Table of Contents

• Web Crypto API
  • Examples
    • Generating keys
      • AES keys
      • Elliptic curve key pairs
      • HMAC keys
      • RSA key pairs
    • Encryption and decryption
    • Exporting and importing keys
    • Wrapping and unwrapping keys
    • Sign and verify
    • Deriving bits and keys
    • Digest
  • Algorithm Matrix
  • Class: Crypto
    • crypto.subtle
    • crypto.getRandomValues(typedArray)
  • Class: CryptoKey
    • cryptoKey.algorithm
    • cryptoKey.extractable
    • cryptoKey.type
    • cryptoKey.usages
  • Class: CryptoKeyPair
    • cryptoKeyPair.privateKey
    • cryptoKeyPair.publicKey
  • Class: SubtleCrypto
    • subtle.decrypt(algorithm, key, data)
    • subtle.deriveBits(algorithm, baseKey, length)
    • subtle.deriveKey(algorithm, baseKey, derivedKeyAlgorithm, extractable, keyUsages)
    • subtle.digest(algorithm, data)
    • subtle.encrypt(algorithm, key, data)
    • subtle.exportKey(format, key)
    • subtle.generateKey(algorithm, extractable, keyUsages)
    • subtle.importKey(format, keyData, algorithm, extractable, keyUsages)
    • subtle.sign(algorithm, key, data)
    • subtle.unwrapKey(format, wrappedKey, unwrappingKey, unwrapAlgo, unwrappedKeyAlgo, extractable, keyUsages)
    • subtle.verify(algorithm, key, signature, data)
    • subtle.wrapKey(format, key, wrappingKey, wrapAlgo)
  • Algorithm Parameters
    • Class: AesCbcParams
      • aesCbcParams.iv
      • aesCbcParams.name
    • Class: AesCtrParams
      • aesCtrParams.counter
      • aesCtrParams.length
      • aesCtrParams.name
    • Class: AesGcmParams
      • aesGcmParams.additionalData
      • aesGcmParams.iv
      • aesGcmParams.name
      • aesGcmParams.tagLength
    • Class: AesImportParams
      • 'aesImportParams.name`
    • Class: AesKeyGenParams
      • aesKeyGenParams.length
      • aesKeyGenParams.name
    • Class: AesKwParams
      • aesKwParams.name
    • Class: EcdhKeyDeriveParams
      • ecdhKeyDeriveParams.name
      • ecdhKeyDeriveParams.public
    • Class: EcdsaParams
      • ecdsaParams.hash
      • ecdsaParams.name
    • Class: EcKeyGenParams
      • ecKeyGenParams.name
      • ecKeyGenParams.namedCurve
    • Class: EcKeyImportParams
      • ecKeyImportParams.name
      • ecKeyImportParams.namedCurve
    • Class: HkdfParams
      • hkdfParams.hash
      • hkdfParams.info
      • hkdfParams.name
      • hkdfParams.salt
    • Class: HmacImportParams
      • 'hmacImportParams.hash`
      • hmacImportParams.length
      • hmacImportParams.name
    • Class: HmacKeyGenParams
      • hmacKeyGenParams.hash
      • hmacKeyGenParams.length
      • hmacKeyGenParams.name
    • Class: HmacParams
      • hmacParams.name
    • Class: Pbkdf2ImportParams
      • pbkdf2ImportParams.name
    • Class: Pbkdf2Params
      • pbkdb2Params.hash
      • pbkdf2Params.iterations
      • pbkdf2Params.name
      • pbkdf2Params.salt
    • Class: RsaHashedImportParams
      • rsaHashedImportParams.hash
      • rsaHashedImportParams.name
    • Class: RsaHashedKeyGenParams
      • rsaHashedKeyGenParams.hash
      • rsaHashedKeyGenParams.modulusLength
      • rsaHashedKeyGenParams.name
      • rsaHashedKeyGenParams.publicExponent
    • Class: RsaOaepParams
      • rsaOaepParams.label
      • rsaOaepParams.name
    • Class: RsaPssParams
      • rsaPssParams.name
      • rsaPssParams.saltLength
    • Class: RsaSignParams
      • rsaSignParams.name
  • Node.js-specific extensions
    • NODE-DH Algorithm
      • Class: NodeDhImportParams
        • nodeDhImportParams.name
      • Class: NodeDhKeyGenParams`
        • nodeDhKeyGenParams.generator
        • nodeDhKeyGenParams.group
        • nodeDhKeyGenParams.prime
        • nodeDhKeyGenParams.primeLength
      • Class: NodeDhDeriveBitsParams
        • nodeDhDeriveBitsParams.public
    • NODE-DSA Algorithm
      • Class: NodeDsaImportParams
        • nodeDsaImportParams.hash
        • nodeDsaImportParams.name
      • Class: NodeDsaKeyGenParams
        • nodeDsaKeyGenParams.divisorLength
        • nodeDsaKeyGenParams.hash
        • nodeDsaKeyGenParams.modulusLength
        • nodeDsaKeyGenParams.name
      • Class: NodeDsaSignParams
        • nodeDsaSignParams.name
    • NODE-SCRYPT Algorithm
      • Class: NodeScryptImportParams
        • nodeScryptImportParams.name
      • Class: NodeScryptParams
        • nodeScryptParams.encoding
        • nodeScryptParams.maxmem
        • nodeScryptParams.N
        • nodeScryptParams.p
        • nodeScryptParams.r
        • nodeScryptParams.salt

Web Crypto API#

Node.js provides an implementation of the standard Web Crypto API.

