/**
* Password-based encryption functions.
*
* @author Dave Longley
* @author Stefan Siegl <stesie@brokenpipe.de>
*
* Copyright (c) 2010-2013 Digital Bazaar, Inc.
* Copyright (c) 2012 Stefan Siegl <stesie@brokenpipe.de>
*
* An EncryptedPrivateKeyInfo:
*
* EncryptedPrivateKeyInfo ::= SEQUENCE {
* encryptionAlgorithm EncryptionAlgorithmIdentifier,
* encryptedData EncryptedData }
*
* EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier
*
* EncryptedData ::= OCTET STRING
*/
var forge = require('./forge');
require('./aes');
require('./asn1');
require('./des');
require('./md');
require('./oids');
require('./pbkdf2');
require('./pem');
require('./random');
require('./rc2');
require('./rsa');
require('./util');
if(typeof BigInteger === 'undefined') {
var BigInteger = forge.jsbn.BigInteger;
}
// shortcut for asn.1 API
var asn1 = forge.asn1;
/* Password-based encryption implementation. */
var pki = forge.pki = forge.pki || {};
module.exports = pki.pbe = forge.pbe = forge.pbe || {};
var oids = pki.oids;
// validator for an EncryptedPrivateKeyInfo structure
// Note: Currently only works w/algorithm params
var encryptedPrivateKeyValidator = {
name: 'EncryptedPrivateKeyInfo',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.SEQUENCE,
constructed: true,
value: [{
name: 'EncryptedPrivateKeyInfo.encryptionAlgorithm',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.SEQUENCE,
constructed: true,
value: [{
name: 'AlgorithmIdentifier.algorithm',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.OID,
constructed: false,
capture: 'encryptionOid'
}, {
name: 'AlgorithmIdentifier.parameters',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.SEQUENCE,
constructed: true,
captureAsn1: 'encryptionParams'
}]
}, {
// encryptedData
name: 'EncryptedPrivateKeyInfo.encryptedData',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.OCTETSTRING,
constructed: false,
capture: 'encryptedData'
}]
};
// validator for a PBES2Algorithms structure
// Note: Currently only works w/PBKDF2 + AES encryption schemes
var PBES2AlgorithmsValidator = {
name: 'PBES2Algorithms',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.SEQUENCE,
constructed: true,
value: [{
name: 'PBES2Algorithms.keyDerivationFunc',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.SEQUENCE,
constructed: true,
value: [{
name: 'PBES2Algorithms.keyDerivationFunc.oid',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.OID,
constructed: false,
capture: 'kdfOid'
}, {
name: 'PBES2Algorithms.params',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.SEQUENCE,
constructed: true,
value: [{
name: 'PBES2Algorithms.params.salt',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.OCTETSTRING,
constructed: false,
capture: 'kdfSalt'
}, {
name: 'PBES2Algorithms.params.iterationCount',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.INTEGER,
constructed: false,
capture: 'kdfIterationCount'
}, {
name: 'PBES2Algorithms.params.keyLength',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.INTEGER,
constructed: false,
optional: true,
capture: 'keyLength'
}, {
// prf
name: 'PBES2Algorithms.params.prf',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.SEQUENCE,
constructed: true,
optional: true,
value: [{
name: 'PBES2Algorithms.params.prf.algorithm',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.OID,
constructed: false,
capture: 'prfOid'
}]
}]
}]
}, {
name: 'PBES2Algorithms.encryptionScheme',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.SEQUENCE,
constructed: true,
value: [{
name: 'PBES2Algorithms.encryptionScheme.oid',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.OID,
constructed: false,
capture: 'encOid'
}, {
name: 'PBES2Algorithms.encryptionScheme.iv',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.OCTETSTRING,
constructed: false,
capture: 'encIv'
}]
}]
};
var pkcs12PbeParamsValidator = {
name: 'pkcs-12PbeParams',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.SEQUENCE,
constructed: true,
value: [{
name: 'pkcs-12PbeParams.salt',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.OCTETSTRING,
constructed: false,
capture: 'salt'
}, {
name: 'pkcs-12PbeParams.iterations',
tagClass: asn1.Class.UNIVERSAL,
type: asn1.Type.INTEGER,
constructed: false,
capture: 'iterations'
}]
};
/**
* Encrypts a ASN.1 PrivateKeyInfo object, producing an EncryptedPrivateKeyInfo.
