87 lines
2.3 KiB
JavaScript
87 lines
2.3 KiB
JavaScript
var Point = require('./point');
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var bn = require('./bn');
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var Pubkey = function Pubkey(point) {
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if (!(this instanceof Pubkey))
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return new Pubkey(point);
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if (point && !point.getX() && !point.getY())
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throw new Error('pubkey: Invalid point');
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this.point = point;
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};
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Pubkey.prototype.fromDER = function(buf) {
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if (buf[0] == 0x04) {
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var xbuf = buf.slice(1, 33);
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var ybuf = buf.slice(33, 65);
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if (xbuf.length !== 32 || ybuf.length !== 32 || buf.length !== 65)
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throw new Error('pubkey: Length of x and y must be 32 bytes');
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var x = bn(xbuf);
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var y = bn(ybuf);
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this.point = Point(x, y);
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} else if (buf[0] == 0x03) {
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var xbuf = buf.slice(1);
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var x = bn(xbuf);
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this.fromX(true, x);
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} else if (buf[0] == 0x02) {
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var xbuf = buf.slice(1);
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var x = bn(xbuf);
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this.fromX(false, x);
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} else {
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throw new Error('pubkey: Invalid DER format pubkey');
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}
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return this;
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};
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Pubkey.prototype.fromString = function(str) {
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this.fromDER(new Buffer(str, 'hex'));
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};
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Pubkey.prototype.fromX = function(odd, x) {
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if (typeof odd !== 'boolean')
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throw new Error('pubkey: Must specify whether y is odd or not (true or false)');
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this.point = Point.fromX(odd, x);
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};
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Pubkey.prototype.toBuffer = function() {
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return this.toDER(true);
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};
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Pubkey.prototype.toDER = function(compressed) {
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if (typeof compressed !== 'boolean')
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throw new Error('pubkey: Must specify whether the public key is compressed or not (true or false)');
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var x = this.point.getX();
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var y = this.point.getY();
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var xbuf = x.toBuffer({size: 32});
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var ybuf = y.toBuffer({size: 32});
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if (!compressed) {
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var prefix = new Buffer([0x04]);
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return Buffer.concat([prefix, xbuf, ybuf]);
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} else {
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var odd = ybuf[ybuf.length - 1] % 2;
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if (odd)
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var prefix = new Buffer([0x03]);
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else
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var prefix = new Buffer([0x02]);
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return Buffer.concat([prefix, xbuf]);
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}
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};
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Pubkey.prototype.toString = function() {
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return this.toDER(true).toString('hex');
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};
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//https://www.iacr.org/archive/pkc2003/25670211/25670211.pdf
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Pubkey.prototype.validate = function() {
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if (this.point.isInfinity())
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throw new Error('point: Point cannot be equal to Infinity');
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if (this.point.eq(Point(bn(0), bn(0))))
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throw new Error('point: Point cannot be equal to 0, 0');
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this.point.validate();
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return this;
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};
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module.exports = Pubkey;
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