// GPG4Browsers - An OpenPGP implementation in javascript
// Copyright (C) 2011 Recurity Labs GmbH
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
// The GPG4Browsers crypto interface
/**
* @requires crypto/cipher
* @requires crypto/public_key
* @requires crypto/random
* @requires type/mpi
* @module crypto/crypto
*/
var random = require('./random.js'),
cipher = require('./cipher'),
publicKey = require('./public_key'),
type_mpi = require('../type/mpi.js');
module.exports = {
/**
* Encrypts data using the specified public key multiprecision integers
* and the specified algorithm.
* @param {module:enums.publicKey} algo Algorithm to be used (See {@link http://tools.ietf.org/html/rfc4880#section-9.1|RFC 4880 9.1})
* @param {Array<module:type/mpi>} publicMPIs Algorithm dependent multiprecision integers
* @param {module:type/mpi} data Data to be encrypted as MPI
* @return {Array<module:type/mpi>} if RSA an module:type/mpi;
* if elgamal encryption an array of two module:type/mpi is returned; otherwise null
*/
publicKeyEncrypt: function(algo, publicMPIs, data) {
var result = (function() {
var m;
switch (algo) {
case 'rsa_encrypt':
case 'rsa_encrypt_sign':
var rsa = new publicKey.rsa();
var n = publicMPIs[0].toBigInteger();
var e = publicMPIs[1].toBigInteger();
m = data.toBigInteger();
return [rsa.encrypt(m, e, n)];
case 'elgamal':
var elgamal = new publicKey.elgamal();
var p = publicMPIs[0].toBigInteger();
var g = publicMPIs[1].toBigInteger();
var y = publicMPIs[2].toBigInteger();
m = data.toBigInteger();
return elgamal.encrypt(m, g, p, y);
default:
return [];
}
})();
return result.map(function(bn) {
var mpi = new type_mpi();
mpi.fromBigInteger(bn);
return mpi;
});
},
/**
* Decrypts data using the specified public key multiprecision integers of the private key,
* the specified secretMPIs of the private key and the specified algorithm.
* @param {module:enums.publicKey} algo Algorithm to be used (See {@link http://tools.ietf.org/html/rfc4880#section-9.1|RFC 4880 9.1})
* @param {Array<module:type/mpi>} publicMPIs Algorithm dependent multiprecision integers
* of the public key part of the private key
* @param {Array<module:type/mpi>} secretMPIs Algorithm dependent multiprecision integers
* of the private key used
* @param {module:type/mpi} data Data to be encrypted as MPI
* @return {module:type/mpi} returns a big integer containing the decrypted data; otherwise null
*/
publicKeyDecrypt: function(algo, keyIntegers, dataIntegers) {
var p;
var bn = (function() {
switch (algo) {
case 'rsa_encrypt_sign':
case 'rsa_encrypt':
var rsa = new publicKey.rsa();
// 0 and 1 are the public key.
var d = keyIntegers[2].toBigInteger();
p = keyIntegers[3].toBigInteger();
var q = keyIntegers[4].toBigInteger();
var u = keyIntegers[5].toBigInteger();
var m = dataIntegers[0].toBigInteger();
return rsa.decrypt(m, d, p, q, u);
case 'elgamal':
var elgamal = new publicKey.elgamal();
var x = keyIntegers[3].toBigInteger();
var c1 = dataIntegers[0].toBigInteger();
var c2 = dataIntegers[1].toBigInteger();
p = keyIntegers[0].toBigInteger();
return elgamal.decrypt(c1, c2, p, x);
default:
return null;
}
})();
var result = new type_mpi();
result.fromBigInteger(bn);
return result;
},
/** Returns the number of integers comprising the private key of an algorithm
* @param {String} algo The public key algorithm
* @return {Integer} The number of integers.
*/
getPrivateMpiCount: function(algo) {
switch (algo) {
case 'rsa_encrypt':
case 'rsa_encrypt_sign':
case 'rsa_sign':
// Algorithm-Specific Fields for RSA secret keys:
// - multiprecision integer (MPI) of RSA secret exponent d.
// - MPI of RSA secret prime value p.
// - MPI of RSA secret prime value q (p < q).
// - MPI of u, the multiplicative inverse of p, mod q.
return 4;
case 'elgamal':
// Algorithm-Specific Fields for Elgamal secret keys:
// - MPI of Elgamal secret exponent x.
return 1;
case 'dsa':
// Algorithm-Specific Fields for DSA secret keys:
// - MPI of DSA secret exponent x.
return 1;
default:
throw new Error('Unknown algorithm');
}
},
getPublicMpiCount: function(algo) {
// - A series of multiprecision integers comprising the key material:
// Algorithm-Specific Fields for RSA public keys:
// - a multiprecision integer (MPI) of RSA public modulus n;
// - an MPI of RSA public encryption exponent e.
switch (algo) {
case 'rsa_encrypt':
case 'rsa_encrypt_sign':
case 'rsa_sign':
return 2;
// Algorithm-Specific Fields for Elgamal public keys:
// - MPI of Elgamal prime p;
// - MPI of Elgamal group generator g;
// - MPI of Elgamal public key value y (= g**x mod p where x is secret).
case 'elgamal':
return 3;
// Algorithm-Specific Fields for DSA public keys:
// - MPI of DSA prime p;
// - MPI of DSA group order q (q is a prime divisor of p-1);
// - MPI of DSA group generator g;
// - MPI of DSA public-key value y (= g**x mod p where x is secret).
case 'dsa':
return 4;
default:
throw new Error('Unknown algorithm.');
}
},
generateMpi: function(algo, bits) {
var result = (function() {
switch (algo) {
case 'rsa_encrypt':
case 'rsa_encrypt_sign':
case 'rsa_sign':
//remember "publicKey" refers to the crypto/public_key dir
var rsa = new publicKey.rsa();
var keyObject = rsa.generate(bits, "10001");
var output = [];
output.push(keyObject.n);
output.push(keyObject.ee);
output.push(keyObject.d);
output.push(keyObject.p);
output.push(keyObject.q);
output.push(keyObject.u);
return output;
default:
throw new Error('Unsupported algorithm for key generation.');
}
})();
return result.map(function(bn) {
var mpi = new type_mpi();
mpi.fromBigInteger(bn);
return mpi;
});
},
/**
* generate random byte prefix as string for the specified algorithm
* @param {module:enums.symmetric} algo Algorithm to use (see {@link http://tools.ietf.org/html/rfc4880#section-9.2|RFC 4880 9.2})
* @return {String} Random bytes with length equal to the block
* size of the cipher
*/
getPrefixRandom: function(algo) {
return random.getRandomBytes(cipher[algo].blockSize);
},
/**
* Generating a session key for the specified symmetric algorithm
* @param {module:enums.symmetric} algo Algorithm to use (see {@link http://tools.ietf.org/html/rfc4880#section-9.2|RFC 4880 9.2})
* @return {String} Random bytes as a string to be used as a key
*/
generateSessionKey: function(algo) {
return random.getRandomBytes(cipher[algo].keySize);
}
};