# Crypto
- Stability: 2 - Unstable; API changes are being discussed for
- future versions. Breaking changes will be minimized. See below.
+ Stability: 2 - Stable
+
+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.
-The crypto module offers a way of encapsulating secure credentials to be
-used as part of a secure HTTPS net or http connection.
+```js
+const crypto = require('crypto');
-It also offers a set of wrappers for OpenSSL's hash, hmac, cipher,
-decipher, sign and verify methods.
+const secret = 'abcdefg';
+const hash = crypto.createHmac('sha256', secret)
+ .update('I love cupcakes')
+ .digest('hex');
+console.log(hash);
+ // Prints:
+ // c0fa1bc00531bd78ef38c628449c5102aeabd49b5dc3a2a516ea6ea959d6658e
+```
+## Class: Certificate
-## crypto.setEngine(engine, [flags])
+SPKAC is a Certificate Signing Request mechanism originally implemented by
+Netscape and now specified formally as part of [HTML5's `keygen` element][].
-Load and set engine for some/all OpenSSL functions (selected by flags).
+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.
-`engine` could be either an id or a path to the to the engine's shared library.
+### new crypto.Certificate()
-`flags` is optional and has `ENGINE_METHOD_ALL` value by default. It could take
-one of or mix of following flags (defined in `constants` module):
+Instances of the `Certificate` class can be created using the `new` keyword
+or by calling `crypto.Certificate()` as a function:
-* `ENGINE_METHOD_RSA`
-* `ENGINE_METHOD_DSA`
-* `ENGINE_METHOD_DH`
-* `ENGINE_METHOD_RAND`
-* `ENGINE_METHOD_ECDH`
-* `ENGINE_METHOD_ECDSA`
-* `ENGINE_METHOD_CIPHERS`
-* `ENGINE_METHOD_DIGESTS`
-* `ENGINE_METHOD_STORE`
-* `ENGINE_METHOD_PKEY_METH`
-* `ENGINE_METHOD_PKEY_ASN1_METH`
-* `ENGINE_METHOD_ALL`
-* `ENGINE_METHOD_NONE`
+```js
+const crypto = require('crypto');
+const cert1 = new crypto.Certificate();
+const cert2 = crypto.Certificate();
+```
-## crypto.getCiphers()
+### certificate.exportChallenge(spkac)
-Returns an array with the names of the supported ciphers.
+The `spkac` data structure includes a public key and a challenge. The
+`certificate.exportChallenge()` returns the challenge component in the
+form of a Node.js [`Buffer`][]. The `spkac` argument can be either a string
+or a [`Buffer`][].
-Example:
+```js
+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
+```
- var ciphers = crypto.getCiphers();
- console.log(ciphers); // ['AES-128-CBC', 'AES-128-CBC-HMAC-SHA1', ...]
+### certificate.exportPublicKey(spkac)
+The `spkac` data structure includes a public key and a challenge. The
+`certificate.exportPublicKey()` returns the public key component in the
+form of a Node.js [`Buffer`][]. The `spkac` argument can be either a string
+or a [`Buffer`][].
-## crypto.getHashes()
+```js
+const cert = require('crypto').Certificate();
+const spkac = getSpkacSomehow();
+const publicKey = cert.exportPublicKey(spkac);
+console.log(publicKey);
+ // Prints the public key as <Buffer ...>
+```
-Returns an array with the names of the supported hash algorithms.
+### certificate.verifySpkac(spkac)
-Example:
+Returns `true` if the given `spkac` data structure is valid, `false` otherwise.
+The `spkac` argument must be a Node.js [`Buffer`][].
- var hashes = crypto.getHashes();
- console.log(hashes); // ['sha', 'sha1', 'sha1WithRSAEncryption', ...]
+```js
+const cert = require('crypto').Certificate();
+const spkac = getSpkacSomehow();
+console.log(cert.verifySpkac(new Buffer(spkac)));
+ // Prints true or false
+```
+## Class: Cipher
-## crypto.createCredentials(details)
+Instances of the `Cipher` class are used to encrypt data. The class can be
+used in one of two ways:
-Creates a credentials object, with the optional details being a
-dictionary with keys:
+- As a [stream][] that is both readable and writable, where plain unencrypted
+ data is written to produce encrypted data on the readable side, or
+- Using the [`cipher.update()`][] and [`cipher.final()`][] methods to produce
+ the encrypted data.
-* `pfx` : A string or buffer holding the PFX or PKCS12 encoded private
- key, certificate and CA certificates
-* `key` : A string holding the PEM encoded private key
-* `passphrase` : A string of passphrase for the private key or pfx
-* `cert` : A string holding the PEM encoded certificate
-* `ca` : Either a string or list of strings of PEM encoded CA
- certificates to trust.
-* `crl` : Either a string or list of strings of PEM encoded CRLs
- (Certificate Revocation List)
-* `ciphers`: A string describing the ciphers to use or exclude.
- Consult
- <http://www.openssl.org/docs/apps/ciphers.html#CIPHER_LIST_FORMAT>
- for details on the format.
+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.
-If no 'ca' details are given, then node.js will use the default
-publicly trusted list of CAs as given in
-<http://mxr.mozilla.org/mozilla/source/security/nss/lib/ckfw/builtins/certdata.txt>.
+Example: Using `Cipher` objects as streams:
+```js
+const crypto = require('crypto');
+const cipher = crypto.createCipher('aes192', 'a password');
-## crypto.createHash(algorithm)
+var encrypted = '';
+cipher.on('readable', () => {
+ var data = cipher.read();
+ if (data)
+ encrypted += data.toString('hex');
+});
+cipher.on('end', () => {
+ console.log(encrypted);
+ // Prints: ca981be48e90867604588e75d04feabb63cc007a8f8ad89b10616ed84d815504
+});
-Creates and returns a hash object, a cryptographic hash with the given
-algorithm which can be used to generate hash digests.
+cipher.write('some clear text data');
+cipher.end();
+```
-`algorithm` is dependent on the available algorithms supported by the
-version of OpenSSL on the platform. Examples are `'sha1'`, `'md5'`,
-`'sha256'`, `'sha512'`, etc. On recent releases, `openssl
-list-message-digest-algorithms` will display the available digest
-algorithms.
+Example: Using `Cipher` and piped streams:
-Example: this program that takes the sha1 sum of a file
+```js
+const crypto = require('crypto');
+const fs = require('fs');
+const cipher = crypto.createCipher('aes192', 'a password');
- var filename = process.argv[2];
- var crypto = require('crypto');
- var fs = require('fs');
+const input = fs.createReadStream('test.js');
+const output = fs.createWriteStream('test.enc');
- var shasum = crypto.createHash('sha1');
+input.pipe(cipher).pipe(output);
+```
- var s = fs.ReadStream(filename);
- s.on('data', function(d) {
- shasum.update(d);
- });
+Example: Using the [`cipher.update()`][] and [`cipher.final()`][] methods:
- s.on('end', function() {
- var d = shasum.digest('hex');
- console.log(d + ' ' + filename);
- });
+```js
+const crypto = require('crypto');
+const cipher = crypto.createCipher('aes192', 'a password');
-## Class: Hash
+var encrypted = cipher.update('some clear text data', 'utf8', 'hex');
+encrypted += cipher.final('hex');
+console.log(encrypted);
+ // Prints: ca981be48e90867604588e75d04feabb63cc007a8f8ad89b10616ed84d815504
+```
-The class for creating hash digests of data.
+### cipher.final([output_encoding])
-It is a [stream](stream.html) that is both readable and writable. The
-written data is used to compute the hash. Once the writable side of
-the stream is ended, use the `read()` method to get the computed hash
-digest. The legacy `update` and `digest` methods are also supported.
+Returns any remaining enciphered contents. If `output_encoding`
+parameter is one of `'binary'`, `'base64'` or `'hex'`, a string is returned.