*
* PBES2Algorithms ALGORITHM-IDENTIFIER ::=
* { {PBES2-params IDENTIFIED BY id-PBES2}, ...}
*
* id-PBES2 OBJECT IDENTIFIER ::= {pkcs-5 13}
*
* PBES2-params ::= SEQUENCE {
* keyDerivationFunc AlgorithmIdentifier {{PBES2-KDFs}},
* encryptionScheme AlgorithmIdentifier {{PBES2-Encs}}
* }
*
* PBES2-KDFs ALGORITHM-IDENTIFIER ::=
* { {PBKDF2-params IDENTIFIED BY id-PBKDF2}, ... }
*
* PBES2-Encs ALGORITHM-IDENTIFIER ::= { ... }
*
* PBKDF2-params ::= SEQUENCE {
* salt CHOICE {
* specified OCTET STRING,
* otherSource AlgorithmIdentifier {{PBKDF2-SaltSources}}
* },
* iterationCount INTEGER (1..MAX),
* keyLength INTEGER (1..MAX) OPTIONAL,
* prf AlgorithmIdentifier {{PBKDF2-PRFs}} DEFAULT algid-hmacWithSHA1
* }
*
* @param obj the ASN.1 PrivateKeyInfo object.
* @param password the password to encrypt with.
* @param options:
* algorithm the encryption algorithm to use
* ('aes128', 'aes192', 'aes256', '3des'), defaults to 'aes128'.
* count the iteration count to use.
* saltSize the salt size to use.
* prfAlgorithm the PRF message digest algorithm to use
* ('sha1', 'sha224', 'sha256', 'sha384', 'sha512')
*
* @return the ASN.1 EncryptedPrivateKeyInfo.
*/
pki.encryptPrivateKeyInfo = function(obj, password, options) {
// set default options
options = options || {};
options.saltSize = options.saltSize || 8;
options.count = options.count || 2048;
options.algorithm = options.algorithm || 'aes128';
options.prfAlgorithm = options.prfAlgorithm || 'sha1';
// generate PBE params
var salt = forge.random.getBytesSync(options.saltSize);
var count = options.count;
var countBytes = asn1.integerToDer(count);
var dkLen;
var encryptionAlgorithm;
var encryptedData;
if(options.algorithm.indexOf('aes') === 0 || options.algorithm === 'des') {
// do PBES2
var ivLen, encOid, cipherFn;
switch(options.algorithm) {
case 'aes128':
dkLen = 16;
ivLen = 16;
encOid = oids['aes128-CBC'];
cipherFn = forge.aes.createEncryptionCipher;
break;
case 'aes192':
dkLen = 24;
ivLen = 16;
encOid = oids['aes192-CBC'];
cipherFn = forge.aes.createEncryptionCipher;
break;
case 'aes256':
dkLen = 32;
ivLen = 16;
encOid = oids['aes256-CBC'];
cipherFn = forge.aes.createEncryptionCipher;
break;
case 'des':
dkLen = 8;
ivLen = 8;
encOid = oids['desCBC'];
cipherFn = forge.des.createEncryptionCipher;
break;
default:
var error = new Error('Cannot encrypt private key. Unknown encryption algorithm.');
error.algorithm = options.algorithm;
throw error;
}
// get PRF message digest
var prfAlgorithm = 'hmacWith' + options.prfAlgorithm.toUpperCase();
var md = prfAlgorithmToMessageDigest(prfAlgorithm);
// encrypt private key using pbe SHA-1 and AES/DES
var dk = forge.pkcs5.pbkdf2(password, salt, count, dkLen, md);
var iv = forge.random.getBytesSync(ivLen);
var cipher = cipherFn(dk);
cipher.start(iv);
cipher.update(asn1.toDer(obj));
cipher.finish();
encryptedData = cipher.output.getBytes();
// get PBKDF2-params
var params = createPbkdf2Params(salt, countBytes, dkLen, prfAlgorithm);
encryptionAlgorithm = asn1.create(
asn1.Class.UNIVERSAL, asn1.Type.SEQUENCE, true, [
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.OID, false,
asn1.oidToDer(oids['pkcs5PBES2']).getBytes()),
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.SEQUENCE, true, [
// keyDerivationFunc
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.SEQUENCE, true, [
