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Node.js v10.17.0-test201912065dae3ef88b Documentation
Table of Contents
-
- Determining if crypto support is unavailable
-
- diffieHellman.computeSecret(otherPublicKey[, inputEncoding][, outputEncoding])
- diffieHellman.generateKeys([encoding])
- diffieHellman.getGenerator([encoding])
- diffieHellman.getPrime([encoding])
- diffieHellman.getPrivateKey([encoding])
- diffieHellman.getPublicKey([encoding])
- diffieHellman.setPrivateKey(privateKey[, encoding])
- diffieHellman.setPublicKey(publicKey[, encoding])
- diffieHellman.verifyError
-
- Class Method: ECDH.convertKey(key, curve[, inputEncoding[, outputEncoding[, format]]])
- ecdh.computeSecret(otherPublicKey[, inputEncoding][, outputEncoding])
- ecdh.generateKeys([encoding[, format]])
- ecdh.getPrivateKey([encoding])
- ecdh.getPublicKey([encoding][, format])
- ecdh.setPrivateKey(privateKey[, encoding])
- ecdh.setPublicKey(publicKey[, encoding])
-
crypto
module methods and properties- crypto.constants
- crypto.DEFAULT_ENCODING
- crypto.fips
- crypto.createCipher(algorithm, password[, options])
- crypto.createCipheriv(algorithm, key, iv[, options])
- crypto.createCredentials(details)
- crypto.createDecipher(algorithm, password[, options])
- crypto.createDecipheriv(algorithm, key, iv[, options])
- crypto.createDiffieHellman(prime[, primeEncoding][, generator][, generatorEncoding])
- crypto.createDiffieHellman(primeLength[, generator])
- crypto.createECDH(curveName)
- crypto.createHash(algorithm[, options])
- crypto.createHmac(algorithm, key[, options])
- crypto.createSign(algorithm[, options])
- crypto.createVerify(algorithm[, options])
- crypto.generateKeyPair(type, options, callback)
- crypto.generateKeyPairSync(type, options)
- crypto.getCiphers()
- crypto.getCurves()
- crypto.getDiffieHellman(groupName)
- crypto.getFips()
- crypto.getHashes()
- crypto.pbkdf2(password, salt, iterations, keylen, digest, callback)
- crypto.pbkdf2Sync(password, salt, iterations, keylen, digest)
- crypto.privateDecrypt(privateKey, buffer)
- crypto.privateEncrypt(privateKey, buffer)
- crypto.publicDecrypt(key, buffer)
- crypto.publicEncrypt(key, buffer)
- crypto.randomBytes(size[, callback])
- crypto.randomFillSync(buffer[, offset][, size])
- crypto.randomFill(buffer[, offset][, size], callback)
- crypto.scrypt(password, salt, keylen[, options], callback)
- crypto.scryptSync(password, salt, keylen[, options])
- crypto.setEngine(engine[, flags])
- crypto.setFips(bool)
- crypto.timingSafeEqual(a, b)
Crypto#
The crypto
module provides cryptographic functionality that includes a set of
wrappers for OpenSSL's hash, HMAC, cipher, decipher, sign, and verify functions.
Use require('crypto')
to access this module.
const crypto = require('crypto');
const secret = 'abcdefg';
const hash = crypto.createHmac('sha256', secret)
.update('I love cupcakes')
.digest('hex');
console.log(hash);
// Prints:
// c0fa1bc00531bd78ef38c628449c5102aeabd49b5dc3a2a516ea6ea959d6658e
Determining if crypto support is unavailable#
It is possible for Node.js to be built without including support for the
crypto
module. In such cases, calling require('crypto')
will result in an
error being thrown.
let crypto;
try {
crypto = require('crypto');
} catch (err) {
console.log('crypto support is disabled!');
}
Class: Certificate#
SPKAC is a Certificate Signing Request mechanism originally implemented by
Netscape and was specified formally as part of HTML5's keygen
element.
Note that <keygen>
is deprecated since HTML 5.2 and new projects
should not use this element anymore.
The crypto
module provides the Certificate
class for working with SPKAC
data. The most common usage is handling output generated by the HTML5
<keygen>
element. Node.js uses OpenSSL's SPKAC implementation internally.
Certificate.exportChallenge(spkac)#
spkac
<string> | <Buffer> | <TypedArray> | <DataView>- Returns: <Buffer> The challenge component of the
spkac
data structure, which includes a public key and a challenge.
const { Certificate } = require('crypto');
const spkac = getSpkacSomehow();
const challenge = Certificate.exportChallenge(spkac);
console.log(challenge.toString('utf8'));
// Prints: the challenge as a UTF8 string
Certificate.exportPublicKey(spkac[, encoding])#
spkac
<string> | <Buffer> | <TypedArray> | <DataView>encoding
<string> The encoding of thespkac
string.- Returns: <Buffer> The public key component of the
spkac
data structure, which includes a public key and a challenge.
const { Certificate } = require('crypto');
const spkac = getSpkacSomehow();
const publicKey = Certificate.exportPublicKey(spkac);
console.log(publicKey);
// Prints: the public key as <Buffer ...>
Certificate.verifySpkac(spkac)#
spkac
<Buffer> | <TypedArray> | <DataView>- Returns: <boolean>
true
if the givenspkac
data structure is valid,false
otherwise.
const { Certificate } = require('crypto');
const spkac = getSpkacSomehow();
console.log(Certificate.verifySpkac(Buffer.from(spkac)));
// Prints: true or false
Legacy API#
As a still supported legacy interface, it is possible (but not recommended) 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 crypto = require('crypto');
const cert1 = new crypto.Certificate();
const cert2 = crypto.Certificate();
certificate.exportChallenge(spkac)#
spkac
<string> | <Buffer> | <TypedArray> | <DataView>- Returns: <Buffer> The challenge component of the
spkac
data structure, which includes a public key and a challenge.
const cert = require('crypto').Certificate();
const spkac = getSpkacSomehow();
const challenge = cert.exportChallenge(spkac);
console.log(challenge.toString('utf8'));
// Prints: the challenge as a UTF8 string
certificate.exportPublicKey(spkac)#
spkac
<string> | <Buffer> | <TypedArray> | <DataView>- Returns: <Buffer> The public key component of the
spkac
data structure, which includes a public key and a challenge.
const cert = require('crypto').Certificate();
const spkac = getSpkacSomehow();
const publicKey = cert.exportPublicKey(spkac);
console.log(publicKey);
// Prints: the public key as <Buffer ...>
certificate.verifySpkac(spkac)#
spkac
<Buffer> | <TypedArray> | <DataView>- Returns: <boolean>
true
if the givenspkac
data structure is valid,false
otherwise.
const cert = require('crypto').Certificate();
const spkac = getSpkacSomehow();
console.log(cert.verifySpkac(Buffer.from(spkac)));
// Prints: true or false
Class: Cipher#
Instances of the Cipher
class are used to encrypt data. The class can be
used in one of two ways:
- As a stream that is both readable and writable, where plain unencrypted data is written to produce encrypted data on the readable side, or
- Using the
cipher.update()
andcipher.final()
methods to produce the encrypted data.
The crypto.createCipher()
or crypto.createCipheriv()
methods are
used to create Cipher
instances. Cipher
objects are not to be created
directly using the new
keyword.
Example: Using Cipher
objects as streams:
const crypto = require('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 async `crypto.scrypt()` instead.
const key = crypto.scryptSync(password, 'salt', 24);
// Use `crypto.randomBytes()` to generate a random iv instead of the static iv
// shown here.
const iv = Buffer.alloc(16, 0); // Initialization vector.
const cipher = crypto.createCipheriv(algorithm, key, iv);
let encrypted = '';
cipher.on('readable', () => {
let chunk;
while (null !== (chunk = cipher.read())) {
encrypted += chunk.toString('hex');
}
});
cipher.on('end', () => {
console.log(encrypted);
// Prints: e5f79c5915c02171eec6b212d5520d44480993d7d622a7c4c2da32f6efda0ffa
});
cipher.write('some clear text data');
cipher.end();
Example: Using Cipher
and piped streams:
const crypto = require('crypto');
const fs = require('fs');
const algorithm = 'aes-192-cbc';
const password = 'Password used to generate key';
// Use the async `crypto.scrypt()` instead.
const key = crypto.scryptSync(password, 'salt', 24);
// Use `crypto.randomBytes()` to generate a random iv instead of the static iv
// shown here.
const iv = Buffer.alloc(16, 0); // Initialization vector.
const cipher = crypto.createCipheriv(algorithm, key, iv);
const input = fs.createReadStream('test.js');
const output = fs.createWriteStream('test.enc');
input.pipe(cipher).pipe(output);
Example: Using the cipher.update()
and cipher.final()
methods:
const crypto = require('crypto');
const algorithm = 'aes-192-cbc';
const password = 'Password used to generate key';
// Use the async `crypto.scrypt()` instead.
const key = crypto.scryptSync(password, 'salt', 24);
// Use `crypto.randomBytes` to generate a random iv instead of the static iv
// shown here.
const iv = Buffer.alloc(16, 0); // Initialization vector.
const cipher = crypto.createCipheriv(algorithm, key, iv);
let encrypted = cipher.update('some clear text data', 'utf8', 'hex');
encrypted += cipher.final('hex');
console.log(encrypted);
// Prints: e5f79c5915c02171eec6b212d5520d44480993d7d622a7c4c2da32f6efda0ffa
cipher.final([outputEncoding])#
outputEncoding
<string> The encoding of the return value.- Returns: <Buffer> | <string> Any remaining enciphered contents.
If
outputEncoding
is specified, a string is returned. If anoutputEncoding
is not provided, aBuffer
is returned.
