72 lines
1.8 KiB
JavaScript
72 lines
1.8 KiB
JavaScript
'use strict';
|
|
|
|
var BN = require('./bn');
|
|
var elliptic = require('elliptic');
|
|
|
|
var ec = elliptic.curves.secp256k1;
|
|
var ecpoint = ec.curve.point.bind(ec.curve);
|
|
var p = ec.curve.point();
|
|
|
|
var bufferUtil = require('../util/buffer');
|
|
|
|
var Point = function Point(x, y, isRed) {
|
|
return ecpoint(x, y, isRed);
|
|
};
|
|
|
|
Point.prototype = Object.getPrototypeOf(p);
|
|
|
|
Point.fromX = ec.curve.pointFromX.bind(ec.curve);
|
|
|
|
Point.getG = function() {
|
|
var p = Point(ec.curve.g.getX(), ec.curve.g.getY());
|
|
return p;
|
|
};
|
|
|
|
Point.getN = function() {
|
|
return BN(ec.curve.n.toArray());
|
|
};
|
|
|
|
Point.prototype._getX = Point.prototype.getX;
|
|
Point.prototype.getX = function() {
|
|
return BN(this._getX().toArray());
|
|
};
|
|
|
|
Point.prototype._getY = Point.prototype.getY;
|
|
Point.prototype.getY = function() {
|
|
return BN(this._getY().toArray());
|
|
};
|
|
|
|
//https://www.iacr.org/archive/pkc2003/25670211/25670211.pdf
|
|
Point.prototype.validate = function() {
|
|
/* jshint maxcomplexity: 8 */
|
|
var p2 = Point.fromX(this.getY().isOdd(), this.getX());
|
|
if (p2.y.cmp(this.y) !== 0) {
|
|
throw new Error('Invalid y value of public key');
|
|
}
|
|
var xValidRange = (this.getX().gt(-1) && this.getX().lt(Point.getN()));
|
|
var yValidRange = (this.getY().gt(-1) && this.getY().lt(Point.getN()));
|
|
if (!(xValidRange && yValidRange)) {
|
|
throw new Error('Point does not lie on the curve');
|
|
}
|
|
if (!(this.mul(Point.getN()).isInfinity())) {
|
|
throw new Error('Point times N must be infinity');
|
|
}
|
|
return this;
|
|
};
|
|
|
|
Point.pointToCompressed = function pointToCompressed(point) {
|
|
var xbuf = point.getX().toBuffer({size: 32});
|
|
var ybuf = point.getY().toBuffer({size: 32});
|
|
|
|
var prefix;
|
|
var odd = ybuf[ybuf.length - 1] % 2;
|
|
if (odd) {
|
|
prefix = new Buffer([0x03]);
|
|
} else {
|
|
prefix = new Buffer([0x02]);
|
|
}
|
|
return bufferUtil.concat([prefix, xbuf]);
|
|
};
|
|
|
|
module.exports = Point;
|