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.OID, false,
asn1.oidToDer(oids['pkcs5PBKDF2']).getBytes()),
// PBKDF2-params
params
]),
// encryptionScheme
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.SEQUENCE, true, [
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.OID, false,
asn1.oidToDer(encOid).getBytes()),
// iv
asn1.create(
asn1.Class.UNIVERSAL, asn1.Type.OCTETSTRING, false, iv)
])
])
]);
} else if(options.algorithm === '3des') {
// Do PKCS12 PBE
dkLen = 24;
var saltBytes = new forge.util.ByteBuffer(salt);
var dk = pki.pbe.generatePkcs12Key(password, saltBytes, 1, count, dkLen);
var iv = pki.pbe.generatePkcs12Key(password, saltBytes, 2, count, dkLen);
var cipher = forge.des.createEncryptionCipher(dk);
cipher.start(iv);
cipher.update(asn1.toDer(obj));
cipher.finish();
encryptedData = cipher.output.getBytes();
encryptionAlgorithm = asn1.create(
asn1.Class.UNIVERSAL, asn1.Type.SEQUENCE, true, [
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.OID, false,
asn1.oidToDer(oids['pbeWithSHAAnd3-KeyTripleDES-CBC']).getBytes()),
// pkcs-12PbeParams
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.SEQUENCE, true, [
// salt
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.OCTETSTRING, false, salt),
// iteration count
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.INTEGER, false,
countBytes.getBytes())
])
]);
} else {
var error = new Error('Cannot encrypt private key. Unknown encryption algorithm.');
error.algorithm = options.algorithm;
throw error;
}
// EncryptedPrivateKeyInfo
var rval = asn1.create(asn1.Class.UNIVERSAL, asn1.Type.SEQUENCE, true, [
// encryptionAlgorithm
encryptionAlgorithm,
// encryptedData
asn1.create(
asn1.Class.UNIVERSAL, asn1.Type.OCTETSTRING, false, encryptedData)
]);
return rval;
};
/**
* Decrypts a ASN.1 PrivateKeyInfo object.
*
* @param obj the ASN.1 EncryptedPrivateKeyInfo object.
* @param password the password to decrypt with.
*
* @return the ASN.1 PrivateKeyInfo on success, null on failure.
*/
pki.decryptPrivateKeyInfo = function(obj, password) {
var rval = null;
// get PBE params
var capture = {};
var errors = [];
if(!asn1.validate(obj, encryptedPrivateKeyValidator, capture, errors)) {
var error = new Error('Cannot read encrypted private key. ' +
'ASN.1 object is not a supported EncryptedPrivateKeyInfo.');
error.errors = errors;
throw error;
}
// get cipher
var oid = asn1.derToOid(capture.encryptionOid);
var cipher = pki.pbe.getCipher(oid, capture.encryptionParams, password);
// get encrypted data
var encrypted = forge.util.createBuffer(capture.encryptedData);
cipher.update(encrypted);
if(cipher.finish()) {
rval = asn1.fromDer(cipher.output);
}
return rval;
};
/**
* Converts a EncryptedPrivateKeyInfo to PEM format.
*
* @param epki the EncryptedPrivateKeyInfo.
* @param maxline the maximum characters per line, defaults to 64.
*
* @return the PEM-formatted encrypted private key.
*/
pki.encryptedPrivateKeyToPem = function(epki, maxline) {
// convert to DER, then PEM-encode
var msg = {
type: 'ENCRYPTED PRIVATE KEY',
body: asn1.toDer(epki).getBytes()
};
return forge.pem.encode(msg, {maxline: maxline});
};
/**
* Converts a PEM-encoded EncryptedPrivateKeyInfo to ASN.1 format. Decryption
* is not performed.
*
* @param pem the EncryptedPrivateKeyInfo in PEM-format.