+If an `output_encoding` is not provided, a [`Buffer`][] is returned.
-Returned by `crypto.createHash`.
+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.
-### hash.update(data, [input_encoding])
+### cipher.setAAD(buffer)
-Updates the hash content with the given `data`, the encoding of which
-is given in `input_encoding` and can be `'utf8'`, `'ascii'` or
-`'binary'`. If no encoding is provided and the input is a string an
-encoding of `'binary'` is enforced. If `data` is a `Buffer` then
-`input_encoding` is ignored.
+When using an authenticated encryption mode (only `GCM` is currently
+supported), the `cipher.setAAD()` method sets the value used for the
+_additional authenticated data_ (AAD) input parameter.
-This can be called many times with new data as it is streamed.
+### cipher.getAuthTag()
-### hash.digest([encoding])
+When using an authenticated encryption mode (only `GCM` is currently
+supported), the `cipher.getAuthTag()` method returns a [`Buffer`][] containing
+the _authentication tag_ that has been computed from the given data.
-Calculates the digest of all of the passed data to be hashed. The
-`encoding` can be `'hex'`, `'binary'` or `'base64'`. If no encoding
-is provided, then a buffer is returned.
+The `cipher.getAuthTag()` method should only be called after encryption has
+been completed using the [`cipher.final()`][] method.
-Note: `hash` object can not be used after `digest()` method has been
-called.
+### cipher.setAutoPadding(auto_padding=true)
+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)`.
-## crypto.createHmac(algorithm, key)
+When `auto_padding` 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.
-Creates and returns a hmac object, a cryptographic hmac with the given
-algorithm and key.
+The `cipher.setAutoPadding()` method must be called before [`cipher.final()`][].
-It is a [stream](stream.html) that is both readable and writable. The
-written data is used to compute the hmac. Once the writable side of
-the stream is ended, use the `read()` method to get the computed
-digest. The legacy `update` and `digest` methods are also supported.
+### cipher.update(data[, input_encoding][, output_encoding])
-`algorithm` is dependent on the available algorithms supported by
-OpenSSL - see createHash above. `key` is the hmac key to be used.
+Updates the cipher with `data`. If the `input_encoding` argument is given,
+it's value must be one of `'utf8'`, `'ascii'`, or `'binary'` and the `data`
+argument is a string using the specified encoding. If the `input_encoding`
+argument is not given, `data` must be a [`Buffer`][]. If `data` is a
+[`Buffer`][] then `input_encoding` is ignored.
-## Class: Hmac
+The `output_encoding` specifies the output format of the enciphered
+data, and can be `'binary'`, `'base64'` or `'hex'`. If the `output_encoding`
+is specified, a string using the specified encoding is returned. If no
+`output_encoding` is provided, a [`Buffer`][] is returned.
-Class for creating cryptographic hmac content.
+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.
-Returned by `crypto.createHmac`.
+## Class: Decipher
-### hmac.update(data)
+Instances of the `Decipher` class are used to decrypt data. The class can be
+used in one of two ways:
-Update the hmac content with the given `data`. This can be called
-many times with new data as it is streamed.
+- As a [stream][] that is both readable and writable, where plain encrypted
+ data is written to produce unencrypted data on the readable side, or
+- Using the [`decipher.update()`][] and [`decipher.final()`][] methods to
+ produce the unencrypted data.
-### hmac.digest([encoding])
+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.
-Calculates the digest of all of the passed data to the hmac. The
-`encoding` can be `'hex'`, `'binary'` or `'base64'`. If no encoding
-is provided, then a buffer is returned.
+Example: Using `Decipher` objects as streams:
-Note: `hmac` object can not be used after `digest()` method has been
-called.
+```js
+const crypto = require('crypto');
+const decipher = crypto.createDecipher('aes192', 'a password');
+var decrypted = '';
+decipher.on('readable', () => {
+ var data = decipher.read();
+ if (data)
+ decrypted += data.toString('utf8');
+});
+decipher.on('end', () => {
+ console.log(decrypted);
+ // Prints: some clear text data
+});
-## crypto.createCipher(algorithm, password)
+var encrypted = 'ca981be48e90867604588e75d04feabb63cc007a8f8ad89b10616ed84d815504';
+decipher.write(encrypted, 'hex');
+decipher.end();
+```
-Creates and returns a cipher object, with the given algorithm and
-password.
+Example: Using `Decipher` and piped streams:
-`algorithm` is dependent on OpenSSL, examples are `'aes192'`, etc. On
-recent releases, `openssl list-cipher-algorithms` will display the
-available cipher algorithms. `password` is used to derive key and IV,
-which must be a `'binary'` encoded string or a [buffer](buffer.html).
+```js
+const crypto = require('crypto');
+const fs = require('fs');
+const decipher = crypto.createDecipher('aes192', 'a password');
-It is a [stream](stream.html) that is both readable and writable. The
-written data is used to compute the hash. Once the writable side of
-the stream is ended, use the `read()` method to get the computed hash
-digest. The legacy `update` and `digest` methods are also supported.
+const input = fs.createReadStream('test.enc');
+const output = fs.createWriteStream('test.js');
-## crypto.createCipheriv(algorithm, key, iv)
+input.pipe(decipher).pipe(output);
+```
-Creates and returns a cipher object, with the given algorithm, key and
-iv.
+Example: Using the [`decipher.update()`][] and [`decipher.final()`][] methods:
-`algorithm` is the same as the argument to `createCipher()`. `key` is
-the raw key used by the algorithm. `iv` is an [initialization
-vector](http://en.wikipedia.org/wiki/Initialization_vector).
+```js
+const crypto = require('crypto');
+const decipher = crypto.createDecipher('aes192', 'a password');
-`key` and `iv` must be `'binary'` encoded strings or
-[buffers](buffer.html).
+var encrypted = 'ca981be48e90867604588e75d04feabb63cc007a8f8ad89b10616ed84d815504';
+var decrypted = decipher.update(encrypted, 'hex', 'utf8');
+decrypted += decipher.final('utf8');
+console.log(decrypted);
+ // Prints: some clear text data
+```
-## Class: Cipher
+### decipher.final([output_encoding])
+
+Returns any remaining deciphered contents. If `output_encoding`
+parameter is one of `'binary'`, `'base64'` or `'hex'`, a string is returned.
+If an `output_encoding` is not provided, a [`Buffer`][] is returned.
+
+Once the `decipher.final()` method has been called, the `Decipher` object can
+no longer be used to decrypt data. Attempts to call `decipher.final()` more
+than once will result in an error being thrown.
+
+### decipher.setAAD(buffer)
+
+When using an authenticated encryption mode (only `GCM` is currently
+supported), the `cipher.setAAD()` method sets the value used for the
+_additional authenticated data_ (AAD) input parameter.
+
+### decipher.setAuthTag(buffer)
+
+When using an authenticated encryption mode (only `GCM` is 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()`][] with throw, indicating that the
+cipher text should be discarded due to failed authentication.
+
+### decipher.setAutoPadding(auto_padding=true)
-Class for encrypting data.
+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.
-Returned by `crypto.createCipher` and `crypto.createCipheriv`.
+Turning auto padding off will only work if the input data's length is a
+multiple of the ciphers block size.
-Cipher objects are [streams](stream.html) that are both readable and
-writable. The written plain text data is used to produce the
-encrypted data on the readable side. The legacy `update` and `final`
-methods are also supported.
+The `decipher.setAutoPadding()` method must be called before
+[`decipher.update()`][].
-### cipher.update(data, [input_encoding], [output_encoding])
+### decipher.update(data[, input_encoding][, output_encoding])
-Updates the cipher with `data`, the encoding of which is given in
-`input_encoding` and can be `'utf8'`, `'ascii'` or `'binary'`. If no
-encoding is provided, then a buffer is expected.
