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

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

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

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

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

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

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

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

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

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

Example: Using Cipheriv and piped streams:

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

import {
  pipeline,
} from 'node:stream';

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

cipher.final([outputEncoding])#

Added in: v0.1.94
  • outputEncoding <string> The encoding of the return value.
  • Returns: <Buffer> | <string> Any remaining enciphered contents. If outputEncoding is specified, a string is returned. If an outputEncoding is not provided, a Buffer is returned.

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

cipher.getAuthTag()#

Added in: v1.0.0
  • Returns: <Buffer> When using an authenticated encryption mode (GCM, CCM, OCB, and chacha20-poly1305 are currently supported), the cipher.getAuthTag() method returns a Buffer containing the authentication tag that has been computed from the given data.

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

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

cipher.setAAD(buffer[, options])#

Added in: v1.0.0

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

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

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

cipher.setAutoPadding([autoPadding])#

Added in: v0.7.1
  • autoPadding <boolean> Default: true
  • Returns: <Cipheriv> The same Cipheriv instance for method chaining.

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

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

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

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

History
VersionChanges
v6.0.0

The default inputEncoding changed from binary to utf8.

v0.1.94

Added in: v0.1.94

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: Decipheriv#

Added in: v0.1.94

Instances of the Decipheriv 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.createDecipheriv() method is used to create Decipheriv instances. Decipheriv objects are not to be created directly using the new keyword.

Example: Using Decipheriv objects as streams:

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

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

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

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

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

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

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

let decrypted = '';
decipher.on('readable', () => {
  let chunk;
  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 Decipheriv and piped streams:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

decipher.final([outputEncoding])#

Added in: v0.1.94
  • outputEncoding <string> The encoding of the return value.
  • Returns: <Buffer> | <string> Any remaining deciphered contents. If outputEncoding is specified, a string is returned. If an outputEncoding is not provided, a Buffer is returned.

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

decipher.setAAD(buffer[, options])#

History
VersionChanges
v15.0.0

The buffer argument can be a string or ArrayBuffer and is limited to no more than 2 ** 31 - 1 bytes.

v7.2.0

This method now returns a reference to decipher.

v1.0.0

Added in: v1.0.0

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

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

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

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

decipher.setAuthTag(buffer[, encoding])#

History
VersionChanges
v22.0.0, v20.13.0

Using GCM tag lengths other than 128 bits without specifying the authTagLength option when creating decipher is deprecated.

v15.0.0

The buffer argument can be a string or ArrayBuffer and is limited to no more than 2 ** 31 - 1 bytes.

v11.0.0

This method now throws if the GCM tag length is invalid.

v7.2.0

This method now returns a reference to decipher.

v1.0.0

Added in: v1.0.0

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

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

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

decipher.setAutoPadding([autoPadding])#

Added in: v0.7.1

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

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

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

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

History
VersionChanges
v6.0.0

The default inputEncoding changed from binary to utf8.

v0.1.94

Added in: v0.1.94

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.

Even if the underlying cipher implements authentication, the authenticity and integrity of the plaintext returned from this function may be uncertain at this time. For authenticated encryption algorithms, authenticity is generally only established when the application calls decipher.final().

Class: DiffieHellman#

Added in: v0.5.0

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

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

import assert from 'node:assert';

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

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

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

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

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

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

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

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

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

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

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

Added in: v0.5.0

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

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

diffieHellman.generateKeys([encoding])#

Added in: v0.5.0

Generates private and public Diffie-Hellman key values unless they have been generated or computed already, 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.

This function is a thin wrapper around DH_generate_key(). In particular, once a private key has been generated or set, calling this function only updates the public key but does not generate a new private key.

diffieHellman.getGenerator([encoding])#

Added in: v0.5.0

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

diffieHellman.getPrime([encoding])#

Added in: v0.5.0

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

diffieHellman.getPrivateKey([encoding])#

Added in: v0.5.0

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

diffieHellman.getPublicKey([encoding])#

Added in: v0.5.0

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

diffieHellman.setPrivateKey(privateKey[, encoding])#

Added in: v0.5.0

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.

This function does not automatically compute the associated public key. Either diffieHellman.setPublicKey() or diffieHellman.generateKeys() can be used to manually provide the public key or to automatically derive it.

diffieHellman.setPublicKey(publicKey[, encoding])#

Added in: v0.5.0

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

diffieHellman.verifyError#

Added in: v0.11.12

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

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

  • DH_CHECK_P_NOT_SAFE_PRIME
  • DH_CHECK_P_NOT_PRIME
  • DH_UNABLE_TO_CHECK_GENERATOR
  • DH_NOT_SUITABLE_GENERATOR

Class: DiffieHellmanGroup#

Added in: v0.7.5

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

const { createDiffieHellmanGroup } = await import('node:crypto');
const dh = createDiffieHellmanGroup('modp16');const { createDiffieHellmanGroup } = require('node:crypto');
const dh = createDiffieHellmanGroup('modp16');

The following groups are supported:

  • 'modp14' (2048 bits, RFC 3526 Section 3)
  • 'modp15' (3072 bits, RFC 3526 Section 4)
  • 'modp16' (4096 bits, RFC 3526 Section 5)
  • 'modp17' (6144 bits, RFC 3526 Section 6)
  • 'modp18' (8192 bits, RFC 3526 Section 7)

The following groups are still supported but deprecated (see Caveats):

  • 'modp1' (768 bits, RFC 2409 Section 6.1)
  • 'modp2' (1024 bits, RFC 2409 Section 6.2)
  • 'modp5' (1536 bits, RFC 3526 Section 2)

These deprecated groups might be removed in future versions of Node.js.