*
* @return the ASN.1 EncryptedPrivateKeyInfo.
*/
pki.encryptedPrivateKeyFromPem = function(pem) {
var msg = forge.pem.decode(pem)[0];
if(msg.type !== 'ENCRYPTED PRIVATE KEY') {
var error = new Error('Could not convert encrypted private key from PEM; ' +
'PEM header type is "ENCRYPTED PRIVATE KEY".');
error.headerType = msg.type;
throw error;
}
if(msg.procType && msg.procType.type === 'ENCRYPTED') {
throw new Error('Could not convert encrypted private key from PEM; ' +
'PEM is encrypted.');
}
// convert DER to ASN.1 object
return asn1.fromDer(msg.body);
};
/**
* Encrypts an RSA private key. By default, the key will be wrapped in
* a PrivateKeyInfo and encrypted to produce a PKCS#8 EncryptedPrivateKeyInfo.
* This is the standard, preferred way to encrypt a private key.
*
* To produce a non-standard PEM-encrypted private key that uses encapsulated
* headers to indicate the encryption algorithm (old-style non-PKCS#8 OpenSSL
* private key encryption), set the 'legacy' option to true. Note: Using this
* option will cause the iteration count to be forced to 1.
*
* Note: The 'des' algorithm is supported, but it is not considered to be
* secure because it only uses a single 56-bit key. If possible, it is highly
* recommended that a different algorithm be used.
*
* @param rsaKey the RSA key to encrypt.
* @param password the password to use.
* @param options:
* algorithm: the encryption algorithm to use
* ('aes128', 'aes192', 'aes256', '3des', 'des').
* count: the iteration count to use.
* saltSize: the salt size to use.
* legacy: output an old non-PKCS#8 PEM-encrypted+encapsulated
* headers (DEK-Info) private key.
*
* @return the PEM-encoded ASN.1 EncryptedPrivateKeyInfo.
*/
pki.encryptRsaPrivateKey = function(rsaKey, password, options) {
// standard PKCS#8
options = options || {};
if(!options.legacy) {
// encrypt PrivateKeyInfo
var rval = pki.wrapRsaPrivateKey(pki.privateKeyToAsn1(rsaKey));
rval = pki.encryptPrivateKeyInfo(rval, password, options);
return pki.encryptedPrivateKeyToPem(rval);
}
// legacy non-PKCS#8
var algorithm;
var iv;
var dkLen;
var cipherFn;
switch(options.algorithm) {
case 'aes128':
algorithm = 'AES-128-CBC';
dkLen = 16;
iv = forge.random.getBytesSync(16);
cipherFn = forge.aes.createEncryptionCipher;
break;
case 'aes192':
algorithm = 'AES-192-CBC';
dkLen = 24;
iv = forge.random.getBytesSync(16);
cipherFn = forge.aes.createEncryptionCipher;
break;
case 'aes256':
algorithm = 'AES-256-CBC';
dkLen = 32;
iv = forge.random.getBytesSync(16);
cipherFn = forge.aes.createEncryptionCipher;
break;
case '3des':
algorithm = 'DES-EDE3-CBC';
dkLen = 24;
iv = forge.random.getBytesSync(8);
cipherFn = forge.des.createEncryptionCipher;
break;
case 'des':
algorithm = 'DES-CBC';
dkLen = 8;
iv = forge.random.getBytesSync(8);
cipherFn = forge.des.createEncryptionCipher;
break;
default:
var error = new Error('Could not encrypt RSA private key; unsupported ' +
'encryption algorithm "' + options.algorithm + '".');
error.algorithm = options.algorithm;
throw error;
}
// encrypt private key using OpenSSL legacy key derivation
var dk = forge.pbe.opensslDeriveBytes(password, iv.substr(0, 8), dkLen);
var cipher = cipherFn(dk);
cipher.start(iv);
cipher.update(asn1.toDer(pki.privateKeyToAsn1(rsaKey)));
cipher.finish();
var msg = {
type: 'RSA PRIVATE KEY',
procType: {
version: '4',
type: 'ENCRYPTED'
},
dekInfo: {
algorithm: algorithm,
parameters: forge.util.bytesToHex(iv).toUpperCase()
},
body: cipher.output.getBytes()
};
return forge.pem.encode(msg);
};
/**
* Decrypts an RSA private key.