Use require('crypto').webcrypto to access this module.

const { subtle } = require('crypto').webcrypto;

(async function() {

  const key = await subtle.generateKey({
    name: 'hmac',
    length: 123
  }, true, ['sign', 'verify']);

  const digest = await subtle.sign({
    name: 'hmac'
  }, key, 'I love cupcakes');

})();

Examples#

Generating keys#

The <SubtleCrypto> class can be used to generate symmetric (secret) keys or asymmetric key pairs (public key and private key).

AES keys#

const { subtle } = require('crypto').webcrypto;

async function generateAesKey(length = 256) {
  const key = await subtle.generateKey({
    name: 'AES-CBC',
    length
  }, true, ['encrypt', 'decrypt']);

  return key;
}

Elliptic curve key pairs#

const { subtle } = require('crypto').webcrypto;

async function generateEcKey(namedCurve = 'P-521') {
  const {
    publicKey,
    privateKey
  } = await subtle.generateKey({
    name: 'ECDSA',
    namedCurve,
  }, true, ['sign', 'verify']);

  return { publicKey, privateKey };
}

HMAC keys#

const { subtle } = require('crypto').webcrypto;

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

  return key;
}

RSA key pairs#

const { subtle } = require('crypto').webcrypto;
const publicExponent = new Uint8Array([1, 0, 1]);

async function generateRsaKey(modulusLength = 2048, hash = 'SHA-256') {
  const {
    publicKey,
    privateKey
  } = await subtle.generateKey({
    name: 'RSASSA-PKCS1-v1_5',
    modulusLength,
    publicExponent,
    hash,
  }, true, ['sign', 'verify']);

  return { publicKey, privateKey };
}

Encryption and decryption#

const { subtle, getRandomValues } = require('crypto').webcrypto;

async function aesEncrypt(plaintext) {
  const ec = new TextEncoder();
  const key = await generateAesKey();
  const iv = getRandomValues(new Uint8Array(16));

  const ciphertext = await subtle.encrypt({
    name: 'AES-CBC',
    iv,
  }, key, ec.encode(plaintext));

  return {
    key,
    iv,
    ciphertext
  };
}

async function aesDecrypt(ciphertext, key, iv) {
  const dec = new TextDecoder();
  const plaintext = await subtle.decrypt({
    name: 'AES-CBC',
    iv,
  }, key, ciphertext);

  return dec.decode(plaintext);
}

Exporting and importing keys#

const { subtle } = require('crypto').webcrypto;

async function generateAndExportHmacKey(format = 'jwk', hash = 'SHA-512') {
  const key = await subtle.generateKey({
    name: 'HMAC',
    hash
  }, true, ['sign', 'verify']);

  return subtle.exportKey(format, key);
}

async function importHmacKey(keyData, format = 'jwk', hash = 'SHA-512') {
  const key = await subtle.importKey(format, keyData, {
    name: 'HMAC',
    hash
  }, true, ['sign', 'verify']);

  return key;
}

Wrapping and unwrapping keys#

const { subtle } = require('crypto').webcrypto;

async function generateAndWrapHmacKey(format = 'jwk', hash = 'SHA-512') {
  const [
    key,
    wrappingKey
  ] = await Promise.all([
    subtle.generateKey({
      name: 'HMAC', hash
    }, true, ['sign', 'verify']),
    subtle.generateKey({
      name: 'AES-KW',
      length: 256
    }, true, ['wrapKey', 'unwrapKey'])
  ]);

  const wrappedKey = await subtle.wrapKey(format, key, wrappingKey, 'AES-KW');

  return wrappedKey;
}

async function unwrapHmacKey(
  wrappedKey,
  wrappingKey,
  format = 'jwk',
  hash = 'SHA-512') {

  const key = await subtle.unwrapKey(
    format,
    wrappedKey,
    unwrappingKey,
    'AES-KW',
    { name: 'HMAC', hash },
    true,
    ['sign', 'verify']);

  return key;
}

Sign and verify#

const { subtle } = require('crypto').webcrypto;

async function sign(key, data) {
  const ec = new TextEncoder();
  const signature =
    await subtle.sign('RSASSA-PKCS1-v1_5', key, ec.encode(data));
  return signature;
}

async function verify(key, signature, data) {
  const ec = new TextEncoder();
  const verified =
    await subtle.verify(
      'RSASSA-PKCS1-v1_5',
      key,
      signature,
      ec.encode(data));
  return verified;
}