-If `data` is a `Buffer` then `input_encoding` is ignored.
+Updates the decipher with `data`. If the `input_encoding` argument is given,
+it's value must be one of `'binary'`, `'base64'`, or `'hex'` and the `data`
+argument is a string using the specified encoding. If the `input_encoding`
+argument is not given, `data` must be a [`Buffer`][]. If `data` is a
+[`Buffer`][] then `input_encoding` is ignored.
The `output_encoding` specifies the output format of the enciphered
-data, and can be `'binary'`, `'base64'` or `'hex'`. If no encoding is
-provided, then a buffer is returned.
+data, and can be `'binary'`, `'ascii'` or `'utf8'`. If the `output_encoding`
+is specified, a string using the specified encoding is returned. If no
+`output_encoding` is provided, a [`Buffer`][] is returned.
-Returns the enciphered contents, and can be called many times with new
-data as it is streamed.
+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.
-### cipher.final([output_encoding])
+## Class: DiffieHellman
-Returns any remaining enciphered contents, with `output_encoding`
-being one of: `'binary'`, `'base64'` or `'hex'`. If no encoding is
-provided, then a buffer is returned.
+The `DiffieHellman` class is a utility for creating Diffie-Hellman key
+exchanges.
-Note: `cipher` object can not be used after `final()` method has been
-called.
+Instances of the `DiffieHellman` class can be created using the
+[`crypto.createDiffieHellman()`][] function.
-### cipher.setAutoPadding(auto_padding=true)
+```js
+const crypto = require('crypto');
+const assert = require('assert');
-You can disable automatic padding of the input data to block size. If
-`auto_padding` is false, the length of the entire input data must be a
-multiple of the cipher's block size or `final` will fail. Useful for
-non-standard padding, e.g. using `0x0` instead of PKCS padding. You
-must call this before `cipher.final`.
+// Generate Alice's keys...
+const alice = crypto.createDiffieHellman(2048);
+const alice_key = alice.generateKeys();
-### cipher.getAuthTag()
+// Generate Bob's keys...
+const bob = crypto.createDiffieHellman(alice.getPrime(), alice.getGenerator());
+const bob_key = bob.generateKeys();
-For authenticated encryption modes (currently supported: GCM), this
-method returns a `Buffer` that represents the _authentication tag_ that
-has been computed from the given data. Should be called after
-encryption has been completed using the `final` method!
+// Exchange and generate the secret...
+const alice_secret = alice.computeSecret(bob_key);
+const bob_secret = bob.computeSecret(alice_key);
+// OK
+assert.equal(alice_secret.toString('hex'), bob_secret.toString('hex'));
+```
-## crypto.createDecipher(algorithm, password)
+### diffieHellman.computeSecret(other_public_key[, input_encoding][, output_encoding])
-Creates and returns a decipher object, with the given algorithm and
-key. This is the mirror of the [createCipher()][] above.
+Computes the shared secret using `other_public_key` as the other
+party's public key and returns the computed shared secret. The supplied
+key is interpreted using the specified `input_encoding`, and secret is
+encoded using specified `output_encoding`. Encodings can be
+`'binary'`, `'hex'`, or `'base64'`. If the `input_encoding` is not
+provided, `other_public_key` is expected to be a [`Buffer`][].
-## crypto.createDecipheriv(algorithm, key, iv)
+If `output_encoding` is given a string is returned; otherwise, a
+[`Buffer`][] is returned.
-Creates and returns a decipher object, with the given algorithm, key
-and iv. This is the mirror of the [createCipheriv()][] above.
+### diffieHellman.generateKeys([encoding])
-## Class: Decipher
+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. Encoding can be `'binary'`, `'hex'`,
+or `'base64'`. If `encoding` is provided a string is returned; otherwise a
+[`Buffer`][] is returned.
-Class for decrypting data.
+### diffieHellman.getGenerator([encoding])
-Returned by `crypto.createDecipher` and `crypto.createDecipheriv`.
+Returns the Diffie-Hellman generator in the specified `encoding`, which can
+be `'binary'`, `'hex'`, or `'base64'`. If `encoding` is provided a string is
+returned; otherwise a [`Buffer`][] is returned.
-Decipher objects are [streams](stream.html) that are both readable and
-writable. The written enciphered data is used to produce the
-plain-text data on the the readable side. The legacy `update` and
-`final` methods are also supported.
+### diffieHellman.getPrime([encoding])
-### decipher.update(data, [input_encoding], [output_encoding])
+Returns the Diffie-Hellman prime in the specified `encoding`, which can
+be `'binary'`, `'hex'`, or `'base64'`. If `encoding` is provided a string is
+returned; otherwise a [`Buffer`][] is returned.
-Updates the decipher with `data`, which is encoded in `'binary'`,
-`'base64'` or `'hex'`. If no encoding is provided, then a buffer is
-expected.
-If `data` is a `Buffer` then `input_encoding` is ignored.
+### diffieHellman.getPrivateKey([encoding])
-The `output_decoding` specifies in what format to return the
-deciphered plaintext: `'binary'`, `'ascii'` or `'utf8'`. If no
-encoding is provided, then a buffer is returned.
+Returns the Diffie-Hellman private key in the specified `encoding`,
+which can be `'binary'`, `'hex'`, or `'base64'`. If `encoding` is provided a
+string is returned; otherwise a [`Buffer`][] is returned.
-### decipher.final([output_encoding])
+### diffieHellman.getPublicKey([encoding])
-Returns any remaining plaintext which is deciphered, with
-`output_encoding` being one of: `'binary'`, `'ascii'` or `'utf8'`. If
-no encoding is provided, then a buffer is returned.
+Returns the Diffie-Hellman public key in the specified `encoding`, which
+can be `'binary'`, `'hex'`, or `'base64'`. If `encoding` is provided a
+string is returned; otherwise a [`Buffer`][] is returned.
-Note: `decipher` object can not be used after `final()` method has been
-called.
+### diffieHellman.setPrivateKey(private_key[, encoding])
-### decipher.setAutoPadding(auto_padding=true)
+Sets the Diffie-Hellman private key. If the `encoding` argument is provided
+and is either `'binary'`, `'hex'`, or `'base64'`, `private_key` is expected
+to be a string. If no `encoding` is provided, `private_key` is expected
+to be a [`Buffer`][].
-You can disable auto padding if the data has been encrypted without
-standard block padding to prevent `decipher.final` from checking and
-removing it. Can only work if the input data's length is a multiple of
-the ciphers block size. You must call this before streaming data to
-`decipher.update`.
+### diffieHellman.setPublicKey(public_key[, encoding])
-### decipher.setAuthTag(buffer)
+Sets the Diffie-Hellman public key. If the `encoding` argument is provided
+and is either `'binary'`, `'hex'` or `'base64'`, `public_key` is expected
+to be a string. If no `encoding` is provided, `public_key` is expected
+to be a [`Buffer`][].
-For authenticated encryption modes (currently supported: GCM), this
-method must be used to pass in the received _authentication tag_.
-If no tag is provided or if the ciphertext has been tampered with,
-`final` will throw, thus indicating that the ciphertext should
-be discarded due to failed authentication.
+### diffieHellman.verifyError
+A bit field containing any warnings and/or errors resulting from a check
+performed during initialization of the `DiffieHellman` object.
-## crypto.createSign(algorithm)
+The following values are valid for this property (as defined in `constants`
+module):
-Creates and returns a signing object, with the given algorithm. On
-recent OpenSSL releases, `openssl list-public-key-algorithms` will
-display the available signing algorithms. Examples are `'RSA-SHA256'`.
+* `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.
+
+```js
+const crypto = require('crypto');
+const assert = require('assert');
+
+// Generate Alice's keys...