Class: ECDH#

Added in: v0.11.14

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

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

import assert from 'node:assert';

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

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

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

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

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

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

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

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

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

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

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

Added in: v10.0.0

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

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

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

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

Example (uncompressing a key):

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

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

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

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

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

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

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

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

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

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

History
VersionChanges
v10.0.0

Changed error format to better support invalid public key error.

v6.0.0

The default inputEncoding changed from binary to utf8.

v0.11.14

Added in: v0.11.14

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

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

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

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

Added in: v0.11.14

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

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

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

ecdh.getPrivateKey([encoding])#

Added in: v0.11.14

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

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

Added in: v0.11.14

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

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

ecdh.setPrivateKey(privateKey[, encoding])#

Added in: v0.11.14

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

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

ecdh.setPublicKey(publicKey[, encoding])#

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

Stability: 0 - Deprecated

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

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

Example (obtaining a shared secret):

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

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

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

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

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

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

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

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

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

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

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

Class: Hash#

Added in: v0.1.92

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

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

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

Example: Using Hash objects as streams:

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

const hash = createHash('sha256');

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

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

const hash = createHash('sha256');

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

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

Example: Using Hash and piped streams:

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

const hash = createHash('sha256');

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

const hash = createHash('sha256');

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

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

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

const hash = createHash('sha256');

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

const hash = createHash('sha256');

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

hash.copy([options])#

Added in: v13.1.0

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

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

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

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

const hash = createHash('sha256');

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

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

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

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

const hash = createHash('sha256');

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

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

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

// Etc.

hash.digest([encoding])#

Added in: v0.1.92

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

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

hash.update(data[, inputEncoding])#

History
VersionChanges
v6.0.0

The default inputEncoding changed from binary to utf8.

v0.1.92

Added in: v0.1.92

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

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

Class: Hmac#

Added in: v0.1.94

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

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

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

Example: Using Hmac objects as streams:

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

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

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

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

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

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

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

Example: Using Hmac and piped streams:

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

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

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

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

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

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

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

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

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

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

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

hmac.digest([encoding])#

Added in: v0.1.94

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

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

hmac.update(data[, inputEncoding])#

History
VersionChanges
v6.0.0

The default inputEncoding changed from binary to utf8.

v0.1.94

Added in: v0.1.94

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

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

Class: KeyObject#

History
VersionChanges
v24.6.0

Add support for ML-DSA keys.

v14.5.0, v12.19.0

Instances of this class can now be passed to worker threads using postMessage.

v11.13.0

This class is now exported.

v11.6.0

Added in: v11.6.0

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

Most applications should consider using the new KeyObject API instead of passing keys as strings or 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)#

Added in: v15.0.0

Example: Converting a CryptoKey instance to a KeyObject:

const { KeyObject } = await import('node:crypto');
const { subtle } = globalThis.crypto;

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 { KeyObject } = require('node:crypto');
const { subtle } = globalThis.crypto;

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

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

keyObject.asymmetricKeyDetails#

History
VersionChanges
v16.9.0

Expose RSASSA-PSS-params sequence parameters for RSA-PSS keys.

v15.7.0

Added in: v15.7.0

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

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

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

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

keyObject.asymmetricKeyType#

History
VersionChanges
v24.7.0

Add support for ML-KEM keys.

v24.6.0

Add support for ML-DSA keys.

v13.9.0, v12.17.0

Added support for 'dh'.

v12.0.0

Added support for 'rsa-pss'.

v12.0.0

This property now returns undefined for KeyObject instances of unrecognized type instead of aborting.

v12.0.0

Added support for 'x25519' and 'x448'.

v12.0.0

Added support for 'ed25519' and 'ed448'.

v11.6.0

Added in: v11.6.0

For asymmetric keys, this property represents the type of the key. See the supported asymmetric key types.