*
* @param pem the PEM-formatted EncryptedPrivateKeyInfo to decrypt.
* @param password the password to use.
*
* @return the RSA key on success, null on failure.
*/
pki.decryptRsaPrivateKey = function(pem, password) {
var rval = null;
var msg = forge.pem.decode(pem)[0];
if(msg.type !== 'ENCRYPTED PRIVATE KEY' &&
msg.type !== 'PRIVATE KEY' &&
msg.type !== 'RSA PRIVATE KEY') {
var error = new Error('Could not convert private key from PEM; PEM header type ' +
'is not "ENCRYPTED PRIVATE KEY", "PRIVATE KEY", or "RSA PRIVATE KEY".');
error.headerType = error;
throw error;
}
if(msg.procType && msg.procType.type === 'ENCRYPTED') {
var dkLen;
var cipherFn;
switch(msg.dekInfo.algorithm) {
case 'DES-CBC':
dkLen = 8;
cipherFn = forge.des.createDecryptionCipher;
break;
case 'DES-EDE3-CBC':
dkLen = 24;
cipherFn = forge.des.createDecryptionCipher;
break;
case 'AES-128-CBC':
dkLen = 16;
cipherFn = forge.aes.createDecryptionCipher;
break;
case 'AES-192-CBC':
dkLen = 24;
cipherFn = forge.aes.createDecryptionCipher;
break;
case 'AES-256-CBC':
dkLen = 32;
cipherFn = forge.aes.createDecryptionCipher;
break;
case 'RC2-40-CBC':
dkLen = 5;
cipherFn = function(key) {
return forge.rc2.createDecryptionCipher(key, 40);
};
break;
case 'RC2-64-CBC':
dkLen = 8;
cipherFn = function(key) {
return forge.rc2.createDecryptionCipher(key, 64);
};
break;
case 'RC2-128-CBC':
dkLen = 16;
cipherFn = function(key) {
return forge.rc2.createDecryptionCipher(key, 128);
};
break;
default:
var error = new Error('Could not decrypt private key; unsupported ' +
'encryption algorithm "' + msg.dekInfo.algorithm + '".');
error.algorithm = msg.dekInfo.algorithm;
throw error;
}
// use OpenSSL legacy key derivation
var iv = forge.util.hexToBytes(msg.dekInfo.parameters);
var dk = forge.pbe.opensslDeriveBytes(password, iv.substr(0, 8), dkLen);
var cipher = cipherFn(dk);
cipher.start(iv);
cipher.update(forge.util.createBuffer(msg.body));
if(cipher.finish()) {
rval = cipher.output.getBytes();
} else {
return rval;
}
} else {
rval = msg.body;
}
if(msg.type === 'ENCRYPTED PRIVATE KEY') {
rval = pki.decryptPrivateKeyInfo(asn1.fromDer(rval), password);
} else {
// decryption already performed above
rval = asn1.fromDer(rval);
}
if(rval !== null) {
rval = pki.privateKeyFromAsn1(rval);
}
return rval;
};
/**
* Derives a PKCS#12 key.
*
* @param password the password to derive the key material from, null or
* undefined for none.
* @param salt the salt, as a ByteBuffer, to use.
* @param id the PKCS#12 ID byte (1 = key material, 2 = IV, 3 = MAC).
* @param iter the iteration count.
* @param n the number of bytes to derive from the password.
* @param md the message digest to use, defaults to SHA-1.
*
* @return a ByteBuffer with the bytes derived from the password.