Once the cipher.final()
method has been called, the Cipher
object can no
longer be used to encrypt data. Attempts to call cipher.final()
more than
once will result in an error being thrown.
cipher.setAAD(buffer[, options])#
buffer
<Buffer>-
options
<Object>stream.transform
optionsplaintextLength
<number>
- Returns: <Cipher> for method chaining.
When using an authenticated encryption mode (GCM
, CCM
and OCB
are
currently supported), the cipher.setAAD()
method sets the value used for the
additional authenticated data (AAD) input parameter.
The options
argument 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.getAuthTag()#
- Returns: <Buffer> When using an authenticated encryption mode (
GCM
,CCM
andOCB
are currently supported), thecipher.getAuthTag()
method returns aBuffer
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.
cipher.setAutoPadding([autoPadding])#
When using block encryption algorithms, the Cipher
class will automatically
add padding to the input data to the appropriate block size. To disable the
default padding call cipher.setAutoPadding(false)
.
When autoPadding
is false
, the length of the entire input data must be a
multiple of the cipher's block size or cipher.final()
will throw an error.
Disabling automatic padding is useful for non-standard padding, for instance
using 0x0
instead of PKCS padding.
The cipher.setAutoPadding()
method must be called before
cipher.final()
.
cipher.update(data[, inputEncoding][, outputencoding])#
data
<string> | <Buffer> | <TypedArray> | <DataView>inputEncoding
<string> The encoding of the data.outputEncoding
<string> The encoding of the return value.- Returns: <Buffer> | <string>
Updates the cipher with data
. If the inputEncoding
argument is given,
the data
argument is a string using the specified encoding. If the inputEncoding
argument is not given, data
must be a Buffer
, TypedArray
, or
DataView
. If data
is a Buffer
, TypedArray
, or DataView
, then
inputEncoding
is ignored.
The outputEncoding
specifies the output format of the enciphered
data. If the outputEncoding
is specified, a string using the specified encoding is returned. If no
outputEncoding
is provided, a Buffer
is returned.
The cipher.update()
method can be called multiple times with new data until
cipher.final()
is called. Calling cipher.update()
after
cipher.final()
will result in an error being thrown.
Class: Decipher#
Instances of the Decipher
class are used to decrypt data. The class can be
used in one of two ways:
- As a stream that is both readable and writable, where plain encrypted data is written to produce unencrypted data on the readable side, or
- Using the
decipher.update()
anddecipher.final()
methods to produce the unencrypted data.
The crypto.createDecipher()
or crypto.createDecipheriv()
methods are
used to create Decipher
instances. Decipher
objects are not to be created
directly using the new
keyword.
Example: Using Decipher
objects as streams:
const crypto = require('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 = crypto.scryptSync(password, 'salt', 24);
// The IV is usually passed along with the ciphertext.
const iv = Buffer.alloc(16, 0); // Initialization vector.
const decipher = crypto.createDecipheriv(algorithm, key, iv);
let decrypted = '';
decipher.on('readable', () => {
while (null !== (chunk = decipher.read())) {
decrypted += chunk.toString('utf8');
}
});
decipher.on('end', () => {
console.log(decrypted);
// Prints: some clear text data
});
// Encrypted with same algorithm, key and iv.
const encrypted =
'e5f79c5915c02171eec6b212d5520d44480993d7d622a7c4c2da32f6efda0ffa';
decipher.write(encrypted, 'hex');
decipher.end();
Example: Using Decipher
and piped streams:
const crypto = require('crypto');
const fs = require('fs');
const algorithm = 'aes-192-cbc';
const password = 'Password used to generate key';
// Use the async `crypto.scrypt()` instead.
const key = crypto.scryptSync(password, 'salt', 24);
// The IV is usually passed along with the ciphertext.
const iv = Buffer.alloc(16, 0); // Initialization vector.
const decipher = crypto.createDecipheriv(algorithm, key, iv);
const input = fs.createReadStream('test.enc');
const output = fs.createWriteStream('test.js');
input.pipe(decipher).pipe(output);
Example: Using the decipher.update()
and decipher.final()
methods:
const crypto = require('crypto');
const algorithm = 'aes-192-cbc';
const password = 'Password used to generate key';
// Use the async `crypto.scrypt()` instead.
const key = crypto.scryptSync(password, 'salt', 24);
// The IV is usually passed along with the ciphertext.
const iv = Buffer.alloc(16, 0); // Initialization vector.
const decipher = crypto.createDecipheriv(algorithm, key, iv);
// Encrypted using same algorithm, key and iv.
const encrypted =
'e5f79c5915c02171eec6b212d5520d44480993d7d622a7c4c2da32f6efda0ffa';
let decrypted = decipher.update(encrypted, 'hex', 'utf8');
decrypted += decipher.final('utf8');
console.log(decrypted);
// Prints: some clear text data
decipher.final([outputEncoding])#
outputEncoding
<string> The encoding of the return value.- Returns: <Buffer> | <string> Any remaining deciphered contents.
If
outputEncoding
is specified, a string is returned. If anoutputEncoding
is not provided, aBuffer
is returned.
Once the decipher.final()
method has been called, the Decipher
object can
no longer be used to decrypt data. Attempts to call decipher.final()
more
than once will result in an error being thrown.
decipher.setAAD(buffer[, options])#
buffer
<Buffer> | <TypedArray> | <DataView>-
options
<Object>stream.transform
optionsplaintextLength
<number>
- Returns: <Decipher> for method chaining.
When using an authenticated encryption mode (GCM
, CCM
and OCB
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 plaintext in bytes. See CCM mode.
The decipher.setAAD()
method must be called before decipher.update()
.
decipher.setAuthTag(buffer)#
buffer
<Buffer> | <TypedArray> | <DataView>- Returns: <Decipher> for method chaining.
When using an authenticated encryption mode (GCM
, CCM
and OCB
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.
Note that this Node.js version does not verify the length of GCM authentication tags. Such a check must be implemented by applications and is crucial to the authenticity of the encrypted data, otherwise, an attacker can use an arbitrarily short authentication tag to increase the chances of successfully passing authentication (up to 0.39%). It is highly recommended to associate one of the values 16, 15, 14, 13, 12, 8 or 4 bytes with each key, and to only permit authentication tags of that length, see NIST SP 800-38D.
The decipher.setAuthTag()
method must be called before
decipher.final()
.
decipher.setAutoPadding([autoPadding])#
autoPadding
<boolean> Default:true
- Returns: <Decipher> for method chaining.
When data has been encrypted without standard block padding, calling
decipher.setAutoPadding(false)
will disable automatic padding to prevent
decipher.final()
from checking for and removing padding.
Turning auto padding off will only work if the input data's length is a multiple of the ciphers block size.
The decipher.setAutoPadding()
method must be called before
decipher.final()
.
decipher.update(data[, inputEncoding][, outputencoding])#
data
<string> | <Buffer> | <TypedArray> | <DataView>inputEncoding
<string> The encoding of thedata
string.outputEncoding
<string> The encoding of the return value.- Returns: <Buffer> | <string>
Updates the decipher with data
. If the inputEncoding
argument is given,
the data
argument is a string using the specified encoding. If the inputEncoding
argument is not given, data
must be a Buffer
. If data
is a
Buffer
then inputEncoding
is ignored.
The outputEncoding
specifies the output format of the enciphered
data. If the outputEncoding
is specified, a string using the specified encoding is returned. If no
outputEncoding
is provided, a Buffer
is returned.
The decipher.update()
method can be called multiple times with new data until
decipher.final()
is called. Calling decipher.update()
after
decipher.final()
will result in an error being thrown.
Class: DiffieHellman#
The DiffieHellman
class is a utility for creating Diffie-Hellman key
exchanges.
Instances of the DiffieHellman
class can be created using the
crypto.createDiffieHellman()
function.
const crypto = require('crypto');
const assert = require('assert');
// Generate Alice's keys...
const alice = crypto.createDiffieHellman(2048);
const aliceKey = alice.generateKeys();
// Generate Bob's keys...
const bob = crypto.createDiffieHellman(alice.getPrime(), alice.getGenerator());
const bobKey = bob.generateKeys();
// Exchange and generate the secret...
const aliceSecret = alice.computeSecret(bobKey);
const bobSecret = bob.computeSecret(aliceKey);
// OK
assert.strictEqual(aliceSecret.toString('hex'), bobSecret.toString('hex'));
diffieHellman.computeSecret(otherPublicKey[, inputEncoding][, outputencoding])#
otherPublicKey
<string> | <Buffer> | <TypedArray> | <DataView>inputEncoding
<string> The encoding of anotherPublicKey
string.outputEncoding
<string> The encoding of the return value.- Returns: <Buffer> | <string>
Computes the shared secret using otherPublicKey
as the other
party's public key and returns the computed shared secret. The supplied
key is interpreted using the specified inputEncoding
, and secret is
encoded using specified outputEncoding
.
If the inputEncoding
is not
provided, otherPublicKey
is expected to be a Buffer
,
TypedArray
, or DataView
.
If outputEncoding
is given a string is returned; otherwise, a
Buffer
is returned.
diffieHellman.generateKeys(encoding)#
Generates private and public Diffie-Hellman key values, and returns
the public key in the specified encoding
. This key should be
transferred to the other party.
If encoding
is provided a string is returned; otherwise a
Buffer
is returned.
diffieHellman.getGenerator(encoding)#
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)#
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)#
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)#
Returns the Diffie-Hellman public key in the specified encoding
.
If encoding
is provided a
string is returned; otherwise a Buffer
is returned.
diffieHellman.setPrivateKey(privateKey[, encoding])#
privateKey
<string> | <Buffer> | <TypedArray> | <DataView>encoding
<string> The encoding of theprivateKey
string.
Sets the Diffie-Hellman private key. If the encoding
argument is provided,
privateKey
is expected
to be a string. If no encoding
is provided, privateKey
is expected
to be a Buffer
, TypedArray
, or DataView
.
diffieHellman.setPublicKey(publicKey[, encoding])#
publicKey
<string> | <Buffer> | <TypedArray> | <DataView>encoding
<string> The encoding of thepublicKey
string.
