fork-openpgpjs/src/ciphers/asymmetric/rsa.js

136 lines
4.0 KiB
JavaScript

// 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
//
// RSA implementation
function SecureRandom(){
function nextBytes(byteArray){
for(var n = 0; n < byteArray.length;n++){
byteArray[n] = openpgp_crypto_getSecureRandomOctet();
}
}
this.nextBytes = nextBytes;
}
function RSA() {
/**
* This function uses jsbn Big Num library to decrypt RSA
* @param m
* message
* @param d
* RSA d as BigInteger
* @param p
* RSA p as BigInteger
* @param q
* RSA q as BigInteger
* @param u
* RSA u as BigInteger
* @return
*/
function decrypt(m, d, p, q, u) {
var xp = m.mod(p).modPow(d.mod(p.subtract(BigInteger.ONE)), p);
var xq = m.mod(q).modPow(d.mod(q.subtract(BigInteger.ONE)), q);
util.print_debug("rsa.js decrypt\nxpn:"+util.hexstrdump(xp.toMPI())+"\nxqn:"+util.hexstrdump(xq.toMPI()));
var t = xq.subtract(xp);
if (t[0] == 0) {
t = xp.subtract(xq);
t = t.multiply(u).mod(q);
t = q.subtract(t);
} else {
t = t.multiply(u).mod(q);
}
return t.multiply(p).add(xp);
}
/**
* encrypt message
* @param m message as BigInteger
* @param e public MPI part as BigInteger
* @param n public MPI part as BigInteger
* @return BigInteger
*/
function encrypt(m,e,n) {
return m.modPowInt(e, n);
}
/* Sign and Verify */
function sign(m,d,n) {
return m.modPow(d, n);
}
function verify(x,e,n) {
return x.modPowInt(e, n);
}
// "empty" RSA key constructor
function keyObject() {
this.n = null;
this.e = 0;
this.ee = null;
this.d = null;
this.p = null;
this.q = null;
this.dmp1 = null;
this.dmq1 = null;
this.coeff = null;
}
// Generate a new random private key B bits long, using public expt E
function generate(B,E) {
var key = new keyObject();
var rng = new SecureRandom();
var qs = B>>1;
key.e = parseInt(E,16);
key.ee = new BigInteger(E,16);
for(;;) {
for(;;) {
key.p = new BigInteger(B-qs,1,rng);
if(key.p.subtract(BigInteger.ONE).gcd(key.ee).compareTo(BigInteger.ONE) == 0 && key.p.isProbablePrime(10)) break;
}
for(;;) {
key.q = new BigInteger(qs,1,rng);
if(key.q.subtract(BigInteger.ONE).gcd(key.ee).compareTo(BigInteger.ONE) == 0 && key.q.isProbablePrime(10)) break;
}
if(key.p.compareTo(key.q) <= 0) {
var t = key.p;
key.p = key.q;
key.q = t;
}
var p1 = key.p.subtract(BigInteger.ONE);
var q1 = key.q.subtract(BigInteger.ONE);
var phi = p1.multiply(q1);
if(phi.gcd(key.ee).compareTo(BigInteger.ONE) == 0) {
key.n = key.p.multiply(key.q);
key.d = key.ee.modInverse(phi);
key.dmp1 = key.d.mod(p1);
key.dmq1 = key.d.mod(q1);
key.coeff = key.q.modInverse(key.p);
break;
}
}
return key;
}
this.encrypt = encrypt;
this.decrypt = decrypt;
this.verify = verify;
this.sign = sign;
this.generate = generate;
this.keyObject = keyObject;
}