*/
pki.pbe.generatePkcs12Key = function(password, salt, id, iter, n, md) {
var j, l;
if(typeof md === 'undefined' || md === null) {
if(!('sha1' in forge.md)) {
throw new Error('"sha1" hash algorithm unavailable.');
}
md = forge.md.sha1.create();
}
var u = md.digestLength;
var v = md.blockLength;
var result = new forge.util.ByteBuffer();
/* Convert password to Unicode byte buffer + trailing 0-byte. */
var passBuf = new forge.util.ByteBuffer();
if(password !== null && password !== undefined) {
for(l = 0; l < password.length; l++) {
passBuf.putInt16(password.charCodeAt(l));
}
passBuf.putInt16(0);
}
/* Length of salt and password in BYTES. */
var p = passBuf.length();
var s = salt.length();
/* 1. Construct a string, D (the "diversifier"), by concatenating
v copies of ID. */
var D = new forge.util.ByteBuffer();
D.fillWithByte(id, v);
/* 2. Concatenate copies of the salt together to create a string S of length
v * ceil(s / v) bytes (the final copy of the salt may be trunacted
to create S).
Note that if the salt is the empty string, then so is S. */
var Slen = v * Math.ceil(s / v);
var S = new forge.util.ByteBuffer();
for(l = 0; l < Slen; l++) {
S.putByte(salt.at(l % s));
}
/* 3. Concatenate copies of the password together to create a string P of
length v * ceil(p / v) bytes (the final copy of the password may be
truncated to create P).
Note that if the password is the empty string, then so is P. */
var Plen = v * Math.ceil(p / v);
var P = new forge.util.ByteBuffer();
for(l = 0; l < Plen; l++) {
P.putByte(passBuf.at(l % p));
}
/* 4. Set I=S||P to be the concatenation of S and P. */
var I = S;
I.putBuffer(P);
/* 5. Set c=ceil(n / u). */
var c = Math.ceil(n / u);
/* 6. For i=1, 2, ..., c, do the following: */
for(var i = 1; i <= c; i++) {
/* a) Set Ai=H^r(D||I). (l.e. the rth hash of D||I, H(H(H(...H(D||I)))) */
var buf = new forge.util.ByteBuffer();
buf.putBytes(D.bytes());
buf.putBytes(I.bytes());
for(var round = 0; round < iter; round++) {
md.start();
md.update(buf.getBytes());
buf = md.digest();
}
/* b) Concatenate copies of Ai to create a string B of length v bytes (the
final copy of Ai may be truncated to create B). */
var B = new forge.util.ByteBuffer();
for(l = 0; l < v; l++) {
B.putByte(buf.at(l % u));
}
/* c) Treating I as a concatenation I0, I1, ..., Ik-1 of v-byte blocks,
where k=ceil(s / v) + ceil(p / v), modify I by setting
Ij=(Ij+B+1) mod 2v for each j. */
var k = Math.ceil(s / v) + Math.ceil(p / v);
var Inew = new forge.util.ByteBuffer();
for(j = 0; j < k; j++) {
var chunk = new forge.util.ByteBuffer(I.getBytes(v));
var x = 0x1ff;
for(l = B.length() - 1; l >= 0; l--) {
x = x >> 8;
x += B.at(l) + chunk.at(l);
chunk.setAt(l, x & 0xff);
}
Inew.putBuffer(chunk);
}
I = Inew;
/* Add Ai to A. */
result.putBuffer(buf);
}
result.truncate(result.length() - n);
return result;
};
/**
* Get new Forge cipher object instance.
*
* @param oid the OID (in string notation).
* @param params the ASN.1 params object.
* @param password the password to decrypt with.
*
* @return new cipher object instance.
*/
pki.pbe.getCipher = function(oid, params, password) {
switch(oid) {
case pki.oids['pkcs5PBES2']:
return pki.pbe.getCipherForPBES2(oid, params, password);
case pki.oids['pbeWithSHAAnd3-KeyTripleDES-CBC']:
case pki.oids['pbewithSHAAnd40BitRC2-CBC']:
return pki.pbe.getCipherForPKCS12PBE(oid, params, password);
default:
var error = new Error('Cannot read encrypted PBE data block. Unsupported OID.');
error.oid = oid;
error.supportedOids = [
'pkcs5PBES2',
'pbeWithSHAAnd3-KeyTripleDES-CBC',
'pbewithSHAAnd40BitRC2-CBC'
];
throw error;
}
};
/**
* Get new Forge cipher object instance according to PBES2 params block.
*
* The returned cipher instance is already started using the IV
* from PBES2 parameter block.