Sets the Diffie-Hellman public key. If the encoding
argument is provided,
publicKey
is expected
to be a string. If no encoding
is provided, publicKey
is expected
to be a Buffer
, TypedArray
, or DataView
.
diffieHellman.verifyError#
A bit field containing any warnings and/or errors resulting from a check
performed during initialization of the DiffieHellman
object.
The following values are valid for this property (as defined in constants
module):
DH_CHECK_P_NOT_SAFE_PRIME
DH_CHECK_P_NOT_PRIME
DH_UNABLE_TO_CHECK_GENERATOR
DH_NOT_SUITABLE_GENERATOR
Class: ECDH#
The ECDH
class is a utility for creating Elliptic Curve Diffie-Hellman (ECDH)
key exchanges.
Instances of the ECDH
class can be created using the
crypto.createECDH()
function.
const crypto = require('crypto');
const assert = require('assert');
// Generate Alice's keys...
const alice = crypto.createECDH('secp521r1');
const aliceKey = alice.generateKeys();
// Generate Bob's keys...
const bob = crypto.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
Class Method: ECDH.convertKey(key, curve[, inputEncoding[, outputEncoding[, format]]])#
key
<string> | <Buffer> | <TypedArray> | <DataView>curve
<string>inputEncoding
<string> The encoding of thekey
string.outputEncoding
<string> The encoding of the return value.format
<string> Default:'uncompressed'
- Returns: <Buffer> | <string>
Converts the EC Diffie-Hellman public key specified by key
and curve
to the
format specified by format
. The format
argument specifies point encoding
and can be 'compressed'
, 'uncompressed'
or 'hybrid'
. The supplied key is
interpreted using the specified inputEncoding
, and the returned key is encoded
using the specified outputEncoding
.
Use crypto.getCurves()
to obtain a list of available curve names.
On recent OpenSSL releases, openssl ecparam -list_curves
will also display
the name and description of each available elliptic curve.
If format
is not specified the point will be returned in 'uncompressed'
format.
If the inputEncoding
is not provided, key
is expected to be a Buffer
,
TypedArray
, or DataView
.
Example (uncompressing a key):
const { createECDH, ECDH } = require('crypto');
const ecdh = createECDH('secp256k1');
ecdh.generateKeys();
const compressedKey = ecdh.getPublicKey('hex', 'compressed');
const uncompressedKey = ECDH.convertKey(compressedKey,
'secp256k1',
'hex',
'hex',
'uncompressed');
// the converted key and the uncompressed public key should be the same
console.log(uncompressedKey === ecdh.getPublicKey('hex'));
ecdh.computeSecret(otherPublicKey[, inputEncoding][, outputencoding])#
otherPublicKey
<string> | <Buffer> | <TypedArray> | <DataView>inputEncoding
<string> The encoding of theotherPublicKey
string.outputEncoding
<string> The encoding of the return value.- Returns: <Buffer> | <string>
Computes the shared secret using otherPublicKey
as the other
party's public key and returns the computed shared secret. The supplied
key is interpreted using specified inputEncoding
, and the returned secret
is encoded using the specified outputEncoding
.
If the inputEncoding
is not
provided, otherPublicKey
is expected to be a Buffer
, TypedArray
, or
DataView
.
If outputEncoding
is given a string will be returned; otherwise a
Buffer
is returned.
ecdh.computeSecret
will throw an
ERR_CRYPTO_ECDH_INVALID_PUBLIC_KEY
error when otherPublicKey
lies outside of the elliptic curve. Since otherPublicKey
is
usually supplied from a remote user over an insecure network,
its recommended for developers to handle this exception accordingly.
ecdh.generateKeys([encoding[, format]])#
encoding
<string> The encoding of the return value.format
<string> Default:'uncompressed'
- Returns: <Buffer> | <string>
Generates private and public EC Diffie-Hellman key values, and returns
the public key in the specified format
and encoding
. This key should be
transferred to the other party.
The format
argument specifies point encoding and can be 'compressed'
or
'uncompressed'
. If format
is not specified, the point will be returned in
'uncompressed'
format.
If encoding
is provided a string is returned; otherwise a Buffer
is returned.
ecdh.getPrivateKey(encoding)#
encoding
<string> The encoding of the return value.- Returns: <Buffer> | <string> The EC Diffie-Hellman in the specified
encoding
.
If encoding
is specified, a string is returned; otherwise a Buffer
is
returned.
ecdh.getPublicKey([encoding][, format])#
encoding
<string> The encoding of the return value.format
<string> Default:'uncompressed'
- Returns: <Buffer> | <string> The EC Diffie-Hellman public key in the specified
encoding
andformat
.
The format
argument specifies point encoding and can be 'compressed'
or
'uncompressed'
. If format
is not specified the point will be returned in
'uncompressed'
format.
If encoding
is specified, a string is returned; otherwise a Buffer
is
returned.
ecdh.setPrivateKey(privateKey[, encoding])#
privateKey
<string> | <Buffer> | <TypedArray> | <DataView>encoding
<string> The encoding of theprivateKey
string.
Sets the EC Diffie-Hellman private key.
If encoding
is provided, privateKey
is expected
to be a string; otherwise privateKey
is expected to be a Buffer
,
TypedArray
, or DataView
.
If privateKey
is not valid for the curve specified when the ECDH
object was
created, an error is thrown. Upon setting the private key, the associated
public point (key) is also generated and set in the ECDH
object.
ecdh.setPublicKey(publicKey[, encoding])#
publicKey
<string> | <Buffer> | <TypedArray> | <DataView>encoding
<string> The encoding of thepublicKey
string.
Sets the EC Diffie-Hellman public key.
If encoding
is provided publicKey
is expected to
be a string; otherwise a Buffer
, TypedArray
, or DataView
is expected.
Note that 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 crypto = require('crypto');
const alice = crypto.createECDH('secp256k1');
const bob = crypto.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(
crypto.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#
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()
andhash.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 crypto = require('crypto');
const hash = crypto.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:
const crypto = require('crypto');
const fs = require('fs');
const hash = crypto.createHash('sha256');
const input = fs.createReadStream('test.js');
input.pipe(hash).pipe(process.stdout);
Example: Using the hash.update()
and hash.digest()
methods:
const crypto = require('crypto');
const hash = crypto.createHash('sha256');
hash.update('some data to hash');
console.log(hash.digest('hex'));
// Prints:
// 6a2da20943931e9834fc12cfe5bb47bbd9ae43489a30726962b576f4e3993e50
hash.digest(encoding)#
Calculates the digest of all of the data passed to be hashed (using the
hash.update()
method).
If encoding
is provided a string will be returned; otherwise
a Buffer
is returned.
The Hash
object can not be used again after hash.digest()
method has been
called. Multiple calls will cause an error to be thrown.
hash.update(data[, inputEncoding])#
data
<string> | <Buffer> | <TypedArray> | <DataView>inputEncoding
<string> The encoding of thedata
string.
Updates the hash content with the given data
, the encoding of which
is given in inputEncoding
.
If encoding
is not provided, and the data
is a string, an
encoding of 'utf8'
is enforced. If data
is a Buffer
, TypedArray
, or
DataView
, then inputEncoding
is ignored.
This can be called many times with new data as it is streamed.
Class: Hmac#
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()
andhmac.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 crypto = require('crypto');
const hmac = crypto.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:
const crypto = require('crypto');
const fs = require('fs');
const hmac = crypto.createHmac('sha256', 'a secret');
const input = fs.createReadStream('test.js');
input.pipe(hmac).pipe(process.stdout);
Example: Using the hmac.update()
and hmac.digest()
methods:
const crypto = require('crypto');
const hmac = crypto.createHmac('sha256', 'a secret');
hmac.update('some data to hash');
console.log(hmac.digest('hex'));
// Prints:
// 7fd04df92f636fd450bc841c9418e5825c17f33ad9c87c518115a45971f7f77e
hmac.digest(encoding)#
Calculates the HMAC digest of all of the data passed using hmac.update()
.
If encoding
is
provided a string is returned; otherwise a Buffer
is returned;
The Hmac
object can not be used again after hmac.digest()
has been
called. Multiple calls to hmac.digest()
will result in an error being thrown.
hmac.update(data[, inputEncoding])#
data
<string> | <Buffer> | <TypedArray> | <DataView>inputEncoding
<string> The encoding of thedata
string.
Updates the Hmac
content with the given data
, the encoding of which
is given in inputEncoding
.
If encoding
is not provided, and the data
is a string, an
encoding of 'utf8'
is enforced. If data
is a Buffer
, TypedArray
, or
DataView
, then inputEncoding
is ignored.
This can be called many times with new data as it is streamed.
Class: Sign#
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()
andsign.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
objects as streams:
const crypto = require('crypto');
const sign = crypto.createSign('SHA256');
sign.write('some data to sign');
sign.end();
const privateKey = getPrivateKeySomehow();
console.log(sign.sign(privateKey, 'hex'));
// Prints: the calculated signature using the specified private key and
// SHA-256. For RSA keys, the algorithm is RSASSA-PKCS1-v1_5 (see padding
// parameter below for RSASSA-PSS). For EC keys, the algorithm is ECDSA.
Example: Using the sign.update()
and sign.sign()
methods:
const crypto = require('crypto');
const sign = crypto.createSign('SHA256');
sign.update('some data to sign');
const privateKey = getPrivateKeySomehow();
console.log(sign.sign(privateKey, 'hex'));
// Prints: the calculated signature
In some cases, a Sign
instance can also be created by passing in a signature
algorithm name, such as 'RSA-SHA256'. This will use the corresponding digest
algorithm. This does not work for all signature algorithms, such as
'ecdsa-with-SHA256'. Use digest names instead.
