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author | Florian Dold <florian.dold@gmail.com> | 2017-05-03 15:35:00 +0200 |
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committer | Florian Dold <florian.dold@gmail.com> | 2017-05-03 15:35:00 +0200 |
commit | de98e0b232509d5f40c135d540a70e415272ff85 (patch) | |
tree | a79222a5b58484ab3b80d18efcaaa7ccc4769b33 /node_modules/miller-rabin/lib | |
parent | e0c9d480a73fa629c1e4a47d3e721f1d2d345406 (diff) | |
download | wallet-core-de98e0b232509d5f40c135d540a70e415272ff85.tar.xz |
node_modules
Diffstat (limited to 'node_modules/miller-rabin/lib')
-rw-r--r-- | node_modules/miller-rabin/lib/mr.js | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/node_modules/miller-rabin/lib/mr.js b/node_modules/miller-rabin/lib/mr.js new file mode 100644 index 000000000..a9e935b1b --- /dev/null +++ b/node_modules/miller-rabin/lib/mr.js @@ -0,0 +1,113 @@ +var bn = require('bn.js'); +var brorand = require('brorand'); + +function MillerRabin(rand) { + this.rand = rand || new brorand.Rand(); +} +module.exports = MillerRabin; + +MillerRabin.create = function create(rand) { + return new MillerRabin(rand); +}; + +MillerRabin.prototype._rand = function _rand(n) { + var len = n.bitLength(); + var buf = this.rand.generate(Math.ceil(len / 8)); + + // Set low bits + buf[0] |= 3; + + // Mask high bits + var mask = len & 0x7; + if (mask !== 0) + buf[buf.length - 1] >>= 7 - mask; + + return new bn(buf); +} + +MillerRabin.prototype.test = function test(n, k, cb) { + var len = n.bitLength(); + var red = bn.mont(n); + var rone = new bn(1).toRed(red); + + if (!k) + k = Math.max(1, (len / 48) | 0); + + // Find d and s, (n - 1) = (2 ^ s) * d; + var n1 = n.subn(1); + var n2 = n1.subn(1); + for (var s = 0; !n1.testn(s); s++) {} + var d = n.shrn(s); + + var rn1 = n1.toRed(red); + + var prime = true; + for (; k > 0; k--) { + var a = this._rand(n2); + if (cb) + cb(a); + + var x = a.toRed(red).redPow(d); + if (x.cmp(rone) === 0 || x.cmp(rn1) === 0) + continue; + + for (var i = 1; i < s; i++) { + x = x.redSqr(); + + if (x.cmp(rone) === 0) + return false; + if (x.cmp(rn1) === 0) + break; + } + + if (i === s) + return false; + } + + return prime; +}; + +MillerRabin.prototype.getDivisor = function getDivisor(n, k) { + var len = n.bitLength(); + var red = bn.mont(n); + var rone = new bn(1).toRed(red); + + if (!k) + k = Math.max(1, (len / 48) | 0); + + // Find d and s, (n - 1) = (2 ^ s) * d; + var n1 = n.subn(1); + var n2 = n1.subn(1); + for (var s = 0; !n1.testn(s); s++) {} + var d = n.shrn(s); + + var rn1 = n1.toRed(red); + + for (; k > 0; k--) { + var a = this._rand(n2); + + var g = n.gcd(a); + if (g.cmpn(1) !== 0) + return g; + + var x = a.toRed(red).redPow(d); + if (x.cmp(rone) === 0 || x.cmp(rn1) === 0) + continue; + + for (var i = 1; i < s; i++) { + x = x.redSqr(); + + if (x.cmp(rone) === 0) + return x.fromRed().subn(1).gcd(n); + if (x.cmp(rn1) === 0) + break; + } + + if (i === s) { + x = x.redSqr(); + return x.fromRed().subn(1).gcd(n); + } + } + + return false; +}; |