+const alice = crypto.createECDH('secp521r1');
+const alice_key = alice.generateKeys();
+
+// Generate Bob's keys...
+const bob = crypto.createECDH('secp521r1');
+const bob_key = bob.generateKeys();
+
+// Exchange and generate the secret...
+const alice_secret = alice.computeSecret(bob_key);
+const bob_secret = bob.computeSecret(alice_key);
+
+assert(alice_secret, bob_secret);
+ // OK
+```
+
+### ecdh.computeSecret(other_public_key[, input_encoding][, output_encoding])
+
+Computes the shared secret using `other_public_key` as the other
+party's public key and returns the computed shared secret. The supplied
+key is interpreted using specified `input_encoding`, and the returned secret
+is encoded using the specified `output_encoding`. Encodings can be
+`'binary'`, `'hex'`, or `'base64'`. If the `input_encoding` is not
+provided, `other_public_key` is expected to be a [`Buffer`][].
+
+If `output_encoding` is given a string will be returned; otherwise a
+[`Buffer`][] is returned.
+
+### ecdh.generateKeys([encoding[, format]])
+
+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` arguments specifies point encoding and can be `'compressed'`,
+`'uncompressed'`, or `'hybrid'`. If `format` is not specified, the point will
+be returned in `'uncompressed'` format.
+
+The `encoding` argument can be `'binary'`, `'hex'`, or `'base64'`. If
+`encoding` is provided a string is returned; otherwise a [`Buffer`][]
+is returned.
+
+### ecdh.getPrivateKey([encoding])
+
+Returns the EC Diffie-Hellman private key in the specified `encoding`,
+which can be `'binary'`, `'hex'`, or `'base64'`. If `encoding` is provided
+a string is returned; otherwise a [`Buffer`][] is returned.
+
+### ecdh.getPublicKey([encoding[, format]])
+
+Returns the EC Diffie-Hellman public key in the specified `encoding` and
+`format`.
+
+The `format` argument specifies point encoding and can be `'compressed'`,
+`'uncompressed'`, or `'hybrid'`. If `format` is not specified the point will be
+returned in `'uncompressed'` format.
+
+The `encoding` argument can be `'binary'`, `'hex'`, or `'base64'`. If
+`encoding` is specified, a string is returned; otherwise a [`Buffer`][] is
+returned.
+
+### ecdh.setPrivateKey(private_key[, encoding])
+
+Sets the EC Diffie-Hellman private key. The `encoding` can be `'binary'`,
+`'hex'` or `'base64'`. If `encoding` is provided, `private_key` is expected
+to be a string; otherwise `private_key` is expected to be a [`Buffer`][]. If
+`private_key` 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(public_key[, encoding])
+
+ Stability: 0 - Deprecated
+
+Sets the EC Diffie-Hellman public key. Key encoding can be `'binary'`,
+`'hex'` or `'base64'`. If `encoding` is provided `public_key` is expected to
+be a string; otherwise a [`Buffer`][] 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):
+
+```js
+const crypto = require('crypto');
+const alice = crypto.createECDH('secp256k1');
+const bob = crypto.createECDH('secp256k1');
+
+// Note: This is a shortcut way to specify 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 alice_secret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
+const bob_secret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
+
+// alice_secret and bob_secret should be the same shared secret value
+console.log(alice_secret === bob_secret);
+```
+
+## 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()`][] and [`hash.digest()`][] methods to produce the
+ computed hash.
+
+The [`crypto.createHash()`][] method is used to create `Hash` instances. `Hash`
+objects are not to be created directly using the `new` keyword.
+
+Example: Using `Hash` objects as streams:
+
+```js
+const crypto = require('crypto');
+const hash = crypto.createHash('sha256');
+
+hash.on('readable', () => {
+ var 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:
+
+```js
+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:
+
+```js
+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). The `encoding` can be `'hex'`, `'binary'` or
+`'base64'`. 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[, input_encoding])
+
+Updates the hash content with the given `data`, the encoding of which
+is given in `input_encoding` and can be `'utf8'`, `'ascii'` or
+`'binary'`. If `encoding` is not provided, and the `data` is a string, an
+encoding of `'binary'` is enforced. If `data` is a [`Buffer`][] then
+`input_encoding` 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()`][] and [`hmac.digest()`][] methods to produce the
+ computed HMAC digest.
+
+The [`crypto.createHmac()`][] method is used to create `Hmac` instances. `Hmac`
+objects are not to be created directly using the `new` keyword.
+
+Example: Using `Hmac` objects as streams:
+
+```js
+const crypto = require('crypto');
+const hmac = crypto.createHmac('sha256', 'a secret');
+
+hmac.on('readable', () => {
+ var 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:
+
+```js
+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:
+
+```js
+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()`][].
+The `encoding` can be `'hex'`, `'binary'` or `'base64'`. 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[, input_encoding])
+
+Updates the `Hmac` content with the given `data`, the encoding of which
+is given in `input_encoding` and can be `'utf8'`, `'ascii'` or
+`'binary'`. If `encoding` is not provided, and the `data` is a string, an
+encoding of `'utf8'` is enforced. If `data` is a [`Buffer`][] then
+`input_encoding` is ignored.
+
+This can be called many times with new data as it is streamed.
## Class: Sign
-Class for generating signatures.
+The `Sign` Class is a utility for generating signatures. It can be used in one
+of two ways:
-Returned by `crypto.createSign`.
+- As a writable [stream][], where data to be signed is written and the
+ [`sign.sign()`][] method is used to generate and return the signature, or
+- Using the [`sign.update()`][] and [`sign.sign()`][] methods to produce the
+ signature.
-Sign objects are writable [streams](stream.html). The written data is
-used to generate the signature. Once all of the data has been
-written, the `sign` method will return the signature. The legacy
-`update` method is also supported.
+The [`crypto.createSign()`][] method is used to create `Sign` instances. `Sign`
+objects are not to be created directly using the `new` keyword.
-### sign.update(data)
+Example: Using `Sign` objects as streams:
-Updates the sign object with data. This can be called many times
-with new data as it is streamed.
+```js
+const crypto = require('crypto');
+const sign = crypto.createSign('RSA-SHA256');
-### sign.sign(private_key, [output_format])
+sign.write('some data to sign');
+sign.end();
-Calculates the signature on all the updated data passed through the
-sign.
+const private_key = getPrivateKeySomehow();
+console.log(sign.sign(private_key, 'hex'));
+ // Prints the calculated signature
+```
-`private_key` can be an object or a string. If `private_key` is a string, it is
-treated as the key with no passphrase.
+Example: Using the [`sign.update()`][] and [`sign.sign()`][] methods:
+
+```js
+const crypto = require('crypto');
+const sign = crypto.createSign('RSA-SHA256');
+
+sign.update('some data to sign');
+
+const private_key = getPrivateKeySomehow();
+console.log(sign.sign(private_key, 'hex'));
+ // Prints the calculated signature
+```
+
+A [`sign`][] instance can also be created by just passing in the digest
+algorithm name, in which case OpenSSL will infer the full signature algorithm
+from the type of the PEM-formatted private key, including algorithms that
+do not have directly exposed name constants, e.g. 'ecdsa-with-SHA256'.
+
+Example: signing using ECDSA with SHA256
+
+```js
+const crypto = require('crypto');
+const sign = crypto.createSign('sha256');
+
+sign.update('some data to sign');
+
+const private_key = '-----BEGIN EC PRIVATE KEY-----\n' +
+ 'MHcCAQEEIF+jnWY1D5kbVYDNvxxo/Y+ku2uJPDwS0r/VuPZQrjjVoAoGCCqGSM49\n' +
+ 'AwEHoUQDQgAEurOxfSxmqIRYzJVagdZfMMSjRNNhB8i3mXyIMq704m2m52FdfKZ2\n' +
+ 'pQhByd5eyj3lgZ7m7jbchtdgyOF8Io/1ng==\n' +
+ '-----END EC PRIVATE KEY-----\n';
+
+console.log(sign.sign(private_key).toString('hex'));
+```
+
+### sign.sign(private_key[, output_format])
-`private_key`:
+Calculates the signature on all the data passed through using either
+[`sign.update()`][] or [`sign.write()`][stream-writable-write].