Example: signing using legacy signature algorithm name
const crypto = require('crypto');
const sign = crypto.createSign('RSA-SHA256');
sign.update('some data to sign');
const privateKey = getPrivateKeySomehow();
console.log(sign.sign(privateKey, 'hex'));
// Prints: the calculated signature
sign.sign(privateKey[, outputEncoding])#
Calculates the signature on all the data passed through using either
sign.update()
or sign.write()
.
The privateKey
argument can be an object or a string. If privateKey
is a
string, it is treated as a raw key with no passphrase. If privateKey
is an
object, it must contain one or more of the following properties:
-
key
: <string> - PEM encoded private key (required) -
passphrase
: <string> - passphrase for the private key -
padding
: <integer> - Optional padding value for RSA, one of the following:crypto.constants.RSA_PKCS1_PADDING
(default)crypto.constants.RSA_PKCS1_PSS_PADDING
Note that
RSA_PKCS1_PSS_PADDING
will use MGF1 with the same hash function used to sign the message as specified in section 3.1 of RFC 4055. -
saltLength
: <integer> - salt length for when padding isRSA_PKCS1_PSS_PADDING
. The special valuecrypto.constants.RSA_PSS_SALTLEN_DIGEST
sets the salt length to the digest size,crypto.constants.RSA_PSS_SALTLEN_MAX_SIGN
(default) sets it to the maximum permissible value.
If outputEncoding
is provided a string is returned; otherwise a Buffer
is returned.
The Sign
object can not be again used after sign.sign()
method has been
called. Multiple calls to sign.sign()
will result in an error being thrown.
sign.update(data[, inputEncoding])#
data
<string> | <Buffer> | <TypedArray> | <DataView>inputEncoding
<string> The encoding of thedata
string.
Updates the Sign
content with the given data
, the encoding of which
is given in inputEncoding
.
If encoding
is not provided, and the data
is a string, an
encoding of 'utf8'
is enforced. If data
is a Buffer
, TypedArray
, or
DataView
, then inputEncoding
is ignored.
This can be called many times with new data as it is streamed.
Class: Verify#
The Verify
class is a utility for verifying signatures. It can be used in one
of two ways:
- As a writable stream where written data is used to validate against the supplied signature, or
- Using the
verify.update()
andverify.verify()
methods to verify the signature.
The crypto.createVerify()
method is used to create Verify
instances.
Verify
objects are not to be created directly using the new
keyword.
Example: Using Verify
objects as streams:
const crypto = require('crypto');
const verify = crypto.createVerify('SHA256');
verify.write('some data to sign');
verify.end();
const publicKey = getPublicKeySomehow();
const signature = getSignatureToVerify();
console.log(verify.verify(publicKey, signature));
// Prints: true or false
Example: Using the verify.update()
and verify.verify()
methods:
const crypto = require('crypto');
const verify = crypto.createVerify('SHA256');
verify.update('some data to sign');
const publicKey = getPublicKeySomehow();
const signature = getSignatureToVerify();
console.log(verify.verify(publicKey, signature));
// Prints: true or false
verify.update(data[, inputEncoding])#
data
<string> | <Buffer> | <TypedArray> | <DataView>inputEncoding
<string> The encoding of thedata
string.
Updates the Verify
content with the given data
, the encoding of which
is given in inputEncoding
.
If inputEncoding
is not provided, and the data
is a string, an
encoding of 'utf8'
is enforced. If data
is a Buffer
, TypedArray
, or
DataView
, then inputEncoding
is ignored.
This can be called many times with new data as it is streamed.
verify.verify(object, signature[, signatureEncoding])#
object
<string> | <Object>signature
<string> | <Buffer> | <TypedArray> | <DataView>signatureEncoding
<string> The encoding of thesignature
string.- Returns: <boolean>
true
orfalse
depending on the validity of the signature for the data and public key.
Verifies the provided data using the given object
and signature
.
The object
argument can be either a string containing a PEM encoded object,
which can be an RSA public key, a DSA public key, or an X.509 certificate,
or an object with one or more of the following properties:
-
key
: <string> - PEM encoded public key (required) -
padding
: <integer> - Optional padding value for RSA, one of the following:crypto.constants.RSA_PKCS1_PADDING
(default)crypto.constants.RSA_PKCS1_PSS_PADDING
Note that
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. -
saltLength
: <integer> - salt length for when padding isRSA_PKCS1_PSS_PADDING
. The special valuecrypto.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.
crypto
module methods and properties#
crypto.constants#
- Returns: <Object> An object containing commonly used constants for crypto and security related operations. The specific constants currently defined are described in Crypto Constants.
crypto.DEFAULT_ENCODING#
The default encoding to use for functions that can take either strings
or buffers. The default value is 'buffer'
, which makes methods
default to Buffer
objects.
The crypto.DEFAULT_ENCODING
mechanism is provided for backwards compatibility
with legacy programs that expect 'latin1'
to be the default encoding.
New applications should expect the default to be 'buffer'
.
This property is deprecated.
crypto.fips#
Property for checking and controlling whether a FIPS compliant crypto provider is currently in use. Setting to true requires a FIPS build of Node.js.
This property is deprecated. Please use crypto.setFips()
and
crypto.getFips()
instead.
crypto.createCipher(algorithm, password[, options])[src]#
crypto.createCipheriv()
instead.algorithm
<string>password
<string> | <Buffer> | <TypedArray> | <DataView>options
<Object>stream.transform
options- Returns: <Cipher>
Creates and returns a Cipher
object that uses the given algorithm
and
password
.
The options
argument controls stream behavior and is optional except when a
cipher in CCM or OCB mode is used (e.g. 'aes-128-ccm'
). In that case, the
authTagLength
option is required and specifies the length of the
authentication tag in bytes, see CCM mode. In GCM mode, the authTagLength
option is not required but can be used to set the length of the authentication
tag that will be returned by getAuthTag()
and defaults to 16 bytes.
The algorithm
is dependent on OpenSSL, examples are 'aes192'
, etc. On
recent OpenSSL releases, openssl list -cipher-algorithms
(openssl list-cipher-algorithms
for older versions of OpenSSL) will
display the available cipher algorithms.
The password
is used to derive the cipher key and initialization vector (IV).
The value must be either a 'latin1'
encoded string, a Buffer
, a
TypedArray
, or a DataView
.
The implementation of crypto.createCipher()
derives keys using the OpenSSL
function EVP_BytesToKey
with the digest algorithm set to MD5, one
iteration, and no salt. The lack of salt allows dictionary attacks as the same
password always creates the same key. The low iteration count and
non-cryptographically secure hash algorithm allow passwords to be tested very
rapidly.
In line with OpenSSL's recommendation to use a more modern algorithm instead of
EVP_BytesToKey
it is recommended that developers derive a key and IV on
their own using crypto.scrypt()
and to use crypto.createCipheriv()
to create the Cipher
object. Users should not use ciphers with counter mode
(e.g. CTR, GCM, or CCM) in crypto.createCipher()
. A warning is emitted when
they are used in order to avoid the risk of IV reuse that causes
vulnerabilities. For the case when IV is reused in GCM, see Nonce-Disrespecting
Adversaries for details.
crypto.createCipheriv(algorithm, key, iv[, options])[src]#
algorithm
<string>key
<string> | <Buffer> | <TypedArray> | <DataView>iv
<string> | <Buffer> | <TypedArray> | <DataView>options
<Object>stream.transform
options- Returns: <Cipher>
Creates and returns a Cipher
object, with the given algorithm
, key
and
initialization vector (iv
).
The options
argument controls stream behavior and is optional except when a
cipher in CCM or OCB mode is used (e.g. 'aes-128-ccm'
). In that case, the
authTagLength
option is required and specifies the length of the
authentication tag in bytes, see CCM mode. In GCM mode, the authTagLength
option is not required but can be used to set the length of the authentication
tag that will be returned by getAuthTag()
and defaults to 16 bytes.
The algorithm
is dependent on OpenSSL, examples are 'aes192'
, etc. On
recent OpenSSL releases, openssl list -cipher-algorithms
(openssl list-cipher-algorithms
for older versions of OpenSSL) will
display the available cipher algorithms.
The key
is the raw key used by the algorithm
and iv
is an
initialization vector. Both arguments must be 'utf8'
encoded strings,
Buffers, TypedArray
, or DataView
s. If the cipher does not need
an initialization vector, iv
may be null
.
Initialization vectors should be unpredictable and unique; ideally, they will be cryptographically random. They do not have to be secret: IVs are typically just added to ciphertext messages unencrypted. It may sound contradictory that something has to be unpredictable and unique, but does not have to be secret; it is important to remember that an attacker must not be able to predict ahead of time what a given IV will be.
crypto.createCredentials(details)#
tls.createSecureContext()
instead.details
<Object> Identical totls.createSecureContext()
.- Returns: <tls.SecureContext>
The crypto.createCredentials()
method is a deprecated function for creating
and returning a tls.SecureContext
. It should not be used. Replace it with
tls.createSecureContext()
which has the exact same arguments and return
value.
Returns a tls.SecureContext
, as-if tls.createSecureContext()
had been
called.
crypto.createDecipher(algorithm, password[, options])[src]#
crypto.createDecipheriv()
instead.algorithm
<string>password
<string> | <Buffer> | <TypedArray> | <DataView>options
<Object>stream.transform
options- Returns: <Decipher>
Creates and returns a Decipher
object that uses the given algorithm
and
password
(key).
The options
argument controls stream behavior and is optional except when a
cipher in CCM or OCB mode is used (e.g. 'aes-128-ccm'
). In that case, the
authTagLength
option is required and specifies the length of the
authentication tag in bytes, see CCM mode.
