LBRYCommunity/bitcoinjs-lib
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

ec: use signum() not equals(BigInteger.ZERO)

Browse source
This commit is contained in:
Daniel Cousens 2014-05-17 11:53:05 +10:00
parent d14b08efd1
commit d9ce4bee6b
1 changed files with 11 additions and 11 deletions

22
src/ec.js
View file

@ -94,15 +94,15 @@ function pointFpEquals(other) {
var u, v; var u, v;
// u = Y2 * Z1 - Y1 * Z2 // u = Y2 * Z1 - Y1 * Z2
u = other.y.toBigInteger().multiply(this.z).subtract(this.y.toBigInteger().multiply(other.z)).mod(this.curve.q); u = other.y.toBigInteger().multiply(this.z).subtract(this.y.toBigInteger().multiply(other.z)).mod(this.curve.q);
if(!u.equals(BigInteger.ZERO)) return false; if (u.signum() !== 0) return false;
// v = X2 * Z1 - X1 * Z2 // v = X2 * Z1 - X1 * Z2
v = other.x.toBigInteger().multiply(this.z).subtract(this.x.toBigInteger().multiply(other.z)).mod(this.curve.q); v = other.x.toBigInteger().multiply(this.z).subtract(this.x.toBigInteger().multiply(other.z)).mod(this.curve.q);
return v.equals(BigInteger.ZERO); return v.signum() === 0;
} }
function pointFpIsInfinity() { function pointFpIsInfinity() {
if((this.x == null) && (this.y == null)) return true; if ((this.x == null) && (this.y == null)) return true;
return this.z.equals(BigInteger.ZERO) && !this.y.toBigInteger().equals(BigInteger.ZERO); return this.z.signum() === 0 && this.y.toBigInteger().signum() !== 0;
} }
function pointFpNegate() { function pointFpNegate() {
@ -118,8 +118,8 @@ function pointFpAdd(b) {
// v = X2 * Z1 - X1 * Z2 // v = X2 * Z1 - X1 * Z2
var v = b.x.toBigInteger().multiply(this.z).subtract(this.x.toBigInteger().multiply(b.z)).mod(this.curve.q); var v = b.x.toBigInteger().multiply(this.z).subtract(this.x.toBigInteger().multiply(b.z)).mod(this.curve.q);
if(BigInteger.ZERO.equals(v)) { if(v.signum() === 0) {
if(BigInteger.ZERO.equals(u)) { if(u.signum() === 0) {
return this.twice(); // this == b, so double return this.twice(); // this == b, so double
} }
return this.curve.getInfinity(); // this = -b, so infinity return this.curve.getInfinity(); // this = -b, so infinity
@ -148,7 +148,7 @@ function pointFpAdd(b) {
function pointFpTwice() { function pointFpTwice() {
if(this.isInfinity()) return this; if(this.isInfinity()) return this;
if(this.y.toBigInteger().signum() == 0) return this.curve.getInfinity(); if(this.y.toBigInteger().signum() === 0) return this.curve.getInfinity();
// TODO: optimized handling of constants // TODO: optimized handling of constants
var THREE = new BigInteger("3"); var THREE = new BigInteger("3");
@ -161,7 +161,7 @@ function pointFpTwice() {
// w = 3 * x1^2 + a * z1^2 // w = 3 * x1^2 + a * z1^2
var w = x1.square().multiply(THREE); var w = x1.square().multiply(THREE);
if(!BigInteger.ZERO.equals(a)) { if(a.signum() !== 0) {
w = w.add(this.z.square().multiply(a)); w = w.add(this.z.square().multiply(a));
} }
w = w.mod(this.curve.q); w = w.mod(this.curve.q);
@ -179,7 +179,7 @@ function pointFpTwice() {
// TODO: modularize the multiplication algorithm // TODO: modularize the multiplication algorithm
function pointFpMultiply(k) { function pointFpMultiply(k) {
if(this.isInfinity()) return this; if(this.isInfinity()) return this;
if(k.signum() == 0) return this.curve.getInfinity(); if(k.signum() === 0) return this.curve.getInfinity()
var e = k; var e = k;
var h = e.multiply(new BigInteger("3")); var h = e.multiply(new BigInteger("3"));
@ -392,7 +392,7 @@ ECPointFp.prototype.add2D = function (b) {
ECPointFp.prototype.twice2D = function () { ECPointFp.prototype.twice2D = function () {
if (this.isInfinity()) return this; if (this.isInfinity()) return this;
if (this.y.toBigInteger().signum() == 0) { if (this.y.toBigInteger().signum() === 0) {
// if y1 == 0, then (x1, y1) == (x1, -y1) // if y1 == 0, then (x1, y1) == (x1, -y1)
// and hence this = -this and thus 2(x1, y1) == infinity // and hence this = -this and thus 2(x1, y1) == infinity
return this.curve.getInfinity(); return this.curve.getInfinity();
@ -410,7 +410,7 @@ ECPointFp.prototype.twice2D = function () {
ECPointFp.prototype.multiply2D = function (k) { ECPointFp.prototype.multiply2D = function (k) {
if(this.isInfinity()) return this; if(this.isInfinity()) return this;
if(k.signum() == 0) return this.curve.getInfinity(); if (k.signum() === 0) return this.curve.getInfinity()
var e = k; var e = k;
var h = e.multiply(new BigInteger("3")); var h = e.multiply(new BigInteger("3"));