-* `key` : A string holding the PEM encoded private key
-* `passphrase` : A string of passphrase for the private key
+The `private_key` argument can be an object or a string. If `private_key` is a
+string, it is treated as a raw key with no passphrase. If `private_key` is an
+object, it is interpreted as a hash containing two properties:
-Returns the signature in `output_format` which can be `'binary'`,
-`'hex'` or `'base64'`. If no encoding is provided, then a buffer is
+* `key` : {String} - PEM encoded private key
+* `passphrase` : {String} - passphrase for the private key
+
+The `output_format` can specify one of `'binary'`, `'hex'` or `'base64'`. If
+`output_format` is provided a string is returned; otherwise a [`Buffer`][] is
returned.
-Note: `sign` object can not be used after `sign()` method has been
-called.
+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.
-## crypto.createVerify(algorithm)
+### sign.update(data[, input_encoding])
-Creates and returns a verification object, with the given algorithm.
-This is the mirror of the signing object above.
+Updates the `Sign` content with the given `data`, the encoding of which
+is given in `input_encoding` and can be `'utf8'`, `'ascii'` or
+`'binary'`. If `encoding` is not provided, and the `data` is a string, an
+encoding of `'utf8'` is enforced. If `data` is a [`Buffer`][] then
+`input_encoding` is ignored.
+
+This can be called many times with new data as it is streamed.
## Class: Verify
-Class for verifying signatures.
+The `Verify` class is a utility for verifying signatures. It can be used in one
+of two ways:
+
+- As a writable [stream][] where written data is used to validate against the
+ supplied signature, or
+- Using the [`verify.update()`][] and [`verify.verify()`][] methods to verify
+ the signature.
+
+ The [`crypto.createSign()`][] method is used to create `Sign` instances.
+ `Sign` objects are not to be created directly using the `new` keyword.
+
+Example: Using `Verify` objects as streams:
+
+```js
+const crypto = require('crypto');
+const verify = crypto.createVerify('RSA-SHA256');
-Returned by `crypto.createVerify`.
+verify.write('some data to sign');
+verify.end();
-Verify objects are writable [streams](stream.html). The written data
-is used to validate against the supplied signature. Once all of the
-data has been written, the `verify` method will return true if the
-supplied signature is valid. The legacy `update` method is also
-supported.
+const public_key = getPublicKeySomehow();
+const signature = getSignatureToVerify();
+console.log(sign.verify(public_key, signature));
+ // Prints true or false
+```
-### verifier.update(data)
+Example: Using the [`verify.update()`][] and [`verify.verify()`][] methods:
-Updates the verifier object with data. This can be called many times
-with new data as it is streamed.
+```js
+const crypto = require('crypto');
+const verify = crypto.createVerify('RSA-SHA256');
-### verifier.verify(object, signature, [signature_format])
+verify.update('some data to sign');
-Verifies the signed data by using the `object` and `signature`.
-`object` is a string containing a PEM encoded object, which can be
-one of RSA public key, DSA public key, or X.509 certificate.
-`signature` is the previously calculated signature for the data, in
+const public_key = getPublicKeySomehow();
+const signature = getSignatureToVerify();
+console.log(verify.verify(public_key, signature));
+ // Prints true or false
+```
+
+### verifier.update(data[, input_encoding])
+
+Updates the `Verify` content with the given `data`, the encoding of which
+is given in `input_encoding` and can be `'utf8'`, `'ascii'` or
+`'binary'`. If `encoding` is not provided, and the `data` is a string, an
+encoding of `'utf8'` is enforced. If `data` is a [`Buffer`][] then
+`input_encoding` is ignored.
+
+This can be called many times with new data as it is streamed.
+
+### verifier.verify(object, signature[, signature_format])
+
+Verifies the provided data using the given `object` and `signature`.
+The `object` argument is a string containing a PEM encoded object, which can be
+one an RSA public key, a DSA public key, or an X.509 certificate.
+The `signature` argument is the previously calculated signature for the data, in
the `signature_format` which can be `'binary'`, `'hex'` or `'base64'`.
-If no encoding is specified, then a buffer is expected.
+If a `signature_format` is specified, the `signature` is expected to be a
+string; otherwise `signature` is expected to be a [`Buffer`][].
-Returns true or false depending on the validity of the signature for
+Returns `true` or `false` depending on the validity of the signature for
the data and public key.
-Note: `verifier` object can not be used after `verify()` method has been
-called.
+The `verifier` 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.createDiffieHellman(prime_length)
+### crypto.DEFAULT_ENCODING
-Creates a Diffie-Hellman key exchange object and generates a prime of
-the given bit length. The generator used is `2`.
+The default encoding to use for functions that can take either strings
+or [buffers][`Buffer`]. The default value is `'buffer'`, which makes methods
+default to [`Buffer`][] objects.
-## crypto.createDiffieHellman(prime, [encoding])
+The `crypto.DEFAULT_ENCODING` mechanism is provided for backwards compatibility
+with legacy programs that expect `'binary'` to be the default encoding.
-Creates a Diffie-Hellman key exchange object using the supplied prime.
-The generator used is `2`. Encoding can be `'binary'`, `'hex'`, or
-`'base64'`. If no encoding is specified, then a buffer is expected.
+New applications should expect the default to be `'buffer'`. This property may
+become deprecated in a future Node.js release.
-## Class: DiffieHellman
+### crypto.createCipher(algorithm, password)
-The class for creating Diffie-Hellman key exchanges.
+Creates and returns a `Cipher` object that uses the given `algorithm` and
+`password`.
-Returned by `crypto.createDiffieHellman`.
+The `algorithm` is dependent on OpenSSL, examples are `'aes192'`, etc. On
+recent OpenSSL releases, `openssl list-cipher-algorithms` will display the
+available cipher algorithms.
-### diffieHellman.generateKeys([encoding])
+The `password` is used to derive the cipher key and initialization vector (IV).
+The value must be either a `'binary'` encoded string or a [`Buffer`][].
-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. Encoding can be `'binary'`, `'hex'`,
-or `'base64'`. If no encoding is provided, then a buffer is returned.
+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.
-### diffieHellman.computeSecret(other_public_key, [input_encoding], [output_encoding])
+In line with OpenSSL's recommendation to use pbkdf2 instead of
+[`EVP_BytesToKey`][] it is recommended that developers derive a key and IV on
+their own using [`crypto.pbkdf2()`][] and to use [`crypto.createCipheriv()`][]
+to create the `Cipher` object.
-Computes the shared secret using `other_public_key` as the other
-party's public key and returns the computed shared secret. Supplied
-key is interpreted using specified `input_encoding`, and secret is
-encoded using specified `output_encoding`. Encodings can be
-`'binary'`, `'hex'`, or `'base64'`. If the input encoding is not
-provided, then a buffer is expected.
+### crypto.createCipheriv(algorithm, key, iv)
-If no output encoding is given, then a buffer is returned.
+Creates and returns a `Cipher` object, with the given `algorithm`, `key` and
+initialization vector (`iv`).
-### diffieHellman.getPrime([encoding])
+The `algorithm` is dependent on OpenSSL, examples are `'aes192'`, etc. On
+recent OpenSSL releases, `openssl list-cipher-algorithms` will display the
+available cipher algorithms.
-Returns the Diffie-Hellman prime in the specified encoding, which can
-be `'binary'`, `'hex'`, or `'base64'`. If no encoding is provided,
-then a buffer is returned.