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

keyObject.equals(otherKeyObject)#

Added in: v17.7.0, v16.15.0

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

keyObject.export([options])#

History
VersionChanges
v15.9.0

Added support for 'jwk' format.

v11.6.0

Added in: v11.6.0

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.symmetricKeySize#

Added in: v11.6.0

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

keyObject.toCryptoKey(algorithm, extractable, keyUsages)#

Added in: v23.0.0, v22.10.0

Converts a KeyObject instance to a CryptoKey.

keyObject.type#

Added in: v11.6.0

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

Class: Sign#

Added in: v0.1.92

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

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

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

Example: Using Sign and Verify objects as streams:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

sign.sign(privateKey[, outputEncoding])#

History
VersionChanges
v15.0.0

The privateKey can also be an ArrayBuffer and CryptoKey.

v13.2.0, v12.16.0

This function now supports IEEE-P1363 DSA and ECDSA signatures.

v12.0.0

This function now supports RSA-PSS keys.

v11.6.0

This function now supports key objects.

v8.0.0

Support for RSASSA-PSS and additional options was added.

v0.1.92

Added in: v0.1.92

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

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

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

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

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

    • crypto.constants.RSA_PKCS1_PADDING (default)
    • crypto.constants.RSA_PKCS1_PSS_PADDING

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

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

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

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

sign.update(data[, inputEncoding])#

History
VersionChanges
v6.0.0

The default inputEncoding changed from binary to utf8.

v0.1.92

Added in: v0.1.92

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

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

Class: Verify#

Added in: v0.1.92

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

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

See Sign for examples.

verify.update(data[, inputEncoding])#

History
VersionChanges
v6.0.0

The default inputEncoding changed from binary to utf8.

v0.1.92

Added in: v0.1.92

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

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

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

History
VersionChanges
v15.0.0

The object can also be an ArrayBuffer and CryptoKey.

v13.2.0, v12.16.0

This function now supports IEEE-P1363 DSA and ECDSA signatures.

v12.0.0

This function now supports RSA-PSS keys.

v11.7.0

The key can now be a private key.

v8.0.0

Support for RSASSA-PSS and additional options was added.

v0.1.92

Added in: v0.1.92

Verifies the provided data using the given object and signature.

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

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

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

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

    • crypto.constants.RSA_PKCS1_PADDING (default)
    • crypto.constants.RSA_PKCS1_PSS_PADDING

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

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

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

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

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

Class: X509Certificate#

Added in: v15.6.0

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

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

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

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

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

console.log(x509.subject);

new X509Certificate(buffer)#

Added in: v15.6.0

x509.ca#

Added in: v15.6.0
  • Type: <boolean> Will be true if this is a Certificate Authority (CA) certificate.

x509.checkEmail(email[, options])#

History
VersionChanges
v18.0.0

The subject option now defaults to 'default'.

v17.5.0, v16.15.0

The subject option can now be set to 'default'.

v17.5.0, v16.14.1

The wildcards, partialWildcards, multiLabelWildcards, and singleLabelSubdomains options have been removed since they had no effect.

v15.6.0

Added in: v15.6.0

Checks whether the certificate matches the given email address.

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

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

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

x509.checkHost(name[, options])#

History
VersionChanges
v18.0.0

The subject option now defaults to 'default'.

v17.5.0, v16.15.0

The subject option can now be set to 'default'.

v15.6.0

Added in: v15.6.0

Checks whether the certificate matches the given host name.

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

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

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

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

x509.checkIP(ip)#

History
VersionChanges
v17.5.0, v16.14.1

The options argument has been removed since it had no effect.

v15.6.0

Added in: v15.6.0

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

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

x509.checkIssued(otherCert)#

Added in: v15.6.0

Checks whether this certificate was potentially issued by the given otherCert by comparing the certificate metadata.

This is useful for pruning a list of possible issuer certificates which have been selected using a more rudimentary filtering routine, i.e. just based on subject and issuer names.

Finally, to verify that this certificate's signature was produced by a private key corresponding to otherCert's public key use x509.verify(publicKey) with otherCert's public key represented as a KeyObject like so

if (!x509.verify(otherCert.publicKey)) {
  throw new Error('otherCert did not issue x509');
}

x509.checkPrivateKey(privateKey)#

Added in: v15.6.0

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

x509.fingerprint#

Added in: v15.6.0

The SHA-1 fingerprint of this certificate.

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

x509.fingerprint256#

Added in: v15.6.0

The SHA-256 fingerprint of this certificate.

x509.fingerprint512#

Added in: v17.2.0, v16.14.0

The SHA-512 fingerprint of this certificate.

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

x509.infoAccess#

History
VersionChanges
v17.3.1, v16.13.2

Parts of this string may be encoded as JSON string literals in response to CVE-2021-44532.

v15.6.0

Added in: v15.6.0

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

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

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

x509.issuer#

Added in: v15.6.0

The issuer identification included in this certificate.

x509.issuerCertificate#

Added in: v15.9.0

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

x509.keyUsage#

Added in: v15.6.0

An array detailing the key extended usages for this certificate.

x509.publicKey#

Added in: v15.6.0

The public key <KeyObject> for this certificate.

x509.raw#

Added in: v15.6.0

A Buffer containing the DER encoding of this certificate.

x509.serialNumber#

Added in: v15.6.0

The serial number of this certificate.

Serial numbers are assigned by certificate authorities and do not uniquely identify certificates. Consider using