The implementation of crypto.createDecipher()
derives keys using the OpenSSL
function EVP_BytesToKey
with the digest algorithm set to MD5, one
iteration, and no salt. The lack of salt allows dictionary attacks as the same
password always creates the same key. The low iteration count and
non-cryptographically secure hash algorithm allow passwords to be tested very
rapidly.
In line with OpenSSL's recommendation to use a more modern algorithm instead of
EVP_BytesToKey
it is recommended that developers derive a key and IV on
their own using crypto.scrypt()
and to use crypto.createDecipheriv()
to create the Decipher
object.
crypto.createDecipheriv(algorithm, key, iv[, options])[src]#
algorithm
<string>key
<string> | <Buffer> | <TypedArray> | <DataView>iv
<string> | <Buffer> | <TypedArray> | <DataView>options
<Object>stream.transform
options- Returns: <Decipher>
Creates and returns a Decipher
object that uses the given algorithm
, key
and initialization vector (iv
).
The options
argument controls stream behavior and is optional except when a
cipher in CCM or OCB mode is used (e.g. 'aes-128-ccm'
). In that case, the
authTagLength
option is required and specifies the length of the
authentication tag in bytes, see CCM mode. In GCM mode, the authTagLength
option is not required but can be used to restrict accepted authentication tags
to those with the specified length.
The algorithm
is dependent on OpenSSL, examples are 'aes192'
, etc. On
recent OpenSSL releases, openssl list -cipher-algorithms
(openssl list-cipher-algorithms
for older versions of OpenSSL) will
display the available cipher algorithms.
The key
is the raw key used by the algorithm
and iv
is an
initialization vector. Both arguments must be 'utf8'
encoded strings,
Buffers, TypedArray
, or DataView
s. If the cipher does not need
an initialization vector, iv
may be null
.
Initialization vectors should be unpredictable and unique; ideally, they will be cryptographically random. They do not have to be secret: IVs are typically just added to ciphertext messages unencrypted. It may sound contradictory that something has to be unpredictable and unique, but does not have to be secret; it is important to remember that an attacker must not be able to predict ahead of time what a given IV will be.
crypto.createDiffieHellman(prime[, primeEncoding][, generator][, generatorEncoding])[src]#
prime
<string> | <Buffer> | <TypedArray> | <DataView>primeEncoding
<string> The encoding of theprime
string.generator
<number> | <string> | <Buffer> | <TypedArray> | <DataView> Default:2
generatorEncoding
<string> The encoding of thegenerator
string.- Returns: <DiffieHellman>
Creates a DiffieHellman
key exchange object using the supplied prime
and an
optional specific generator
.
The generator
argument can be a number, string, or Buffer
. If
generator
is not specified, the value 2
is used.
If primeEncoding
is specified, prime
is expected to be a string; otherwise
a Buffer
, TypedArray
, or DataView
is expected.
If generatorEncoding
is specified, generator
is expected to be a string;
otherwise a number, Buffer
, TypedArray
, or DataView
is expected.
crypto.createDiffieHellman(primeLength[, generator])[src]#
primeLength
<number>generator
<number> | <string> | <Buffer> | <TypedArray> | <DataView> Default:2
- Returns: <DiffieHellman>
Creates a DiffieHellman
key exchange object and generates a prime of
primeLength
bits using an optional specific numeric generator
.
If generator
is not specified, the value 2
is used.
crypto.createECDH(curveName)[src]#
Creates an Elliptic Curve Diffie-Hellman (ECDH
) key exchange object using a
predefined curve specified by the curveName
string. Use
crypto.getCurves()
to obtain a list of available curve names. On recent
OpenSSL releases, openssl ecparam -list_curves
will also display the name
and description of each available elliptic curve.
crypto.createHash(algorithm[, options])[src]#
algorithm
<string>options
<Object>stream.transform
options- Returns: <Hash>
Creates and returns a Hash
object that can be used to generate hash digests
using the given algorithm
. Optional options
argument controls stream
behavior.
The algorithm
is dependent on the available algorithms supported by the
version of OpenSSL on the platform. Examples are 'sha256'
, 'sha512'
, etc.
On recent releases of OpenSSL, openssl list -digest-algorithms
(openssl list-message-digest-algorithms
for older versions of OpenSSL) will
display the available digest algorithms.
Example: generating the sha256 sum of a file
const filename = process.argv[2];
const crypto = require('crypto');
const fs = require('fs');
const hash = crypto.createHash('sha256');
const input = fs.createReadStream(filename);
input.on('readable', () => {
// Only one element is going to be produced by the
// hash stream.
const data = input.read();
if (data)
hash.update(data);
else {
console.log(`${hash.digest('hex')} ${filename}`);
}
});
crypto.createHmac(algorithm, key[, options])[src]#
algorithm
<string>key
<string> | <Buffer> | <TypedArray> | <DataView>options
<Object>stream.transform
options- Returns: <Hmac>
Creates and returns an Hmac
object that uses the given algorithm
and key
.
Optional options
argument controls stream behavior.
The algorithm
is dependent on the available algorithms supported by the
version of OpenSSL on the platform. Examples are 'sha256'
, 'sha512'
, etc.
On recent releases of OpenSSL, openssl list -digest-algorithms
(openssl list-message-digest-algorithms
for older versions of OpenSSL) will
display the available digest algorithms.
The key
is the HMAC key used to generate the cryptographic HMAC hash.
Example: generating the sha256 HMAC of a file
const filename = process.argv[2];
const crypto = require('crypto');
const fs = require('fs');
const hmac = crypto.createHmac('sha256', 'a secret');
const input = fs.createReadStream(filename);
input.on('readable', () => {
// Only one element is going to be produced by the
// hash stream.
const data = input.read();
if (data)
hmac.update(data);
else {
console.log(`${hmac.digest('hex')} ${filename}`);
}
});
crypto.createSign(algorithm[, options])[src]#
algorithm
<string>options
<Object>stream.Writable
options- Returns: <Sign>
Creates and returns a Sign
object that uses the given algorithm
.
Use crypto.getHashes()
to obtain an array of names of the available
signing algorithms. Optional options
argument controls the
stream.Writable
behavior.
crypto.createVerify(algorithm[, options])[src]#
algorithm
<string>options
<Object>stream.Writable
options- Returns: <Verify>
Creates and returns a Verify
object that uses the given algorithm.
Use crypto.getHashes()
to obtain an array of names of the available
signing algorithms. Optional options
argument controls the
stream.Writable
behavior.
crypto.generateKeyPair(type, options, callback)#
type
: <string> Must be'rsa'
,'dsa'
or'ec'
.-
options
: <Object>modulusLength
: <number> Key size in bits (RSA, DSA).publicExponent
: <number> Public exponent (RSA). Default:0x10001
.divisorLength
: <number> Size ofq
in bits (DSA).namedCurve
: <string> Name of the curve to use (EC).-
publicKeyEncoding
: <Object> -
privateKeyEncoding
: <Object>type
: <string> Must be one of'pkcs1'
(RSA only),'pkcs8'
or'sec1'
(EC only).format
: <string> Must be'pem'
or'der'
.cipher
: <string> If specified, the private key will be encrypted with the givencipher
andpassphrase
using PKCS#5 v2.0 password based encryption.passphrase
: <string> The passphrase to use for encryption, seecipher
.
-
callback
: <Function>
Generates a new asymmetric key pair of the given type
. Only RSA, DSA and EC
are currently supported.
It is recommended to encode public keys as 'spki'
and private keys as
'pkcs8'
with encryption:
const { generateKeyPair } = require('crypto');
generateKeyPair('rsa', {
modulusLength: 4096,
publicKeyEncoding: {
type: 'spki',
format: 'pem'
},
privateKeyEncoding: {
type: 'pkcs8',
format: 'pem',
cipher: 'aes-256-cbc',
passphrase: 'top secret'
}
}, (err, publicKey, privateKey) => {
// Handle errors and use the generated key pair.
});
On completion, callback
will be called with err
set to undefined
and
publicKey
/ privateKey
representing the generated key pair. When PEM
encoding was selected, the result will be a string, otherwise it will be a
buffer containing the data encoded as DER. Note that Node.js itself does not
accept DER, it is supported for interoperability with other libraries such as
WebCrypto only.
If this method is invoked as its util.promisify()
ed version, it returns
a Promise
for an Object
with publicKey
and privateKey
properties.
crypto.generateKeyPairSync(type, options)#
type
: <string> Must be'rsa'
,'dsa'
or'ec'
.-
options
: <Object>modulusLength
: <number> Key size in bits (RSA, DSA).publicExponent
: <number> Public exponent (RSA). Default:0x10001
.divisorLength
: <number> Size ofq
in bits (DSA).namedCurve
: <string> Name of the curve to use (EC).-
publicKeyEncoding
: <Object> -
privateKeyEncoding
: <Object>type
: <string> Must be one of'pkcs1'
(RSA only),'pkcs8'
or'sec1'
(EC only).format
: <string> Must be'pem'
or'der'
.cipher
: <string> If specified, the private key will be encrypted with the givencipher
andpassphrase
using PKCS#5 v2.0 password based encryption.passphrase
: <string> The passphrase to use for encryption, seecipher
.
-
Returns: <Object>
Generates a new asymmetric key pair of the given type
. Only RSA, DSA and EC
are currently supported.
It is recommended to encode public keys as 'spki'
and private keys as
'pkcs8'
with encryption:
const { generateKeyPairSync } = require('crypto');
const { publicKey, privateKey } = generateKeyPairSync('rsa', {
modulusLength: 4096,
publicKeyEncoding: {
type: 'spki',
format: 'pem'
},
privateKeyEncoding: {
type: 'pkcs8',
format: 'pem',
cipher: 'aes-256-cbc',
passphrase: 'top secret'
}
});
The return value { publicKey, privateKey }
represents the generated key pair.