+The `key` is the raw key used by the `algorithm` and `iv` is an
+[initialization vector][]. Both arguments must be `'binary'` encoded strings or
+[buffers][`Buffer`].
-### diffieHellman.getGenerator([encoding])
+### crypto.createCredentials(details)
-Returns the Diffie-Hellman generator in the specified encoding, which can
-be `'binary'`, `'hex'`, or `'base64'`. If no encoding is provided,
-then a buffer is returned.
+ Stability: 0 - Deprecated: Use [`tls.createSecureContext()`][] instead.
-### diffieHellman.getPublicKey([encoding])
+The `crypto.createCredentials()` method is a deprecated alias for creating
+and returning a `tls.SecureContext` object. The `crypto.createCredentials()`
+method should not be used.
-Returns the Diffie-Hellman public key in the specified encoding, which
-can be `'binary'`, `'hex'`, or `'base64'`. If no encoding is provided,
-then a buffer is returned.
+The optional `details` argument is a hash object with keys:
-### diffieHellman.getPrivateKey([encoding])
+* `pfx` : {String|Buffer} - PFX or PKCS12 encoded private
+ key, certificate and CA certificates
+* `key` : {String} - PEM encoded private key
+* `passphrase` : {String} - passphrase for the private key or PFX
+* `cert` : {String} - PEM encoded certificate
+* `ca` : {String|Array} - Either a string or array of strings of PEM encoded CA
+ certificates to trust.
+* `crl` : {String|Array} - Either a string or array of strings of PEM encoded CRLs
+ (Certificate Revocation List)
+* `ciphers`: {String} using the [OpenSSL cipher list format][] describing the
+ cipher algorithms to use or exclude.
+
+If no 'ca' details are given, Node.js will use Mozilla's default
+[publicly trusted list of CAs][].
+
+### crypto.createDecipher(algorithm, password)
+
+Creates and returns a `Decipher` object that uses the given `algorithm` and
+`password` (key).
+
+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 pbkdf2 instead of
+[`EVP_BytesToKey`][] it is recommended that developers derive a key and IV on
+their own using [`crypto.pbkdf2()`][] and to use [`crypto.createDecipheriv()`][]
+to create the `Decipher` object.
+
+### crypto.createDecipheriv(algorithm, key, iv)
+
+Creates and returns a `Decipher` object that uses the given `algorithm`, `key`
+and initialization vector (`iv`).
+
+The `algorithm` is dependent on OpenSSL, examples are `'aes192'`, etc. On
+recent OpenSSL releases, `openssl list-cipher-algorithms` will display the
+available cipher algorithms.
+
+The `key` is the raw key used by the `algorithm` and `iv` is an
+[initialization vector][]. Both arguments must be `'binary'` encoded strings or
+[buffers][`Buffer`].
+
+### crypto.createDiffieHellman(prime[, prime_encoding][, generator][, generator_encoding])
+
+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.
+
+The `prime_encoding` and `generator_encoding` arguments can be `'binary'`,
+`'hex'`, or `'base64'`.
+
+If `prime_encoding` is specified, `prime` is expected to be a string; otherwise
+a [`Buffer`][] is expected.
+
+If `generator_encoding` is specified, `generator` is expected to be a string;
+otherwise either a number or [`Buffer`][] is expected.
+
+### crypto.createDiffieHellman(prime_length[, generator])
+
+Creates a `DiffieHellman` key exchange object and generates a prime of
+`prime_length` bits using an optional specific numeric `generator`.
+If `generator` is not specified, the value `2` is used.
+
+### crypto.createECDH(curve_name)
+
+Creates an Elliptic Curve Diffie-Hellman (`ECDH`) key exchange object using a
+predefined curve specified by the `curve_name` 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)
+
+Creates and returns a `Hash` object that can be used to generate hash digests
+using the given `algorithm`.
+
+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-message-digest-algorithms` will
+display the available digest algorithms.
-Returns the Diffie-Hellman private key in the specified encoding,
-which can be `'binary'`, `'hex'`, or `'base64'`. If no encoding is
-provided, then a buffer is returned.
+Example: generating the sha256 sum of a file
-### diffieHellman.setPublicKey(public_key, [encoding])
+```js
+const filename = process.argv[2];
+const crypto = require('crypto');
+const fs = require('fs');
-Sets the Diffie-Hellman public key. Key encoding can be `'binary'`,
-`'hex'` or `'base64'`. If no encoding is provided, then a buffer is
-expected.
+const hash = crypto.createHash('sha256');
-### diffieHellman.setPrivateKey(private_key, [encoding])
+const input = fs.createReadStream(filename);
+input.on('readable', () => {
+ var data = input.read();
+ if (data)
+ hash.update(data);
+ else {
+ console.log(`${hash.digest('hex')} ${filename}`);
+ }
+});
+```
-Sets the Diffie-Hellman private key. Key encoding can be `'binary'`,
-`'hex'` or `'base64'`. If no encoding is provided, then a buffer is
-expected.
+### crypto.createHmac(algorithm, key)
-## crypto.getDiffieHellman(group_name)
+Creates and returns an `Hmac` object that uses the given `algorithm` and `key`.
-Creates a predefined Diffie-Hellman key exchange object. The
-supported groups are: `'modp1'`, `'modp2'`, `'modp5'` (defined in [RFC
-2412][]) and `'modp14'`, `'modp15'`, `'modp16'`, `'modp17'`,
-`'modp18'` (defined in [RFC 3526][]). The returned object mimics the
-interface of objects created by [crypto.createDiffieHellman()][]
-above, but will not allow to change the keys (with
-[diffieHellman.setPublicKey()][] for example). The advantage of using
-this routine is that the parties don't have to generate nor exchange
-group modulus beforehand, saving both processor and communication
-time.
+The `algorithm` is dependent on the available algorithms supported by the
+version of OpenSSL on the platform. Examples are `'sha256'`, `'sha512'`, etc.
+On recent releases of OpenSSL, `openssl list-message-digest-algorithms` will
+display the available digest algorithms.
+
+The `key` is the HMAC key used to generate the cryptographic HMAC hash.
+
+Example: generating the sha256 HMAC of a file
+
+```js
+const filename = process.argv[2];
+const crypto = require('crypto');
+const fs = require('fs');
+
+const hmac = crypto.createHmac('sha256', 'a secret');
+
+const input = fs.createReadStream(filename);
+input.on('readable', () => {
+ var data = input.read();
+ if (data)
+ hmac.update(data);
+ else {
+ console.log(`${hmac.digest('hex')} ${filename}`);
+ }
+});
+```
+
+### crypto.createSign(algorithm)
+
+Creates and returns a `Sign` object that uses the given `algorithm`. On
+recent OpenSSL releases, `openssl list-public-key-algorithms` will
+display the available signing algorithms. One example is `'RSA-SHA256'`.
+
+### crypto.createVerify(algorithm)
+
+Creates and returns a `Verify` object that uses the given algorithm. On
+recent OpenSSL releases, `openssl list-public-key-algorithms` will
+display the available signing algorithms. One example is `'RSA-SHA256'`.
+
+### crypto.getCiphers()
+
+Returns an array with the names of the supported cipher algorithms.
+
+Example:
+
+```js
+const ciphers = crypto.getCiphers();
+console.log(ciphers); // ['aes-128-cbc', 'aes-128-ccm', ...]
+```
+
+### crypto.getCurves()
+
+Returns an array with the names of the supported elliptic curves.
+
+Example:
+
+```js
+const curves = crypto.getCurves();
+console.log(curves); // ['secp256k1', 'secp384r1', ...]
