add bn powermod and mulmod

This commit is contained in:
Quinn Slack 2011-04-19 05:13:45 -07:00
parent 89905acb59
commit 2bbda850b1
3 changed files with 93 additions and 0 deletions

View File

@ -275,6 +275,21 @@ sjcl.bn.prototype = {
return out; return out;
}, },
mulmod: function(x, N) {
return this.mod(N).mul(x.mod(N)).mod(N);
},
powermod: function(x, N) {
var result = new sjcl.bn(1), a = new sjcl.bn(this), k = new sjcl.bn(x);
while (true) {
if (k.limbs[0] & 1) { result = result.mulmod(a, N); }
k.halveM();
if (k.equals(0)) { break; }
a = a.mulmod(a, N);
}
return result.normalize().reduce();
},
trim: function() { trim: function() {
var l = this.limbs, p; var l = this.limbs, p;
do { do {

22
test/bn_test.js Normal file
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@ -0,0 +1,22 @@
new sjcl.test.TestCase("Bignum modular exponentiation test", function (cb) {
if (!sjcl.bn) {
this.unimplemented();
cb && cb();
return;
}
var i, tv, g, x, N, v;
for (i=0; i < sjcl.test.vector.bn_powermod.length; i++) {
tv = sjcl.test.vector.bn_powermod[i];
try {
g = new sjcl.bn(tv.g);
x = new sjcl.bn(tv.x);
N = new sjcl.bn(tv.N);
v = g.powermod(x, N);
this.require(v.equals(new sjcl.bn(tv.v)));
} catch(e) {
this.fail(e);
}
}
cb && cb();
});

56
test/bn_vectors.js Normal file
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@ -0,0 +1,56 @@
sjcl.test.vector.bn_powermod = [
{
g: 2,
x: 3,
N: 3,
v: 2
},
{
g: 2,
x: "10000000000000000000000000",
N: 1337,
v: 1206
},
{
g: 17,
x: 90,
N: 34717861147,
v: 28445204336
},
{
g: 2,
x: "0x844A000000000000000000000",
N: 13,
v: 9
},
{
g: 2,
x: 0x1010,
N: 131,
v: 59
},
{
g: 2,
x: "43207437777777877617151",
N: 13,
v: 2
},
{
g: 2,
x: "389274238947216444871600001871964319565192765874149",
N: 117,
v: 44
},
{
g: 2,
x: "89457115510016156219817846189181057618965150496979174671534084187",
N: "1897166415676096761",
v: "16840615e646a4c5c8d"
},
{
g: 2,
x: "94B7555AABE9127CC58CCF4993DB6CF84D16C124",
N: "EEAF0AB9ADB38DD69C33F80AFA8FC5E86072618775FF3C0B9EA2314C9C256576D674DF7496EA81D3383B4813D692C6E0E0D5D8E250B98BE48E495C1D6089DAD15DC7D7B46154D6B6CE8EF4AD69B15D4982559B297BCF1885C529F566660E57EC68EDBC3C05726CC02FD4CBF4976EAA9AFD5138FE8376435B9FC61D2FC0EB06E3",
v: "7E273DE8696FFC4F4E337D05B4B375BEB0DDE1569E8FA00A9886D8129BADA1F1822223CA1A605B530E379BA4729FDC59F105B4787E5186F5C671085A1447B52A48CF1970B4FB6F8400BBF4CEBFBB168152E08AB5EA53D15C1AFF87B2B9DA6E04E058AD51CC72BFC9033B564E26480D78E955A5E29E7AB245DB2BE315E2099AFB"
}
]