When PEM encoding was selected, the respective key will be a string, otherwise
it will be a buffer containing the data encoded as DER.
crypto.getCiphers()#
- Returns: <string[]> An array with the names of the supported cipher algorithms.
const ciphers = crypto.getCiphers();
console.log(ciphers); // ['aes-128-cbc', 'aes-128-ccm', ...]
crypto.getCurves()#
- Returns: <string[]> An array with the names of the supported elliptic curves.
const curves = crypto.getCurves();
console.log(curves); // ['Oakley-EC2N-3', 'Oakley-EC2N-4', ...]
crypto.getDiffieHellman(groupName)#
groupName
<string>- Returns: <DiffieHellman>
Creates a predefined DiffieHellman
key exchange object. The
supported groups are: 'modp1'
, 'modp2'
, 'modp5'
(defined in
RFC 2412, but see Caveats) and 'modp14'
, 'modp15'
,
'modp16'
, 'modp17'
, 'modp18'
(defined in RFC 3526). The
returned object mimics the interface of objects created by
crypto.createDiffieHellman()
, but will not allow changing
the keys (with diffieHellman.setPublicKey()
, for example). The
advantage of using this method is that the parties do not have to
generate nor exchange a group modulus beforehand, saving both processor
and communication time.
Example (obtaining a shared secret):
const crypto = require('crypto');
const alice = crypto.getDiffieHellman('modp14');
const bob = crypto.getDiffieHellman('modp14');
alice.generateKeys();
bob.generateKeys();
const aliceSecret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
const bobSecret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
/* aliceSecret and bobSecret should be the same */
console.log(aliceSecret === bobSecret);
crypto.getFips()#
- Returns: <boolean>
true
if and only if a FIPS compliant crypto provider is currently in use.
crypto.getHashes()#
- Returns: <string[]> An array of the names of the supported hash algorithms,
such as
'RSA-SHA256'
.
const hashes = crypto.getHashes();
console.log(hashes); // ['DSA', 'DSA-SHA', 'DSA-SHA1', ...]
crypto.pbkdf2(password, salt, iterations, keylen, digest, callback)#
password
<string> | <Buffer> | <TypedArray> | <DataView>salt
<string> | <Buffer> | <TypedArray> | <DataView>iterations
<number>keylen
<number>digest
<string>-
callback
<Function>
Provides an asynchronous Password-Based Key Derivation Function 2 (PBKDF2)
implementation. A selected HMAC digest algorithm specified by digest
is
applied to derive a key of the requested byte length (keylen
) from the
password
, salt
and iterations
.
The supplied callback
function is called with two arguments: err
and
derivedKey
. If an error occurs while deriving the key, err
will be set;
otherwise err
will be null
. By default, the successfully generated
derivedKey
will be passed to the callback as a Buffer
. An error will be
thrown if any of the input arguments specify invalid values or types.
If digest
is null
, 'sha1'
will be used. This behavior will be deprecated
in a future version of Node.js.
The iterations
argument must be a number set as high as possible. The
higher the number of iterations, the more secure the derived key will be,
but will take a longer amount of time to complete.
The salt
should be as unique as possible. It is recommended that a salt is
random and at least 16 bytes long. See NIST SP 800-132 for details.
const crypto = require('crypto');
crypto.pbkdf2('secret', 'salt', 100000, 64, 'sha512', (err, derivedKey) => {
if (err) throw err;
console.log(derivedKey.toString('hex')); // '3745e48...08d59ae'
});
The crypto.DEFAULT_ENCODING
property can be used to change the way the
derivedKey
is passed to the callback. This property, however, has been
deprecated and use should be avoided.
const crypto = require('crypto');
crypto.DEFAULT_ENCODING = 'hex';
crypto.pbkdf2('secret', 'salt', 100000, 512, 'sha512', (err, derivedKey) => {
if (err) throw err;
console.log(derivedKey); // '3745e48...aa39b34'
});
An array of supported digest functions can be retrieved using
crypto.getHashes()
.
Note that this API uses libuv's threadpool, which can have surprising and
negative performance implications for some applications, see the
UV_THREADPOOL_SIZE
documentation for more information.
crypto.pbkdf2Sync(password, salt, iterations, keylen, digest)#
password
<string> | <Buffer> | <TypedArray> | <DataView>salt
<string> | <Buffer> | <TypedArray> | <DataView>iterations
<number>keylen
<number>digest
<string>- Returns: <Buffer>
Provides a synchronous Password-Based Key Derivation Function 2 (PBKDF2)
implementation. A selected HMAC digest algorithm specified by digest
is
applied to derive a key of the requested byte length (keylen
) from the
password
, salt
and iterations
.
If an error occurs an Error
will be thrown, otherwise the derived key will be
returned as a Buffer
.
If digest
is null
, 'sha1'
will be used. This behavior will be deprecated
in a future version of Node.js.
The iterations
argument must be a number set as high as possible. The
higher the number of iterations, the more secure the derived key will be,
but will take a longer amount of time to complete.
The salt
should be as unique as possible. It is recommended that a salt is
random and at least 16 bytes long. See NIST SP 800-132 for details.
const crypto = require('crypto');
const key = crypto.pbkdf2Sync('secret', 'salt', 100000, 64, 'sha512');
console.log(key.toString('hex')); // '3745e48...08d59ae'
The crypto.DEFAULT_ENCODING
property may be used to change the way the
derivedKey
is returned. This property, however, is deprecated and use
should be avoided.
const crypto = require('crypto');
crypto.DEFAULT_ENCODING = 'hex';
const key = crypto.pbkdf2Sync('secret', 'salt', 100000, 512, 'sha512');
console.log(key); // '3745e48...aa39b34'
An array of supported digest functions can be retrieved using
crypto.getHashes()
.
crypto.privateDecrypt(privateKey, buffer)#
-
privateKey
<Object> | <string>key
<string> A PEM encoded private key.passphrase
<string> An optional passphrase for the private key.padding
<crypto.constants> An optional padding value defined incrypto.constants
, which may be:crypto.constants.RSA_NO_PADDING
,crypto.constants.RSA_PKCS1_PADDING
, orcrypto.constants.RSA_PKCS1_OAEP_PADDING
.
buffer
<Buffer> | <TypedArray> | <DataView>- Returns: <Buffer> A new
Buffer
with the decrypted content.
Decrypts buffer
with privateKey
. buffer
was previously encrypted using
the corresponding public key, for example using crypto.publicEncrypt()
.
privateKey
can be an object or a string. If privateKey
is a string, it is
treated as the key with no passphrase and will use RSA_PKCS1_OAEP_PADDING
.
crypto.privateEncrypt(privateKey, buffer)#
-
privateKey
<Object> | <string>key
<string> A PEM encoded private key.passphrase
<string> An optional passphrase for the private key.padding
<crypto.constants> An optional padding value defined incrypto.constants
, which may be:crypto.constants.RSA_NO_PADDING
orcrypto.constants.RSA_PKCS1_PADDING
.
buffer
<Buffer> | <TypedArray> | <DataView>- Returns: <Buffer> A new
Buffer
with the encrypted content.
Encrypts buffer
with privateKey
. The returned data can be decrypted using
the corresponding public key, for example using crypto.publicDecrypt()
.
privateKey
can be an object or a string. If privateKey
is a string, it is
treated as the key with no passphrase and will use RSA_PKCS1_PADDING
.
crypto.publicDecrypt(key, buffer)#
-
key
<string> A PEM encoded public or private key.passphrase
<string> An optional passphrase for the private key.padding
<crypto.constants> An optional padding value defined incrypto.constants
, which may be:crypto.constants.RSA_NO_PADDING
orcrypto.constants.RSA_PKCS1_PADDING
.
buffer
<Buffer> | <TypedArray> | <DataView>- Returns: <Buffer> A new
Buffer
with the decrypted content.
Decrypts buffer
with key
.buffer
was previously encrypted using
the corresponding private key, for example using crypto.privateEncrypt()
.
key
can be an object or a string. If key
is a string, it is treated as
the key with no passphrase and will use RSA_PKCS1_PADDING
.
Because RSA public keys can be derived from private keys, a private key may be passed instead of a public key.
crypto.publicEncrypt(key, buffer)#
-
key
<string> A PEM encoded public or private key.passphrase
<string> An optional passphrase for the private key.padding
<crypto.constants> An optional padding value defined incrypto.constants
, which may be:crypto.constants.RSA_NO_PADDING
,crypto.constants.RSA_PKCS1_PADDING
, orcrypto.constants.RSA_PKCS1_OAEP_PADDING
.
buffer
<Buffer> | <TypedArray> | <DataView>- Returns: <Buffer> A new
Buffer
with the encrypted content.
Encrypts the content of buffer
with key
and returns a new
Buffer
with encrypted content. The returned data can be decrypted using
the corresponding private key, for example using crypto.privateDecrypt()
.
key
can be an object or a string. If key
is a string, it is treated as
the key with no passphrase and will use RSA_PKCS1_OAEP_PADDING
.
Because RSA public keys can be derived from private keys, a private key may be passed instead of a public key.
crypto.randomBytes(size[, callback])#
size
<number>-
callback
<Function> - Returns: <Buffer> if the
callback
function is not provided.
Generates cryptographically strong pseudo-random data. The size
argument
is a number indicating the number of bytes to generate.
If a callback
function is provided, the bytes are generated asynchronously
and the callback
function is invoked with two arguments: err
and buf
.
If an error occurs, err
will be an Error
object; otherwise it is null
. The
buf
argument is a Buffer
containing the generated bytes.
// Asynchronous
const crypto = require('crypto');
crypto.randomBytes(256, (err, buf) => {
if (err) throw err;
console.log(`${buf.length} bytes of random data: ${buf.toString('hex')}`);
});
If the callback
function is not provided, the random bytes are generated
synchronously and returned as a Buffer
. An error will be thrown if
there is a problem generating the bytes.