Deriving bits and keys#

const { subtle } = require('crypto').webcrypto;

async function pbkdf2(pass, salt, iterations = 1000, length = 256) {
  const ec = new TextEncoder();
  const key = await subtle.importKey(
    'raw',
    ec.encode(pass),
    'PBKDF2',
    false,
    ['deriveBits']);
  const bits = await subtle.deriveBits({
    name: 'PBKDF2',
    hash: 'SHA-512',
    salt: ec.encode(salt),
    iterations
  }, key, length);
  return bits;
}

async function pbkdf2Key(pass, salt, iterations = 1000, length = 256) {
  const ec = new TextEncoder();
  const keyMaterial = await subtle.importKey(
    'raw',
    ec.encode(pass),
    'PBKDF2',
    false,
    ['deriveBits']);
  const key = await subtle.deriveKey({
    name: 'PBKDF2',
    hash: 'SHA-512',
    salt: ec.encode(salt),
    iterations
  }, keyMaterial, {
    name: 'AES-GCM',
    length: 256
  }, true, ['encrypt', 'decrypt']);
  return key;
}

Digest#

const { subtle } = require('crypto').webcrypto;

async function digest(data, algorithm = 'SHA-512') {
  const ec = new TextEncoder();
  const digest = await subtle.digest(algorithm, ec.encode(data));
  return digest;
}

Algorithm Matrix#

The table details the algorithms supported by the Node.js Web Crypto API implementation and the APIs supported for each:

Algorithm	generateKey	exportKey	importKey	encrypt	decrypt	wrapKey	unwrapKey	deriveBits	deriveKey	sign	verify	digest
'RSASSA-PKCS1-v1_5'	✔	✔	✔							✔	✔
'RSA-PSS'	✔	✔	✔							✔	✔
'RSA-OAEP'	✔	✔	✔	✔	✔	✔	✔
'ECDSA'	✔	✔	✔							✔	✔
'ECDH'	✔	✔	✔					✔	✔
'AES-CTR'	✔	✔	✔	✔	✔	✔	✔
'AES-CBC'	✔	✔	✔	✔	✔	✔	✔
'AES-GCM'	✔	✔	✔	✔	✔	✔	✔
'AES-KW'	✔	✔	✔			✔	✔
'HMAC'	✔	✔	✔							✔	✔
'HKDF'		✔	✔					✔	✔
'PBKDF2'		✔	✔					✔	✔
'SHA-1'												✔
'SHA-256'												✔
'SHA-384'												✔
'SHA-512'												✔
'NODE-DSA'1	✔	✔	✔							✔	✔
'NODE-DH'1	✔	✔	✔					✔	✔

¹ Node.js-specific extension

Class: Crypto#

Calling require('crypto').webcrypto returns an instance of the Crypto class. Crypto is a singleton that provides access to the remainder of the crypto API.

crypto.subtle#

• Type: <SubtleCrypto>

Provides access to the SubtleCrypto API.

crypto.getRandomValues(typedArray)#

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

Generates cryptographically strong random values. The given typedArray is filled with random values, and a reference to typedArray is returned.

An error will be thrown if the given typedArray is larger than 65,536 bytes.

Class: CryptoKey#

cryptoKey.algorithm#

• Type: <AesKeyGenParams> | <RsaHashedKeyGenParams> | <EcKeyGenParams> | <HmacKeyGenParams> | <NodeDsaKeyGenParams> | <NodeDhKeyGenParams>

An object detailing the algorithm for which the key can be used along with additional algorithm-specific parameters.

Read-only.

cryptoKey.extractable#

• Type: <boolean>

When true, the <CryptoKey> can be extracted using either subtleCrypto.exportKey() or subtleCrypto.wrapKey().

Read-only.

cryptoKey.type#

• Type: <string> One of 'secret', 'private', or 'public'.

A string identifying whether the key is a symmetric ('secret') or asymmetric ('private' or 'public') key.

cryptoKey.usages#

• Type: <string[]>

An array of strings identifying the operations for which the key may be used.

The possible usages are:

• 'encrypt' - The key may be used to encrypt data.
• 'decrypt' - The key may be used to decrypt data.
• 'sign' - The key may be used to generate digital signatures.
• 'verify' - The key may be used to verify digital signatures.
• 'deriveKey' - The key may be used to derive a new key.
• 'deriveBits' - The key may be used to derive bits.
• 'wrapKey' - The key may be used to wrap another key.
• 'unwrapKey' - The key may be used to unwrap another key.

Valid key usages depend on the key algorithm (identified by cryptokey.algorithm.name).

Key Type	'encrypt'	'decrypt'	'sign'	'verify'	'deriveKey'	'deriveBits'	'wrapKey'	'unwrapKey'
'AES-CBC'	✔	✔					✔	✔
'AES-CTR'	✔	✔					✔	✔
'AES-GCM'	✔	✔					✔	✔
'AES-KW'							✔	✔
'ECDH'					✔	✔
'ECDSA'			✔	✔
'HDKF'					✔	✔
'HMAC'			✔	✔
'PBKDF2'					✔	✔
'RSA-OAEP'	✔	✔					✔	✔
'RSA-PSS'			✔	✔
'RSASSA-PKCS1-v1_5'			✔	✔
'NODE-DSA' 1			✔	✔
'NODE-DH' 1					✔	✔
'NODE-SCRYPT' 1					✔	✔

¹ Node.js-specific extension.

