You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
40 lines
1.2 KiB
40 lines
1.2 KiB
var bn = require('bn.js');
|
|
var randomBytes = require('randombytes');
|
|
module.exports = crt;
|
|
function blind(priv) {
|
|
var r = getr(priv);
|
|
var blinder = r.toRed(bn.mont(priv.modulus))
|
|
.redPow(new bn(priv.publicExponent)).fromRed();
|
|
return {
|
|
blinder: blinder,
|
|
unblinder:r.invm(priv.modulus)
|
|
};
|
|
}
|
|
function crt(msg, priv) {
|
|
var blinds = blind(priv);
|
|
var len = priv.modulus.byteLength();
|
|
var mod = bn.mont(priv.modulus);
|
|
var blinded = new bn(msg).mul(blinds.blinder).umod(priv.modulus);
|
|
var c1 = blinded.toRed(bn.mont(priv.prime1));
|
|
var c2 = blinded.toRed(bn.mont(priv.prime2));
|
|
var qinv = priv.coefficient;
|
|
var p = priv.prime1;
|
|
var q = priv.prime2;
|
|
var m1 = c1.redPow(priv.exponent1);
|
|
var m2 = c2.redPow(priv.exponent2);
|
|
m1 = m1.fromRed();
|
|
m2 = m2.fromRed();
|
|
var h = m1.isub(m2).imul(qinv).umod(p);
|
|
h.imul(q);
|
|
m2.iadd(h);
|
|
return new Buffer(m2.imul(blinds.unblinder).umod(priv.modulus).toArray(false, len));
|
|
}
|
|
crt.getr = getr;
|
|
function getr(priv) {
|
|
var len = priv.modulus.byteLength();
|
|
var r = new bn(randomBytes(len));
|
|
while (r.cmp(priv.modulus) >= 0 || !r.umod(priv.prime1) || !r.umod(priv.prime2)) {
|
|
r = new bn(randomBytes(len));
|
|
}
|
|
return r;
|
|
}
|