// Synchronous
const buf = crypto.randomBytes(256);
console.log(
`${buf.length} bytes of random data: ${buf.toString('hex')}`);
The crypto.randomBytes()
method will not complete until there is
sufficient entropy available.
This should normally never take longer than a few milliseconds. The only time
when generating the random bytes may conceivably block for a longer period of
time is right after boot, when the whole system is still low on entropy.
Note that this API uses libuv's threadpool, which can have surprising and
negative performance implications for some applications, see the
UV_THREADPOOL_SIZE
documentation for more information.
The asynchronous version of crypto.randomBytes()
is carried out in a single
threadpool request. To minimize threadpool task length variation, partition
large randomBytes
requests when doing so as part of fulfilling a client
request.
crypto.randomFillSync(buffer[, offset][, size])#
buffer
<Buffer> | <TypedArray> | <DataView> Must be supplied.offset
<number> Default:0
size
<number> Default:buffer.length - offset
- Returns: <Buffer> | <TypedArray> | <DataView> The object passed as
buffer
argument.
Synchronous version of crypto.randomFill()
.
const buf = Buffer.alloc(10);
console.log(crypto.randomFillSync(buf).toString('hex'));
crypto.randomFillSync(buf, 5);
console.log(buf.toString('hex'));
// The above is equivalent to the following:
crypto.randomFillSync(buf, 5, 5);
console.log(buf.toString('hex'));
Any TypedArray
or DataView
instance may be passed as buffer
.
const a = new Uint32Array(10);
console.log(Buffer.from(crypto.randomFillSync(a).buffer,
a.byteOffset, a.byteLength).toString('hex'));
const b = new Float64Array(10);
console.log(Buffer.from(crypto.randomFillSync(b).buffer,
b.byteOffset, b.byteLength).toString('hex'));
const c = new DataView(new ArrayBuffer(10));
console.log(Buffer.from(crypto.randomFillSync(c).buffer,
c.byteOffset, c.byteLength).toString('hex'));
crypto.randomFill(buffer[, offset][, size], callback)#
buffer
<Buffer> | <TypedArray> | <DataView> Must be supplied.offset
<number> Default:0
size
<number> Default:buffer.length - offset
callback
<Function>function(err, buf) {}
.
This function is similar to crypto.randomBytes()
but requires the first
argument to be a Buffer
that will be filled. It also
requires that a callback is passed in.
If the callback
function is not provided, an error will be thrown.
const buf = Buffer.alloc(10);
crypto.randomFill(buf, (err, buf) => {
if (err) throw err;
console.log(buf.toString('hex'));
});
crypto.randomFill(buf, 5, (err, buf) => {
if (err) throw err;
console.log(buf.toString('hex'));
});
// The above is equivalent to the following:
crypto.randomFill(buf, 5, 5, (err, buf) => {
if (err) throw err;
console.log(buf.toString('hex'));
});
Any TypedArray
or DataView
instance may be passed as buffer
.
const a = new Uint32Array(10);
crypto.randomFill(a, (err, buf) => {
if (err) throw err;
console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
.toString('hex'));
});
const b = new Float64Array(10);
crypto.randomFill(b, (err, buf) => {
if (err) throw err;
console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
.toString('hex'));
});
const c = new DataView(new ArrayBuffer(10));
crypto.randomFill(c, (err, buf) => {
if (err) throw err;
console.log(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength)
.toString('hex'));
});
Note that this API uses libuv's threadpool, which can have surprising and
negative performance implications for some applications, see the
UV_THREADPOOL_SIZE
documentation for more information.
The asynchronous version of crypto.randomFill()
is carried out in a single
threadpool request. To minimize threadpool task length variation, partition
large randomFill
requests when doing so as part of fulfilling a client
request.
crypto.scrypt(password, salt, keylen[, options], callback)#
password
<string> | <Buffer> | <TypedArray> | <DataView>salt
<string> | <Buffer> | <TypedArray> | <DataView>keylen
<number>-
options
<Object>cost
<number> CPU/memory cost parameter. Must be a power of two greaterN
<number> CPU/memory cost parameter. Must be a power of two greater than one. Default:16384
.blockSize
<number> Block size parameter. Default:8
.parallelization
<number> Parallelization parameter. Default:1
.N
<number> Alias forcost
. Only one of both may be specified.r
<number> Alias forblockSize
. Only one of both may be specified.p
<number> Alias forparallelization
. Only one of both may be specified.maxmem
<number> Memory upper bound. It is an error when (approximately)128 * N * r > maxmem
. Default:32 * 1024 * 1024
.
-
callback
<Function>
Provides an asynchronous scrypt implementation. Scrypt is a password-based key derivation function that is designed to be expensive computationally and memory-wise in order to make brute-force attacks unrewarding.
The salt
should be as unique as possible. It is recommended that a salt is
random and at least 16 bytes long. See NIST SP 800-132 for details.
The callback
function is called with two arguments: err
and derivedKey
.
err
is an exception object when key derivation fails, otherwise err
is
null
. derivedKey
is passed to the callback as a Buffer
.
An exception is thrown when any of the input arguments specify invalid values or types.
const crypto = require('crypto');
// Using the factory defaults.
crypto.scrypt('secret', 'salt', 64, (err, derivedKey) => {
if (err) throw err;
console.log(derivedKey.toString('hex')); // '3745e48...08d59ae'
});
// Using a custom N parameter. Must be a power of two.
crypto.scrypt('secret', 'salt', 64, { N: 1024 }, (err, derivedKey) => {
if (err) throw err;
console.log(derivedKey.toString('hex')); // '3745e48...aa39b34'
});
crypto.scryptSync(password, salt, keylen[, options])#
password
<string> | <Buffer> | <TypedArray> | <DataView>salt
<string> | <Buffer> | <TypedArray> | <DataView>keylen
<number>-
options
<Object>cost
<number> CPU/memory cost parameter. Must be a power of two greaterN
<number> CPU/memory cost parameter. Must be a power of two greater than one. Default:16384
.blockSize
<number> Block size parameter. Default:8
.parallelization
<number> Parallelization parameter. Default:1
.N
<number> Alias forcost
. Only one of both may be specified.r
<number> Alias forblockSize
. Only one of both may be specified.p
<number> Alias forparallelization
. Only one of both may be specified.maxmem
<number> Memory upper bound. It is an error when (approximately)128 * N * r > maxmem
. Default:32 * 1024 * 1024
.
- Returns: <Buffer>
Provides a synchronous scrypt implementation. Scrypt is a password-based key derivation function that is designed to be expensive computationally and memory-wise in order to make brute-force attacks unrewarding.
The salt
should be as unique as possible. It is recommended that a salt is
random and at least 16 bytes long. See NIST SP 800-132 for details.
An exception is thrown when key derivation fails, otherwise the derived key is
returned as a Buffer
.
An exception is thrown when any of the input arguments specify invalid values or types.
const crypto = require('crypto');
// Using the factory defaults.
const key1 = crypto.scryptSync('secret', 'salt', 64);
console.log(key1.toString('hex')); // '3745e48...08d59ae'
// Using a custom N parameter. Must be a power of two.
const key2 = crypto.scryptSync('secret', 'salt', 64, { N: 1024 });
console.log(key2.toString('hex')); // '3745e48...aa39b34'
crypto.setEngine(engine[, flags])#
engine
<string>flags
<crypto.constants> Default:crypto.constants.ENGINE_METHOD_ALL
Load and set the engine
for some or all OpenSSL functions (selected by flags).
engine
could be either an id or a path to the engine's shared library.
The optional flags
argument uses ENGINE_METHOD_ALL
by default. The flags
is a bit field taking one of or a mix of the following flags (defined in
crypto.constants
):
crypto.constants.ENGINE_METHOD_RSA
crypto.constants.ENGINE_METHOD_DSA
crypto.constants.ENGINE_METHOD_DH
crypto.constants.ENGINE_METHOD_RAND
crypto.constants.ENGINE_METHOD_EC
crypto.constants.ENGINE_METHOD_CIPHERS
crypto.constants.ENGINE_METHOD_DIGESTS
crypto.constants.ENGINE_METHOD_PKEY_METHS
crypto.constants.ENGINE_METHOD_PKEY_ASN1_METHS
crypto.constants.ENGINE_METHOD_ALL
crypto.constants.ENGINE_METHOD_NONE
The flags below are deprecated in OpenSSL-1.1.0.
crypto.constants.ENGINE_METHOD_ECDH
crypto.constants.ENGINE_METHOD_ECDSA
crypto.constants.ENGINE_METHOD_STORE
crypto.setFips(bool)#
bool
<boolean>true
to enable FIPS mode.
Enables the FIPS compliant crypto provider in a FIPS-enabled Node.js build. Throws an error if FIPS mode is not available.
crypto.timingSafeEqual(a, b)#
a
<Buffer> | <TypedArray> | <DataView>b
<Buffer> | <TypedArray> | <DataView>- Returns: <boolean>
This function is based on a constant-time algorithm.
Returns true if a
is equal to b
, without leaking timing information that
would allow an attacker to guess one of the values. This is suitable for
comparing HMAC digests or secret values like authentication cookies or
capability urls.
a
and b
must both be Buffer
s, TypedArray
s, or DataView
s, and they
must have the same length.
Use of crypto.timingSafeEqual
does not guarantee that the surrounding code
is timing-safe. Care should be taken to ensure that the surrounding code does
not introduce timing vulnerabilities.
Notes#
Legacy Streams API (pre Node.js v0.10)#
The Crypto module was added to Node.js before there was the concept of a
unified Stream API, and before there were Buffer
objects for handling
binary data. As such, the many of the crypto
defined classes have methods not
typically found on other Node.js classes that implement the streams
API (e.g. update()
, final()
, or digest()
). Also, many methods accepted
and returned 'latin1'
encoded strings by default rather than Buffer
s. This
default was changed after Node.js v0.8 to use Buffer
objects by default
instead.