Class: CryptoKeyPair#

The CryptoKeyPair is a simple dictionary object with publicKey and privateKey properties, representing an asymmetric key pair.

cryptoKeyPair.privateKey#

• Type: <CryptoKey> A <CryptoKey> whose type will be 'private'.

cryptoKeyPair.publicKey#

• Type: <CryptoKey> A <CryptoKey> whose type will be 'public'.

Class: SubtleCrypto#

subtle.decrypt(algorithm, key, data)#

• algorithm: <RsaOaepParams> | <AesCtrParams> | <AesCbcParams> | <AesGcmParams>
• key: <CryptoKey>
• data: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>
• Returns: <Promise> containing <ArrayBuffer>

Using the method and parameters specified in algorithm and the keying material provided by key, subtle.decrypt() attempts to decipher the provided data. If successful, the returned promise will be resolved with an <ArrayBuffer> containing the plaintext result.

The algorithms currently supported include:

• 'RSA-OAEP'
• 'AES-CTR'
• 'AES-CBC'
• 'AES-GCM'

subtle.deriveBits(algorithm, baseKey, length)#

• algorithm: <EcdhKeyDeriveParams> | <HkdfParams> | <Pbkdf2Params> | <NodeDhDeriveBitsParams> | <NodeScryptParams>
• baseKey: <CryptoKey>
• length: <number>
• Returns: <Promise> containing <ArrayBuffer>

Using the method and parameters specified in algorithm and the keying material provided by baseKey, subtle.deriveBits() attempts to generate length bits. The Node.js implementation requires that length is a multiple of 8. If successful, the returned promise will be resolved with an <ArrayBuffer> containing the generated data.

The algorithms currently supported include:

• 'ECDH'
• 'HKDF'
• 'PBKDF2'
• 'NODE-DH'¹
• 'NODE-SCRYPT'¹

¹ Node.js-specific extension

subtle.deriveKey(algorithm, baseKey, derivedKeyAlgorithm, extractable, keyUsages)#

• algorithm: <EcdhKeyDeriveParams> | <HkdfParams> | <Pbkdf2Params> | <NodeDhDeriveBitsParams> | <NodeScryptParams>
• baseKey: <CryptoKey>
• derivedKeyAlgorithm: <HmacKeyGenParams> | <AesKeyGenParams>
• extractable: <boolean>
• keyUsages: <string[]> See Key usages.
• Returns: <Promise> containing <ArrayBuffer>

Using the method and parameters specified in algorithm, and the keying material provided by baseKey, subtle.deriveKey() attempts to generate a new <CryptoKey> based on the method and parameters in derivedKeyAlgorithm.

Calling subtle.deriveKey() is equivalent to calling subtle.deriveBits() to generate raw keying material, then passing the result into the subtle.importKey() method using the deriveKeyAlgorithm, extractable, and keyUsages parameters as input.

The algorithms currently supported include:

• 'ECDH'
• 'HKDF'
• 'PBKDF2'
• 'NODE-DH'¹
• 'NODE-SCRYPT'¹

¹ Node.js-specific extension

subtle.digest(algorithm, data)#

• algorithm: <string> | <Object>
• data: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>
• Returns: <Promise> containing <ArrayBuffer>

Using the method identified by algorithm, subtle.digest() attempts to generate a digest of data. If successful, the returned promise is resolved with an <ArrayBuffer> containing the computed digest.

If algorithm is provided as a <string>, it must be one of:

• 'SHA-1'
• 'SHA-256'
• 'SHA-384'
• 'SHA-512'

If algorithm is provided as an <Object>, it must have a name property whose value is one of the above.

subtle.encrypt(algorithm, key, data)#

• algorithm: <RsaOaepParams> | <AesCtrParams> | <AesCbcParams> | <AesGcmParams>
• key: <CryptoKey>
• Returns: <Promise> containing <ArrayBuffer>

Using the method and parameters specified by algorithm and the keying material provided by key, subtle.encrypt() attempts to encipher data. If successful, the returned promise is resolved with an <ArrayBuffer> containing the encrypted result.

The algorithms currently supported include:

• 'RSA-OAEP'
• 'AES-CTR'
• 'AES-CBC'
• 'AES-GCM'

subtle.exportKey(format, key)#

• format: <string> Must be one of 'raw', 'pkcs8', 'spki', 'jwk', or node.keyObject.
• key: <CryptoKey>
• Returns: <Promise> containing <ArrayBuffer>, or, if format is node.keyObject, a <KeyObject>.

Exports the given key into the specified format, if supported.

If the <CryptoKey> is not extractable, the returned promise will reject.

When format is either 'pkcs8' or 'spki' and the export is successful, the returned promise will be resolved with an <ArrayBuffer> containing the exported key data.

When format is 'jwk' and the export is successful, the returned promise will be resolved with a JavaScript object conforming to the JSON Web Key specification.

The special 'node.keyObject' value for format is a Node.js-specific extension that allows converting a <CryptoKey> into a Node.js <KeyObject>.

