71 lines
1.7 KiB
JavaScript
71 lines
1.7 KiB
JavaScript
"use strict";
|
|
|
|
var Key = require('./Key');
|
|
var bignum = require('bignum');
|
|
var assert = require('assert');
|
|
var elliptic = require('elliptic');
|
|
|
|
//a point on the secp256k1 curve
|
|
//x and y are bignums
|
|
var Point = function(x, y) {
|
|
this.x = x;
|
|
this.y = y;
|
|
};
|
|
|
|
Point.add = function(p1, p2) {
|
|
var ec = elliptic.curves.secp256k1;
|
|
var ecp1 = ec.curve.point(p1.x, p1.y);
|
|
var ecp2 = ec.curve.point(p2.x, p2.y);
|
|
var ecp3 = ecp1.add(ecp2);
|
|
//var p3 = ec.curve.point(ecp3.x, ecp3.y);
|
|
var p3 = new Point(ecp3.x, ecp3.y);
|
|
return p3;
|
|
};
|
|
|
|
Point.multiply = function(p1, xbuf) {
|
|
var ec = elliptic.curves.secp256k1;
|
|
var ecp1 = ec.curve.point(p1.x, p1.y);
|
|
var ecp = ecp1.mul(xbuf);
|
|
var p = new Point(ecp.x, ecp.y);
|
|
return p;
|
|
};
|
|
|
|
//convert the public key of a Key into a Point
|
|
Point.fromUncompressedPubKey = function(pubkey) {
|
|
var point = new Point();
|
|
point.x = bignum.fromBuffer((new Buffer(pubkey)).slice(1, 33), {
|
|
size: 32
|
|
});
|
|
point.y = bignum.fromBuffer((new Buffer(pubkey)).slice(33, 65), {
|
|
size: 32
|
|
});
|
|
return point;
|
|
};
|
|
|
|
//convert the Point into the Key containing a compressed public key
|
|
Point.prototype.toUncompressedPubKey = function() {
|
|
var xbuf = this.x.toBuffer({
|
|
size: 32
|
|
});
|
|
var ybuf = this.y.toBuffer({
|
|
size: 32
|
|
});
|
|
var prefix = new Buffer([0x04]);
|
|
var pub = Buffer.concat([prefix, xbuf, ybuf]);
|
|
return pub;
|
|
};
|
|
|
|
Point.prototype.toCompressedPubKey = function() {
|
|
var xbuf = this.x.toBuffer({size: 32});
|
|
var ybuf = this.y.toBuffer({size: 32});
|
|
if (ybuf[ybuf.length-1] % 2) { //odd
|
|
var pub = Buffer.concat([new Buffer([3]), xbuf]);
|
|
}
|
|
else { //even
|
|
var pub = Buffer.concat([new Buffer([2]), xbuf]);
|
|
}
|
|
return pub;
|
|
};
|
|
|
|
module.exports = (Point);
|