*
* @param oid the PKCS#5 PBKDF2 OID (in string notation).
* @param params the ASN.1 PBES2-params object.
* @param password the password to decrypt with.
*
* @return new cipher object instance.
*/
pki.pbe.getCipherForPBES2 = function(oid, params, password) {
// get PBE params
var capture = {};
var errors = [];
if(!asn1.validate(params, PBES2AlgorithmsValidator, capture, errors)) {
var error = new Error('Cannot read password-based-encryption algorithm ' +
'parameters. ASN.1 object is not a supported EncryptedPrivateKeyInfo.');
error.errors = errors;
throw error;
}
// check oids
oid = asn1.derToOid(capture.kdfOid);
if(oid !== pki.oids['pkcs5PBKDF2']) {
var error = new Error('Cannot read encrypted private key. ' +
'Unsupported key derivation function OID.');
error.oid = oid;
error.supportedOids = ['pkcs5PBKDF2'];
throw error;
}
oid = asn1.derToOid(capture.encOid);
if(oid !== pki.oids['aes128-CBC'] &&
oid !== pki.oids['aes192-CBC'] &&
oid !== pki.oids['aes256-CBC'] &&
oid !== pki.oids['des-EDE3-CBC'] &&
oid !== pki.oids['desCBC']) {
var error = new Error('Cannot read encrypted private key. ' +
'Unsupported encryption scheme OID.');
error.oid = oid;
error.supportedOids = [
'aes128-CBC', 'aes192-CBC', 'aes256-CBC', 'des-EDE3-CBC', 'desCBC'];
throw error;
}
// set PBE params
var salt = capture.kdfSalt;
var count = forge.util.createBuffer(capture.kdfIterationCount);
count = count.getInt(count.length() << 3);
var dkLen;
var cipherFn;
switch(pki.oids[oid]) {
case 'aes128-CBC':
dkLen = 16;
cipherFn = forge.aes.createDecryptionCipher;
break;
case 'aes192-CBC':
dkLen = 24;
cipherFn = forge.aes.createDecryptionCipher;
break;
case 'aes256-CBC':
dkLen = 32;
cipherFn = forge.aes.createDecryptionCipher;
break;
case 'des-EDE3-CBC':
dkLen = 24;
cipherFn = forge.des.createDecryptionCipher;
break;
case 'desCBC':
dkLen = 8;
cipherFn = forge.des.createDecryptionCipher;
break;
}
// get PRF message digest
var md = prfOidToMessageDigest(capture.prfOid);
// decrypt private key using pbe with chosen PRF and AES/DES
var dk = forge.pkcs5.pbkdf2(password, salt, count, dkLen, md);
var iv = capture.encIv;
var cipher = cipherFn(dk);
cipher.start(iv);
return cipher;
};
/**
* Get new Forge cipher object instance for PKCS#12 PBE.
*
* The returned cipher instance is already started using the key & IV
* derived from the provided password and PKCS#12 PBE salt.
*
* @param oid The PKCS#12 PBE OID (in string notation).
* @param params The ASN.1 PKCS#12 PBE-params object.
* @param password The password to decrypt with.
*
* @return the new cipher object instance.
*/
pki.pbe.getCipherForPKCS12PBE = function(oid, params, password) {
// get PBE params
var capture = {};
var errors = [];
if(!asn1.validate(params, pkcs12PbeParamsValidator, capture, errors)) {
var error = new Error('Cannot read password-based-encryption algorithm ' +
'parameters. ASN.1 object is not a supported EncryptedPrivateKeyInfo.');
error.errors = errors;
throw error;
}
var salt = forge.util.createBuffer(capture.salt);
var count = forge.util.createBuffer(capture.iterations);
count = count.getInt(count.length() << 3);
var dkLen, dIvLen, cipherFn;
switch(oid) {
case pki.oids['pbeWithSHAAnd3-KeyTripleDES-CBC']:
dkLen = 24;
dIvLen = 8;
cipherFn = forge.des.startDecrypting;
break;
case pki.oids['pbewithSHAAnd40BitRC2-CBC']:
dkLen = 5;
dIvLen = 8;
cipherFn = function(key, iv) {
var cipher = forge.rc2.createDecryptionCipher(key, 40);
cipher.start(iv, null);
return cipher;
};
break;
default:
var error = new Error('Cannot read PKCS #12 PBE data block. Unsupported OID.');
error.oid = oid;
throw error;
}
// get PRF message digest
var md = prfOidToMessageDigest(capture.prfOid);
var key = pki.pbe.generatePkcs12Key(password, salt, 1, count, dkLen, md);
md.start();
var iv = pki.pbe.generatePkcs12Key(password, salt, 2, count, dIvLen, md);
return cipherFn(key, iv);
};
/**
* OpenSSL's legacy key derivation function.