Key Type	'spki'	'pkcs8'	'jwk'	'raw'
'AES-CBC'			✔	✔
'AES-CTR'			✔	✔
'AES-GCM'			✔	✔
'AES-KW'			✔	✔
'ECDH'	✔	✔	✔	✔
'ECDSA'	✔	✔	✔	✔
'HDKF'
'HMAC'			✔	✔
'PBKDF2'
'RSA-OAEP'	✔	✔	✔
'RSA-PSS'	✔	✔	✔
'RSASSA-PKCS1-v1_5'	✔	✔	✔
'NODE-DSA' 1	✔	✔	✔
'NODE-DH' 1	✔	✔
'NODE-SCRYPT' 1

¹ Node.js-specific extension

subtle.generateKey(algorithm, extractable, keyUsages)#

• algorithm: <RsaHashedKeyGenParams> | <EcKeyGenParams> | <HmacKeyGenParams> | <AesKeyGenParams> | <NodeDsaKeyGenParams> | <NodeDhKeyGenParams>
• extractable: <boolean>
• keyUsages: <string[]> See Key usages.
• Returns: <Promise> containing <CryptoKey> | <CryptoKeyPair>

Using the method and parameters provided in algorithm, subtle.generateKey() attempts to generate new keying material. Depending the method used, the method may generate either a single <CryptoKey> or a <CryptoKeyPair>.

The <CryptoKeyPair> (public and private key) generating algorithms supported include:

• 'RSASSA-PKCS1-v1_5'
• 'RSA-PSS'
• 'RSA-OAEP'
• 'ECDSA'
• 'ECDH'
• 'NODE-DSA' ¹
• 'NODE-DH' ¹

The <CryptoKey> (secret key) generating algorithms supported include:

• 'HMAC'
• 'AES-CTR'
• 'AES-CBC'
• 'AES-GCM'
• 'AES-KW'

¹ Non-standard Node.js extension

subtle.importKey(format, keyData, algorithm, extractable, keyUsages)#

• format: <string> Must be one of 'raw', 'pkcs8', 'spki', 'jwk', or node.keyObject.
• keyData: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer> | <KeyObject>
• algorithm: <RsaHashedImportParams> | <EcKeyImportParams> | <HmacImportParams> | <AesImportParams> | <Pbkdf2ImportParams> | <NodeDsaImportParams> | <NodeDhImportParams> | <NodeScryptImportParams>
• extractable: <boolean>
• keyUsages: <string[]> See Key usages.
• Returns: <Promise> containing <CryptoKey>

The subtle.importKey() method attempts to interpret the provided keyData as the given format to create a <CryptoKey> instance using the provided algorithm, extractable, and keyUsages arguments. If the import is successful, the returned promise will be resolved with the created <CryptoKey>.

The special 'node.keyObject' value for format is a Node.js-specific extension that allows converting a Node.js <KeyObject> into a <CryptoKey>.

If importing a 'PBKDF2' key, extractable must be false.

The algorithms currently supported include:

Key Type	'spki'	'pkcs8'	'jwk'	'raw'
'AES-CBC'			✔	✔
'AES-CTR'			✔	✔
'AES-GCM'			✔	✔
'AES-KW'			✔	✔
'ECDH'	✔	✔	✔	✔
'ECDSA'	✔	✔	✔	✔
'HDKF'				✔
'HMAC'			✔	✔
'PBKDF2'				✔
'RSA-OAEP'	✔	✔	✔
'RSA-PSS'	✔	✔	✔
'RSASSA-PKCS1-v1_5'	✔	✔	✔
'NODE-DSA' 1	✔	✔	✔
'NODE-DH' 1	✔	✔
'NODE-SCRYPT' 1				✔

¹ Node.js-specific extension

subtle.sign(algorithm, key, data)#

• algorithm: <RsaSignParams> | <RsaPssParams> | <EcdsaParams> | <HmacParams> | <NodeDsaSignParams>
• key: <CryptoKey>
• data: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>
• Returns: <Promise> containing <ArrayBuffer>

Using the method and parameters given by algorithm and the keying material provided by key, subtle.sign() attempts to generate a cryptographic signature of data. If successful, the returned promise is resolved with an <ArrayBuffer> containing the generated signature.

The algorithms currently supported include:

• 'RSASSA-PKCS1-v1_5'
• 'RSA-PSS'
• 'ECDSA'
• 'HMAC'
• 'NODE-DSA'¹

¹ Non-standadrd Node.js extension

subtle.unwrapKey(format, wrappedKey, unwrappingKey, unwrapAlgo, unwrappedKeyAlgo, extractable, keyUsages)#

• format: <string> Must be one of 'raw', 'pkcs8', 'spki', or 'jwk'.
• wrappedKey: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>
• unwrappingKey: <CryptoKey>
• unwrapAlgo: <RsaOaepParams> | <AesCtrParams> | <AesCbcParams> | <AesGcmParams> | <AesKwParams>
• unwrappedKeyAlgo: <RsaHashedImportParams> | <EcKeyImportParams> | <HmacImportParams> | <AesImportParams>
• extractable: <boolean>
• keyUsages: <string[]> See Key usages.
• Returns: <Promise> containing <CryptoKey>

In cryptography, "wrapping a key" refers to exporting and then encrypting the keying material. The subtle.unwrapKey() method attempts to decrypt a wrapped key and create a <CryptoKey> instance. It is equivalent to calling subtle.decrypt() first on the encrypted key data (using the wrappedKey, unwrapAlgo, and unwrappingKey arguments as input) then passing the results in to the subtle.importKey() method using the unwrappedKeyAlgo, extractable, and keyUsages arguments as inputs. If successful, the returned promise is resolved with a <CryptoKey> object.