+```
+
+### crypto.getDiffieHellman(group_name)
+
+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):
- var crypto = require('crypto');
- var alice = crypto.getDiffieHellman('modp5');
- var bob = crypto.getDiffieHellman('modp5');
+```js
+const crypto = require('crypto');
+const alice = crypto.getDiffieHellman('modp14');
+const bob = crypto.getDiffieHellman('modp14');
- alice.generateKeys();
- bob.generateKeys();
+alice.generateKeys();
+bob.generateKeys();
- var alice_secret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
- var bob_secret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
+const alice_secret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
+const bob_secret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
- /* alice_secret and bob_secret should be the same */
- console.log(alice_secret == bob_secret);
+/* alice_secret and bob_secret should be the same */
+console.log(alice_secret == bob_secret);
+```
-## crypto.pbkdf2(password, salt, iterations, keylen, [digest], callback)
+### crypto.getHashes()
-Asynchronous PBKDF2 function. Applies the selected HMAC digest function
-(default: SHA1) to derive a key of the requested length from the password,
-salt and number of iterations. The callback gets two arguments:
-`(err, derivedKey)`.
+Returns an array with the names of the supported hash algorithms.
Example:
- crypto.pbkdf2('secret', 'salt', 4096, 512, 'sha256', function(err, key) {
- if (err)
- throw err;
- console.log(key.toString('hex')); // 'c5e478d...1469e50'
- });
+```js
+const hashes = crypto.getHashes();
+console.log(hashes); // ['sha', 'sha1', 'sha1WithRSAEncryption', ...]
+```
+
+### crypto.pbkdf2(password, salt, iterations, keylen[, digest], callback)
-You can get a list of supported digest functions with
-[crypto.getHashes()](#crypto_crypto_gethashes).
+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`. If the `digest` algorithm is not specified,
+a default of `'sha1'` is used.
-## crypto.pbkdf2Sync(password, salt, iterations, keylen, [digest])
+The supplied `callback` function is called with two arguments: `err` and
+`derivedKey`. If an error occurs, `err` will be set; otherwise `err` will be
+null. The successfully generated `derivedKey` will be passed as a [`Buffer`][].
-Synchronous PBKDF2 function. Returns derivedKey or throws error.
+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.
-## crypto.randomBytes(size, [callback])
+The `salt` should also be as unique as possible. It is recommended that the
+salts are random and their lengths are greater than 16 bytes. See
+[NIST SP 800-132][] for details.
-Generates cryptographically strong pseudo-random data. Usage:
+Example:
- // async
- crypto.randomBytes(256, function(ex, buf) {
- if (ex) throw ex;
- console.log('Have %d bytes of random data: %s', buf.length, buf);
- });
+```js
+const crypto = require('crypto');
+crypto.pbkdf2('secret', 'salt', 100000, 512, 'sha512', (err, key) => {
+ if (err) throw err;
+ console.log(key.toString('hex')); // 'c5e478d...1469e50'
+});
+```
- // sync
- try {
- var buf = crypto.randomBytes(256);
- console.log('Have %d bytes of random data: %s', buf.length, buf);
- } catch (ex) {
- // handle error
- // most likely, entropy sources are drained
- }
+An array of supported digest functions can be retrieved using
+[`crypto.getHashes()`][].
-NOTE: Will throw error or invoke callback with error, if there is not enough
-accumulated entropy to generate cryptographically strong data. In other words,
-`crypto.randomBytes` without callback will not block even if all entropy sources
-are drained.
+### crypto.pbkdf2Sync(password, salt, iterations, keylen[, digest])
-## crypto.pseudoRandomBytes(size, [callback])
+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 the `digest` algorithm is not specified,
+a default of `'sha1'` is used.
-Generates *non*-cryptographically strong pseudo-random data. The data
-returned will be unique if it is sufficiently long, but is not
-necessarily unpredictable. For this reason, the output of this
-function should never be used where unpredictability is important,
-such as in the generation of encryption keys.
+If an error occurs an Error will be thrown, otherwise the derived key will be
+returned as a [`Buffer`][].
-Usage is otherwise identical to `crypto.randomBytes`.
+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.
-## Class: Certificate
+The `salt` should also be as unique as possible. It is recommended that the
+salts are random and their lengths are greater than 16 bytes. See
+[NIST SP 800-132][] for details.
-The class used for working with signed public key & challenges. The most
-common usage for this series of functions is when dealing with the `<keygen>`
-element. http://www.openssl.org/docs/apps/spkac.html
+Example:
-Returned by `crypto.Certificate`.
+```js
+const crypto = require('crypto');
+const key = crypto.pbkdf2Sync('secret', 'salt', 100000, 512, 'sha512');
+console.log(key.toString('hex')); // 'c5e478d...1469e50'
+```
-### Certificate.verifySpkac(spkac)
+An array of supported digest functions can be retrieved using
+[`crypto.getHashes()`][].
-Returns true of false based on the validity of the SPKAC.
+### crypto.privateDecrypt(private_key, buffer)
-### Certificate.exportChallenge(spkac)
+Decrypts `buffer` with `private_key`.
-Exports the encoded public key from the supplied SPKAC.
+`private_key` can be an object or a string. If `private_key` is a string, it is
+treated as the key with no passphrase and will use `RSA_PKCS1_OAEP_PADDING`.
+If `private_key` is an object, it is interpreted as a hash object with the
+keys:
-### Certificate.exportPublicKey(spkac)
+* `key` : {String} - PEM encoded private key
+* `passphrase` : {String} - Optional passphrase for the private key
+* `padding` : An optional padding value, one of the following:
+ * `constants.RSA_NO_PADDING`
+ * `constants.RSA_PKCS1_PADDING`
+ * `constants.RSA_PKCS1_OAEP_PADDING`
-Exports the encoded challenge associated with the SPKAC.
+All paddings are defined in the `constants` module.
-## crypto.DEFAULT_ENCODING
+### crypto.privateEncrypt(private_key, buffer)
-The default encoding to use for functions that can take either strings
-or buffers. The default value is `'buffer'`, which makes it default
-to using Buffer objects. This is here to make the crypto module more
-easily compatible with legacy programs that expected `'binary'` to be
-the default encoding.
-
-Note that new programs will probably expect buffers, so only use this
-as a temporary measure.
-
-## Recent API Changes
-
-The Crypto module was added to Node before there was the concept of a
-unified Stream API, and before there were Buffer objects for handling
-binary data.
-
-As such, the streaming classes don't have the typical methods found on
-other Node classes, and many methods accepted and returned
-Binary-encoded strings by default rather than Buffers. This was
-changed to use Buffers by default instead.
-
-This is a breaking change for some use cases, but not all.
-
-For example, if you currently use the default arguments to the Sign
-class, and then pass the results to the Verify class, without ever
-inspecting the data, then it will continue to work as before. Where
-you once got a binary string and then presented the binary string to
-the Verify object, you'll now get a Buffer, and present the Buffer to
-the Verify object.
-
-However, if you were doing things with the string data that will not
-work properly on Buffers (such as, concatenating them, storing in
-databases, etc.), or you are passing binary strings to the crypto
-functions without an encoding argument, then you will need to start
-providing encoding arguments to specify which encoding you'd like to
-use. To switch to the previous style of using binary strings by
-default, set the `crypto.DEFAULT_ENCODING` field to 'binary'. Note
-that new programs will probably expect buffers, so only use this as a
-temporary measure.
-
-
-[createCipher()]: #crypto_crypto_createcipher_algorithm_password
-[createCipheriv()]: #crypto_crypto_createcipheriv_algorithm_key_iv
-[crypto.createDiffieHellman()]: #crypto_crypto_creatediffiehellman_prime_encoding
-[diffieHellman.setPublicKey()]: #crypto_diffiehellman_setpublickey_public_key_encoding
-[RFC 2412]: http://www.rfc-editor.org/rfc/rfc2412.txt
-[RFC 3526]: http://www.rfc-editor.org/rfc/rfc3526.txt
+Encrypts `buffer` with `private_key`.