Recent ECDH Changes#
Usage of ECDH
with non-dynamically generated key pairs has been simplified.
Now, ecdh.setPrivateKey()
can be called with a preselected private key
and the associated public point (key) will be computed and stored in the object.
This allows code to only store and provide the private part of the EC key pair.
ecdh.setPrivateKey()
now also validates that the private key is valid for
the selected curve.
The ecdh.setPublicKey()
method is now deprecated as its inclusion in the
API is not useful. Either a previously stored private key should be set, which
automatically generates the associated public key, or ecdh.generateKeys()
should be called. The main drawback of using ecdh.setPublicKey()
is that
it can be used to put the ECDH key pair into an inconsistent state.
Support for weak or compromised algorithms#
The crypto
module still supports some algorithms which are already
compromised and are not currently recommended for use. The API also allows
the use of ciphers and hashes with a small key size that are considered to be
too weak for safe use.
Users should take full responsibility for selecting the crypto algorithm and key size according to their security requirements.
Based on the recommendations of NIST SP 800-131A:
- MD5 and SHA-1 are no longer acceptable where collision resistance is required such as digital signatures.
- The key used with RSA, DSA, and DH algorithms is recommended to have at least 2048 bits and that of the curve of ECDSA and ECDH at least 224 bits, to be safe to use for several years.
- The DH groups of
modp1
,modp2
andmodp5
have a key size smaller than 2048 bits and are not recommended.
See the reference for other recommendations and details.
CCM mode#
CCM is one of the supported AEAD algorithms. Applications which use this mode must adhere to certain restrictions when using the cipher API:
- The authentication tag length must be specified during cipher creation by
setting the
authTagLength
option and must be one of 4, 6, 8, 10, 12, 14 or 16 bytes. - The length of the initialization vector (nonce)
N
must be between 7 and 13 bytes (7 ≤ N ≤ 13
). - The length of the plaintext is limited to
2 ** (8 * (15 - N))
bytes. - When decrypting, the authentication tag must be set via
setAuthTag()
before specifying additional authenticated data or callingupdate()
. Otherwise, decryption will fail andfinal()
will throw an error in compliance with section 2.6 of RFC 3610. - Using stream methods such as
write(data)
,end(data)
orpipe()
in CCM mode might fail as CCM cannot handle more than one chunk of data per instance. - When passing additional authenticated data (AAD), the length of the actual
message in bytes must be passed to
setAAD()
via theplaintextLength
option. This is not necessary if no AAD is used. - As CCM processes the whole message at once,
update()
can only be called once. - Even though calling
update()
is sufficient to encrypt/decrypt the message, applications must callfinal()
to compute or verify the authentication tag.
const crypto = require('crypto');
const key = 'keykeykeykeykeykeykeykey';
const nonce = crypto.randomBytes(12);
const aad = Buffer.from('0123456789', 'hex');
const cipher = crypto.createCipheriv('aes-192-ccm', key, nonce, {
authTagLength: 16
});
const plaintext = 'Hello world';
cipher.setAAD(aad, {
plaintextLength: Buffer.byteLength(plaintext)
});
const ciphertext = cipher.update(plaintext, 'utf8');
cipher.final();
const tag = cipher.getAuthTag();
// Now transmit { ciphertext, nonce, tag }.
const decipher = crypto.createDecipheriv('aes-192-ccm', key, nonce, {
authTagLength: 16
});
decipher.setAuthTag(tag);
decipher.setAAD(aad, {
plaintextLength: ciphertext.length
});
const receivedPlaintext = decipher.update(ciphertext, null, 'utf8');
try {
decipher.final();
} catch (err) {
console.error('Authentication failed!');
}
console.log(receivedPlaintext);
Crypto Constants#
The following constants exported by crypto.constants
apply to various uses of
the crypto
, tls
, and https
modules and are generally specific to OpenSSL.
OpenSSL Options#
Constant | Description |
---|---|
SSL_OP_ALL |
Applies multiple bug workarounds within OpenSSL. See https://www.openssl.org/docs/man1.0.2/ssl/SSL_CTX_set_options.html for detail. |
SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION |
Allows legacy insecure renegotiation between OpenSSL and unpatched clients or servers. See https://www.openssl.org/docs/man1.0.2/ssl/SSL_CTX_set_options.html. |
SSL_OP_CIPHER_SERVER_PREFERENCE |
Attempts to use the server's preferences instead of the client's when selecting a cipher. Behavior depends on protocol version. See https://www.openssl.org/docs/man1.0.2/ssl/SSL_CTX_set_options.html. |
SSL_OP_CISCO_ANYCONNECT |
Instructs OpenSSL to use Cisco's "speshul" version of DTLS_BAD_VER. |
SSL_OP_COOKIE_EXCHANGE |
Instructs OpenSSL to turn on cookie exchange. |
SSL_OP_CRYPTOPRO_TLSEXT_BUG |
Instructs OpenSSL to add server-hello extension from an early version of the cryptopro draft. |
SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS |
Instructs OpenSSL to disable a SSL 3.0/TLS 1.0 vulnerability workaround added in OpenSSL 0.9.6d. |
SSL_OP_EPHEMERAL_RSA |
Instructs OpenSSL to always use the tmp_rsa key when performing RSA operations. |
SSL_OP_LEGACY_SERVER_CONNECT |
Allows initial connection to servers that do not support RI. |
SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER |
|
SSL_OP_MICROSOFT_SESS_ID_BUG |
|
SSL_OP_MSIE_SSLV2_RSA_PADDING |
Instructs OpenSSL to disable the workaround for a man-in-the-middle protocol-version vulnerability in the SSL 2.0 server implementation. |
SSL_OP_NETSCAPE_CA_DN_BUG |
|
SSL_OP_NETSCAPE_CHALLENGE_BUG |
|
SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG |
|
SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG |
|
SSL_OP_NO_COMPRESSION |
Instructs OpenSSL to disable support for SSL/TLS compression. |
SSL_OP_NO_QUERY_MTU |
|
SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION |
Instructs OpenSSL to always start a new session when performing renegotiation. |
SSL_OP_NO_SSLv2 |
Instructs OpenSSL to turn off SSL v2 |
SSL_OP_NO_SSLv3 |
Instructs OpenSSL to turn off SSL v3 |
SSL_OP_NO_TICKET |
Instructs OpenSSL to disable use of RFC4507bis tickets. |
SSL_OP_NO_TLSv1 |
Instructs OpenSSL to turn off TLS v1 |
SSL_OP_NO_TLSv1_1 |
Instructs OpenSSL to turn off TLS v1.1 |
SSL_OP_NO_TLSv1_2 |
Instructs OpenSSL to turn off TLS v1.2 |
SSL_OP_PKCS1_CHECK_1 |
|
SSL_OP_PKCS1_CHECK_2 |
|
SSL_OP_SINGLE_DH_USE |
Instructs OpenSSL to always create a new key when using temporary/ephemeral DH parameters. |
SSL_OP_SINGLE_ECDH_USE |
Instructs OpenSSL to always create a new key when using temporary/ephemeral ECDH parameters. |
SSL_OP_SSLEAY_080_CLIENT_DH_BUG |
|
SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG |
|
SSL_OP_TLS_BLOCK_PADDING_BUG |
|
SSL_OP_TLS_D5_BUG |
|
SSL_OP_TLS_ROLLBACK_BUG |
Instructs OpenSSL to disable version rollback attack detection. |
OpenSSL Engine Constants#
Constant | Description |
---|---|
ENGINE_METHOD_RSA |
Limit engine usage to RSA |
ENGINE_METHOD_DSA |
Limit engine usage to DSA |
ENGINE_METHOD_DH |
Limit engine usage to DH |
ENGINE_METHOD_RAND |
Limit engine usage to RAND |
ENGINE_METHOD_EC |
Limit engine usage to EC |
ENGINE_METHOD_CIPHERS |
Limit engine usage to CIPHERS |
ENGINE_METHOD_DIGESTS |
Limit engine usage to DIGESTS |
ENGINE_METHOD_PKEY_METHS |
Limit engine usage to PKEY_METHDS |
ENGINE_METHOD_PKEY_ASN1_METHS |
Limit engine usage to PKEY_ASN1_METHS |
ENGINE_METHOD_ALL |
|
ENGINE_METHOD_NONE |
Other OpenSSL Constants#
Constant | Description |
---|---|
DH_CHECK_P_NOT_SAFE_PRIME |
|
DH_CHECK_P_NOT_PRIME |
|
DH_UNABLE_TO_CHECK_GENERATOR |
|
DH_NOT_SUITABLE_GENERATOR |
|
ALPN_ENABLED |
|
RSA_PKCS1_PADDING |
|
RSA_SSLV23_PADDING |
|
RSA_NO_PADDING |
|
RSA_PKCS1_OAEP_PADDING |
|
RSA_X931_PADDING |
|
RSA_PKCS1_PSS_PADDING |
|
RSA_PSS_SALTLEN_DIGEST |
Sets the salt length for RSA_PKCS1_PSS_PADDING to the
digest size when signing or verifying. |
RSA_PSS_SALTLEN_MAX_SIGN |
Sets the salt length for RSA_PKCS1_PSS_PADDING to the
maximum permissible value when signing data. |
RSA_PSS_SALTLEN_AUTO |
Causes the salt length for RSA_PKCS1_PSS_PADDING to be
determined automatically when verifying a signature. |
POINT_CONVERSION_COMPRESSED |
|
POINT_CONVERSION_UNCOMPRESSED |
|
POINT_CONVERSION_HYBRID |
Node.js Crypto Constants#
Constant | Description |
---|---|
defaultCoreCipherList |
Specifies the built-in default cipher list used by Node.js. |
defaultCipherList |
Specifies the active default cipher list used by the current Node.js process. |