The wrapping algorithms currently supported include:

• 'RSA-OAEP'
• 'AES-CTR'¹
• 'AES-CBC'¹
• 'AES-GCM'¹
• 'AES-KW'¹

The unwrapped key algorithms supported include:

• 'RSASSA-PKCS1-v1_5'
• 'RSA-PSS'
• 'RSA-OAEP'
• 'ECDSA'
• 'ECDH'
• 'HMAC'
• 'AES-CTR'
• 'AES-CBC'
• 'AES-GCM'
• 'AES-KW'
• 'NODE-DSA'¹
• 'NODE-DH'¹

¹ Non-standard Node.js extension

subtle.verify(algorithm, key, signature, data)#

• algorithm: <RsaSignParams> | <RsaPssParams> | <EcdsaParams> | <HmacParams> | <NodeDsaSignParams>
• key: <CryptoKey>
• signature: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>
• data: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>
• Returns: <Promise> containing <boolean>

Using the method and parameters given in algorithm and the keying material provided by key, subtle.verify() attempts to verify that signature is a valid cryptographic signature of data. The returned promise is resolved with either true or false.

The algorithms currently supported include:

• 'RSASSA-PKCS1-v1_5'
• 'RSA-PSS'
• 'ECDSA'
• 'HMAC'
• 'NODE-DSA'¹

¹ Non-standard Node.js extension

subtle.wrapKey(format, key, wrappingKey, wrapAlgo)#

• format: <string> Must be one of 'raw', 'pkcs8', 'spki', or 'jwk'.
• key: <CryptoKey>
• wrappingKey: <CryptoKey>
• wrapAlgo: <RsaOaepParams> | <AesCtrParams> | <AesCbcParams> | <AesGcmParams> | <AesKwParams>
• Returns: <Promise> containing <ArrayBuffer>

In cryptography, "wrapping a key" refers to exporting and then encrypting the keying material. The subtle.wrapKey() method exports the keying material into the format identified by format, then encrypts it using the method and parameters specified by wrapAlgo and the keying material provided by wrappingKey. It is the equivalent to calling subtle.exportKey() using format and key as the arguments, then passing the result to the subtle.encrypt() method using wrappingKey and wrapAlgo as inputs. If successful, the returned promise will be resolved with an <ArrayBuffer> containing the encrypted key data.

The wrapping algorithms currently supported include:

• 'RSA-OAEP'
• 'AES-CTR'
• 'AES-CBC'
• 'AES-GCM'
• 'AES-KW'

Algorithm Parameters#

The algorithm parameter objects define the methods and parameters used by the various <SubtleCrypto> methods. While described here as "classes", they are simple JavaScript dictionary objects.

Class: AesCbcParams#

aesCbcParams.iv#

• Type: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>

Provides the initialization vector. It must be exactly 16-bytes in length and should be unpredictable and cryptographically random.

aesCbcParams.name#

• Type: <string> Must be 'AES-CBC'.

Class: AesCtrParams#

aesCtrParams.counter#

• Type: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>

The initial value of the counter block. This must be exactly 16 bytes long.

The AES-CTR method uses the rightmost length bits of the block as the counter and the remaining bits as the nonce.

aesCtrParams.length#

• Type: <number> The number of bits in the aesCtrParams.counter that are to be used as the counter.

aesCtrParams.name#

• Type: <string> Must be 'AES-CTR'.

Class: AesGcmParams#

aesGcmParams.additionalData#

• Type: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer> | <undefined>

With the AES-GCM method, the additionalData is extra input that is not encrypted but is included in the authentication of the data. The use of additionalData is optional.

aesGcmParams.iv#

• Type: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>

The initialization vector must be unique for every encryption operation using a given key. It is recommended by the AES-GCM specification that this contain at least 12 random bytes.

aesGcmParams.name#

• Type: <string> Must be 'AES-GCM'.

aesGcmParams.tagLength#

• Type: <number> The size in bits of the generated authentication tag. This values must be one of 32, 64, 96, 104, 112, 120, or 128. Default: 128.

Class: AesImportParams#

'aesImportParams.name`#

• Type: <string> Must be one of 'AES-CTR', 'AES-CBC', 'AES-GCM', or 'AES-KW'.