+
+`private_key` can be an object or a string. If `private_key` is a string, it is
+treated as the key with no passphrase and will use `RSA_PKCS1_PADDING`.
+If `private_key` is an object, it is interpreted as a hash object with the
+keys:
+
+* `key` : {String} - PEM encoded private key
+* `passphrase` : {String} - Optional passphrase for the private key
+* `padding` : An optional padding value, one of the following:
+ * `constants.RSA_NO_PADDING`
+ * `constants.RSA_PKCS1_PADDING`
+ * `constants.RSA_PKCS1_OAEP_PADDING`
+
+All paddings are defined in the `constants` module.
+
+### crypto.publicDecrypt(public_key, buffer)
+
+Decrypts `buffer` with `public_key`.
+
+`public_key` can be an object or a string. If `public_key` is a string, it is
+treated as the key with no passphrase and will use `RSA_PKCS1_PADDING`.
+If `public_key` is an object, it is interpreted as a hash object with the
+keys:
+
+* `key` : {String} - PEM encoded public key
+* `passphrase` : {String} - Optional passphrase for the private key
+* `padding` : An optional padding value, one of the following:
+ * `constants.RSA_NO_PADDING`
+ * `constants.RSA_PKCS1_PADDING`
+ * `constants.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.
+
+All paddings are defined in the `constants` module.
+
+### crypto.publicEncrypt(public_key, buffer)
+
+Encrypts `buffer` with `public_key`.
+
+`public_key` can be an object or a string. If `public_key` is a string, it is
+treated as the key with no passphrase and will use `RSA_PKCS1_OAEP_PADDING`.
+If `public_key` is an object, it is interpreted as a hash object with the
+keys:
+
+* `key` : {String} - PEM encoded public key
+* `passphrase` : {String} - Optional passphrase for the private key
+* `padding` : An optional padding value, one of the following:
+ * `constants.RSA_NO_PADDING`
+ * `constants.RSA_PKCS1_PADDING`
+ * `constants.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.
+
+All paddings are defined in the `constants` module.
+
+### crypto.randomBytes(size[, callback])
+
+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.
+
+```js
+// Asynchronous
+const crypto = require('crypto');
+crypto.randomBytes(256, (err, buf) => {
+ if (err) throw err;
+ console.log(`${buf.length} bytes of random data: ${buf.toString('hex')}`);
+});
+```
+
+If the `callback` function is not provided, the random bytes are generated
+synchronously and returned as a [`Buffer`][]. An error will be thrown if
+there is a problem generating the bytes.
+
+```js
+// Synchronous
+const buf = crypto.randomBytes(256);
+console.log(
+ `${buf.length} bytes of random data: ${buf.toString('hex')}`);
+```
+
+The `crypto.randomBytes()` method will block until there is sufficient entropy.
+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.
+
+### crypto.setEngine(engine[, flags])
+
+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 the
+`constants` module):
+
+* `ENGINE_METHOD_RSA`
+* `ENGINE_METHOD_DSA`
+* `ENGINE_METHOD_DH`
+* `ENGINE_METHOD_RAND`
+* `ENGINE_METHOD_ECDH`
+* `ENGINE_METHOD_ECDSA`
+* `ENGINE_METHOD_CIPHERS`
+* `ENGINE_METHOD_DIGESTS`
+* `ENGINE_METHOD_STORE`
+* `ENGINE_METHOD_PKEY_METH`
+* `ENGINE_METHOD_PKEY_ASN1_METH`
+* `ENGINE_METHOD_ALL`
+* `ENGINE_METHOD_NONE`
+
+## 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][stream]
+API (e.g. `update()`, `final()`, or `digest()`). Also, many methods accepted
+and returned `'binary'` encoded strings by default rather than Buffers. 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` and `modp5` have a key size
+ smaller than 2048 bits and are not recommended.
+
+See the reference for other recommendations and details.
+
+[`Buffer`]: buffer.html
+[`cipher.final()`]: #crypto_cipher_final_output_encoding
+[`cipher.update()`]: #crypto_cipher_update_data_input_encoding_output_encoding
+[`crypto.createCipher()`]: #crypto_crypto_createcipher_algorithm_password
+[`crypto.createCipheriv()`]: #crypto_crypto_createcipheriv_algorithm_key_iv
+[`crypto.createDecipher()`]: #crypto_crypto_createdecipher_algorithm_password
+[`crypto.createDecipheriv()`]: #crypto_crypto_createdecipheriv_algorithm_key_iv
+[`crypto.createDiffieHellman()`]: #crypto_crypto_creatediffiehellman_prime_prime_encoding_generator_generator_encoding
+[`crypto.createECDH()`]: #crypto_crypto_createecdh_curve_name
+[`crypto.createHash()`]: #crypto_crypto_createhash_algorithm
+[`crypto.createHmac()`]: #crypto_crypto_createhmac_algorithm_key
+[`crypto.createSign()`]: #crypto_crypto_createsign_algorithm
+[`crypto.getCurves()`]: #crypto_crypto_getcurves
+[`crypto.getHashes()`]: #crypto_crypto_gethashes
+[`crypto.pbkdf2()`]: #crypto_crypto_pbkdf2_password_salt_iterations_keylen_digest_callback
+[`decipher.final()`]: #crypto_decipher_final_output_encoding
+[`decipher.update()`]: #crypto_decipher_update_data_input_encoding_output_encoding
+[`diffieHellman.setPublicKey()`]: #crypto_diffiehellman_setpublickey_public_key_encoding
+[`ecdh.generateKeys()`]: #crypto_ecdh_generatekeys_encoding_format
+[`ecdh.setPrivateKey()`]: #crypto_ecdh_setprivatekey_private_key_encoding
+[`ecdh.setPublicKey()`]: #crypto_ecdh_setpublickey_public_key_encoding
+[`EVP_BytesToKey`]: https://www.openssl.org/docs/crypto/EVP_BytesToKey.html
+[`hash.digest()`]: #crypto_hash_digest_encoding
+[`hash.update()`]: #crypto_hash_update_data_input_encoding
+[`hmac.digest()`]: #crypto_hmac_digest_encoding
+[`hmac.update()`]: #crypto_hmac_update_data
+[`sign.sign()`]: #crypto_sign_sign_private_key_output_format
+[`sign.update()`]: #crypto_sign_update_data
+[`tls.createSecureContext()`]: tls.html#tls_tls_createsecurecontext_details
+[`verify.update()`]: #crypto_verifier_update_data
+[`verify.verify()`]: #crypto_verifier_verify_object_signature_signature_format
+[Caveats]: #crypto_support_for_weak_or_compromised_algorithms
+[HTML5's `keygen` element]: http://www.w3.org/TR/html5/forms.html#the-keygen-element
+[initialization vector]: https://en.wikipedia.org/wiki/Initialization_vector
+[NIST SP 800-131A]: http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-131Ar1.pdf
+[NIST SP 800-132]: http://csrc.nist.gov/publications/nistpubs/800-132/nist-sp800-132.pdf
+[OpenSSL cipher list format]: https://www.openssl.org/docs/apps/ciphers.html#CIPHER_LIST_FORMAT
+[OpenSSL's SPKAC implementation]: https://www.openssl.org/docs/apps/spkac.html
+[publicly trusted list of CAs]: https://mxr.mozilla.org/mozilla/source/security/nss/lib/ckfw/builtins/certdata.txt
+[RFC 2412]: https://www.rfc-editor.org/rfc/rfc2412.txt
+[RFC 3526]: https://www.rfc-editor.org/rfc/rfc3526.txt
+[stream]: stream.html
+[stream-writable-write]: stream.html#stream_writable_write_chunk_encoding_callback
projects / platform / upstream / nodejs.git / blobdiff