*
* See: http://www.openssl.org/docs/crypto/EVP_BytesToKey.html
*
* @param password the password to derive the key from.
* @param salt the salt to use, null for none.
* @param dkLen the number of bytes needed for the derived key.
* @param [options] the options to use:
* [md] an optional message digest object to use.
*/
pki.pbe.opensslDeriveBytes = function(password, salt, dkLen, md) {
if(typeof md === 'undefined' || md === null) {
if(!('md5' in forge.md)) {
throw new Error('"md5" hash algorithm unavailable.');
}
md = forge.md.md5.create();
}
if(salt === null) {
salt = '';
}
var digests = [hash(md, password + salt)];
for(var length = 16, i = 1; length < dkLen; ++i, length += 16) {
digests.push(hash(md, digests[i - 1] + password + salt));
}
return digests.join('').substr(0, dkLen);
};
function hash(md, bytes) {
return md.start().update(bytes).digest().getBytes();
}
function prfOidToMessageDigest(prfOid) {
// get PRF algorithm, default to SHA-1
var prfAlgorithm;
if(!prfOid) {
prfAlgorithm = 'hmacWithSHA1';
} else {
prfAlgorithm = pki.oids[asn1.derToOid(prfOid)];
if(!prfAlgorithm) {
var error = new Error('Unsupported PRF OID.');
error.oid = prfOid;
error.supported = [
'hmacWithSHA1', 'hmacWithSHA224', 'hmacWithSHA256', 'hmacWithSHA384',
'hmacWithSHA512'];
throw error;
}
}
return prfAlgorithmToMessageDigest(prfAlgorithm);
}
function prfAlgorithmToMessageDigest(prfAlgorithm) {
var factory = forge.md;
switch(prfAlgorithm) {
case 'hmacWithSHA224':
factory = forge.md.sha512;
case 'hmacWithSHA1':
case 'hmacWithSHA256':
case 'hmacWithSHA384':
case 'hmacWithSHA512':
prfAlgorithm = prfAlgorithm.substr(8).toLowerCase();
break;
default:
var error = new Error('Unsupported PRF algorithm.');
error.algorithm = prfAlgorithm;
error.supported = [
'hmacWithSHA1', 'hmacWithSHA224', 'hmacWithSHA256', 'hmacWithSHA384',
'hmacWithSHA512'];
throw error;
}
if(!factory || !(prfAlgorithm in factory)) {
throw new Error('Unknown hash algorithm: ' + prfAlgorithm);
}
return factory[prfAlgorithm].create();
}
function createPbkdf2Params(salt, countBytes, dkLen, prfAlgorithm) {
var params = asn1.create(asn1.Class.UNIVERSAL, asn1.Type.SEQUENCE, true, [
// salt
asn1.create(
asn1.Class.UNIVERSAL, asn1.Type.OCTETSTRING, false, salt),
// iteration count
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.INTEGER, false,
countBytes.getBytes())
]);
// when PRF algorithm is not SHA-1 default, add key length and PRF algorithm
if(prfAlgorithm !== 'hmacWithSHA1') {
params.value.push(
// key length
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.INTEGER, false,
forge.util.hexToBytes(dkLen.toString(16))),
// AlgorithmIdentifier
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.SEQUENCE, true, [
// algorithm
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.OID, false,
asn1.oidToDer(pki.oids[prfAlgorithm]).getBytes()),
// parameters (null)
asn1.create(asn1.Class.UNIVERSAL, asn1.Type.NULL, false, '')
]));
}
return params;
}