Class: AesKeyGenParams#

aesKeyGenParams.length#

• Type: <number>

The length of the AES key to be generated. This must be either 128, 192, or 256.

aesKeyGenParams.name#

• Type: <string> Must be one of 'AES-CBC', 'AES-CTR', 'AES-GCM', or 'AES-KW'

Class: AesKwParams#

aesKwParams.name#

• Type: <string> Must be 'AES-KW'.

Class: EcdhKeyDeriveParams#

ecdhKeyDeriveParams.name#

• Type: <string> Must be 'ECDH'.

ecdhKeyDeriveParams.public#

• Type: <CryptoKey>

ECDH key derivation operates by taking as input one parties private key and another parties public key -- using both to generate a common shared secret. The ecdhKeyDeriveParams.public property is set to the other parties public key.

Class: EcdsaParams#

ecdsaParams.hash#

• Type: <string> | <Object>

If represented as a <string>, the value must be one of:

• 'SHA-1'
• 'SHA-256'
• 'SHA-384'
• 'SHA-512'

If represented as an <Object>, the object must have a name property whose value is one of the above listed values.

ecdsaParams.name#

• Type: <string> Must be 'ECDSA'.

Class: EcKeyGenParams#

ecKeyGenParams.name#

• Type: <string> Must be one of 'ECDSA' or 'ECDH'.

ecKeyGenParams.namedCurve#

• Type: <string> Must be one of 'P-256', 'P-384' or 'P-521'.

Class: EcKeyImportParams#

ecKeyImportParams.name#

• Type: <string> Must be one of 'ECDSA' or 'ECDH'.

ecKeyImportParams.namedCurve#

• Type: <string> Must be one of 'P-256', 'P-384' or 'P-521'.

Class: HkdfParams#

hkdfParams.hash#

• Type: <string> | <Object>

If represented as a <string>, the value must be one of:

• 'SHA-1'
• 'SHA-256'
• 'SHA-384'
• 'SHA-512'

If represented as an <Object>, the object must have a name property whose value is one of the above listed values.

hkdfParams.info#

• Type: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>

Provides application-specific contextual input to the HKDF algorithm. This can be zero-length but must be provided.

hkdfParams.name#

• Type: <string> Must be 'HKDF'.

hkdfParams.salt#

• Type: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>

The salt value significantly improves the strength of the HKDF algorithm. It should be random or pseudo-random and should be the same length as the output of the digest function (for instance, if using 'SHA-256' as the digest, the salt should be 256-bits of random data).

Class: HmacImportParams#

'hmacImportParams.hash`#

• Type: <string> | <Object>

If represented as a <string>, the value must be one of:

• 'SHA-1'
• 'SHA-256'
• 'SHA-384'
• 'SHA-512'

If represented as an <Object>, the object must have a name property whose value is one of the above listed values.

hmacImportParams.length#

• Type: <number>

The optional number of bits in the HMAC key. This is optional and should be omitted for most cases.

hmacImportParams.name#

• Type: <string> Must be 'HMAC'.

Class: HmacKeyGenParams#

hmacKeyGenParams.hash#

• Type: <string> | <Object>

If represented as a <string>, the value must be one of:

• 'SHA-1'
• 'SHA-256'
• 'SHA-384'
• 'SHA-512'

If represented as an <Object>, the object must have a name property whose value is one of the above listed values.

hmacKeyGenParams.length#

• Type: <number>

The number of bits to generate for the HMAC key. If omitted, the length will be determined by the hash algorithm used. This is optional and should be omitted for most cases.

hmacKeyGenParams.name#

• Type: <string> Must be 'HMAC'.

Class: HmacParams#

hmacParams.name#

• Type: <string> Must be 'HMAC.

Class: Pbkdf2ImportParams#

pbkdf2ImportParams.name#

• Type: <string> Must be 'PBKDF2'

Class: Pbkdf2Params#

pbkdb2Params.hash#

• Type: <string> | <Object>

If represented as a <string>, the value must be one of:

• 'SHA-1'
• 'SHA-256'
• 'SHA-384'
• 'SHA-512'

If represented as an <Object>, the object must have a name property whose value is one of the above listed values.

pbkdf2Params.iterations#

• Type: <number>

The number of iterations the PBKDF2 algorithm should make when deriving bits.

pbkdf2Params.name#

• Type: <string> Must be 'PBKDF2'.

pbkdf2Params.salt#

• Type: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>

Should be at least 16 random or pseudo-random bytes.

Class: RsaHashedImportParams#

rsaHashedImportParams.hash#

• Type: <string> | <Object>

If represented as a <string>, the value must be one of:

• 'SHA-1'
• 'SHA-256'
• 'SHA-384'
• 'SHA-512'

If represented as an <Object>, the object must have a name property whose value is one of the above listed values.

rsaHashedImportParams.name#

• Type: <string> Must be one of 'RSASSA-PKCS1-v1_5', 'RSA-PSS', or 'RSA-OAEP'.

