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