Class: RsaHashedKeyGenParams#

rsaHashedKeyGenParams.hash#

• Type: <string> | <Object>

If represented as a <string>, the value must be one of:

• 'SHA-1'
• 'SHA-256'
• 'SHA-384'
• 'SHA-512'

If represented as an <Object>, the object must have a name property whose value is one of the above listed values.

rsaHashedKeyGenParams.modulusLength#

• Type: <number>

The length in bits of the RSA modulus. As a best practice, this should be at least 2048.

rsaHashedKeyGenParams.name#

• Type: <string> Must be one of 'RSASSA-PKCS1-v1_5', 'RSA-PSS', or 'RSA-OAEP'.

rsaHashedKeyGenParams.publicExponent#

• Type: <Uint8Array>

The RSA public exponent. This must be a <Uint8Array> containing a big-endian, unsigned integer that must fit within 32-bits. The <Uint8Array> may contain an arbitrary number of leading zero-bits. The value must be a prime number. Unless there is reason to use a different value, use new Uint8Array([1, 0, 1]) (65537) as the public exponent.

Class: RsaOaepParams#

rsaOaepParams.label#

• Type: <ArrayBuffer> | <TypedArray> | <DataView> | <Buffer>

An additional collection of bytes that will not be encrypted, but will be bound to the generated ciphertext.

The rsaOaepParams.label parameter is optional.

rsaOaepParams.name#

• Type: <string> must be 'RSA-OAEP'.

Class: RsaPssParams#

rsaPssParams.name#

• Type: <string> Must be 'RSA-PSS'.

rsaPssParams.saltLength#

• Type: <number>

The length (in bytes) of the random salt to use.

Class: RsaSignParams#

rsaSignParams.name#

• Type: <string> Must be 'RSASSA-PKCS1-v1_5'

Node.js-specific extensions#

The Node.js Web Crypto API extends various aspects of the Web Crypto API. These extensions are consistently identified by prepending names with the node. prefix. For instance, the node.keyObject key format can be used with the subtle.exportKey() and subtle.importKey() methods to convert between a WebCrypto <CryptoKey> object and a Node.js <KeyObject>.

Care should be taken when using Node.js-specific extensions as they are not supported by other WebCrypto implementations and reduce the portability of code to other environments.

NODE-DH Algorithm#

The NODE-DH algorithm is the common implementation of Diffie-Hellman key agreement.

Class: NodeDhImportParams#

nodeDhImportParams.name#

• Type: <string> Must be 'NODE-DH'.

Class: NodeDhKeyGenParams`#

nodeDhKeyGenParams.generator#

• Type: <number> A custom generator.

nodeDhKeyGenParams.group#

• Type: <string> The Diffie-Hellman group name.

nodeDhKeyGenParams.prime#

• Type: <Buffer> The prime parameter.

nodeDhKeyGenParams.primeLength#

• Type: <number> The length in bits of the prime.

Class: NodeDhDeriveBitsParams#

nodeDhDeriveBitsParams.public#

• Type: <CryptoKey> The other parties public key.

NODE-DSA Algorithm#

The NODE-DSA algorithm is the common implementation of the DSA digital signature algorithm.

Class: NodeDsaImportParams#

nodeDsaImportParams.hash#

• Type: <string> | <Object>

If represented as a <string>, the value must be one of:

• 'SHA-1'
• 'SHA-256'
• 'SHA-384'
• 'SHA-512'

If represented as an <Object>, the object must have a name property whose value is one of the above listed values.

nodeDsaImportParams.name#

• Type: <string> Must be 'NODE-DSA'.

Class: NodeDsaKeyGenParams#

nodeDsaKeyGenParams.divisorLength#

• Type: <number>

The optional length in bits of the DSA divisor.

nodeDsaKeyGenParams.hash#

• Type: <string> | <Object>

If represented as a <string>, the value must be one of:

• 'SHA-1'
• 'SHA-256'
• 'SHA-384'
• 'SHA-512'

If represented as an <Object>, the object must have a name property whose value is one of the above listed values.

nodeDsaKeyGenParams.modulusLength#

• Type: <number>

The length in bits of the DSA modulus. As a best practice, this should be at least 2048.

nodeDsaKeyGenParams.name#

• Type: <string> Must be 'NODE-DSA'.

Class: NodeDsaSignParams#

nodeDsaSignParams.name#

• Type: <string> Must be 'NODE-DSA'

NODE-SCRYPT Algorithm#

The NODE-SCRYPT algorithm is the common implementation of the scrypt key derivation algorithm.

Class: NodeScryptImportParams#

nodeScryptImportParams.name#

• Type: <string> Must be 'NODE-SCRYPT'.

Class: NodeScryptParams#

nodeScryptParams.encoding#

• Type: <string> The string encoding when salt is a string.

nodeScryptParams.maxmem#

• Type: <number> Memory upper bound. It is an error when (approximately) 127 * N * r > maxmem. Default: 32 * 1024 * 1024.

nodeScryptParams.N#

• Type: <number> The CPU/memory cost parameter. Must e a power of two greater than 1. Default 16384.

nodeScryptParams.p#

• Type: <number> Parallelization parameter. Default 1.

nodeScryptParams.r#

• Type: <number> Block size parameter. Default: 8.

nodeScryptParams.salt#

• Type: <string> | <ArrayBuffer> | <Buffer> | <TypedArray> | <DataView>