137 lines
3.7 KiB
JavaScript
137 lines
3.7 KiB
JavaScript
var BN = require('./bn');
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var Point = require('./point');
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var Pubkey = require('./pubkey');
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var Signature = function Signature(r, s, i) {
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if (!(this instanceof Signature))
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return new Signature(r, s, i);
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this.r = r;
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this.s = s;
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this.i = i; //public key recovery parameter in range [0, 3]
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};
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Signature.prototype.fromCompressed = function(buf) {
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var i = buf.slice(0, 1)[0];
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var b2 = buf.slice(1, 33);
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var b3 = buf.slice(33, 65);
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if (!(i === 0 || i === 1 || i === 2 || i === 3))
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throw new Error('signature: i must be 0, 1, 2, or 3');
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if (b2.length !== 32)
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throw new Error('signature: r must be 32 bytes');
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if (b3.length !== 32)
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throw new Error('signature: s must be 32 bytes');
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this.i = i;
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this.r = BN().fromBuffer(b2);
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this.s = BN().fromBuffer(b3);
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};
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Signature.prototype.fromDER = function(buf) {
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var obj = Signature.parseDER(buf);
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this.r = obj.r;
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this.s = obj.s;
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};
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Signature.prototype.fromString = function(str) {
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var buf = new Buffer(str, 'hex');
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this.fromDER(buf);
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};
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Signature.parseDER = function(buf) {
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if (!Buffer.isBuffer(buf))
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throw new Error('signature: DER formatted signature should be a buffer');
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var header = buf[0];
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if (header !== 0x30)
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throw new Error('signature: Header byte should be 0x30');
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var length = buf[1];
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if (length !== buf.slice(2).length)
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throw new Error('signature: Length byte should length of what follows');
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var rheader = buf[2 + 0];
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if (rheader !== 0x02)
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throw new Error('signature: Integer byte for r should be 0x02');
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var rlength = buf[2 + 1];
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var rbuf = buf.slice(2 + 2, 2 + 2 + rlength);
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var r = BN().fromBuffer(rbuf);
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var rneg = buf[2 + 1 + 1] === 0x00 ? true : false;
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if (rlength !== rbuf.length)
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throw new Error('signature: Length of r incorrect');
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var sheader = buf[2 + 2 + rlength + 0];
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if (sheader !== 0x02)
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throw new Error('signature: Integer byte for s should be 0x02');
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var slength = buf[2 + 2 + rlength + 1];
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var sbuf = buf.slice(2 + 2 + rlength + 2, 2 + 2 + rlength + 2 + slength);
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var s = BN().fromBuffer(sbuf);
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var sneg = buf[2 + 2 + rlength + 2 + 2] === 0x00 ? true : false;
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if (slength !== sbuf.length)
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throw new Error('signature: Length of s incorrect');
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var sumlength = 2 + 2 + rlength + 2 + slength;
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if (length !== sumlength - 2)
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throw new Error('signature: Length of signature incorrect');
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var obj = {
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header: header,
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length: length,
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rheader: rheader,
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rlength: rlength,
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rneg: rneg,
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rbuf: rbuf,
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r: r,
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sheader: sheader,
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slength: slength,
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sneg: sneg,
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sbuf: sbuf,
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s: s
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};
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return obj;
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};
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Signature.prototype.toCompressed = function(i) {
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i = typeof i === 'number' ? i : this.i;
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if (!(i === 0 || i === 1 || i === 2 || i === 3))
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throw new Error('signature: i must be equal to 0, 1, 2, or 3');
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var b1 = new Buffer([i]);
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var b2 = this.r.toBuffer({size: 32});
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var b3 = this.s.toBuffer({size: 32});
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return Buffer.concat([b1, b2, b3]);
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};
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Signature.prototype.toDER = function() {
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var rnbuf = this.r.toBuffer();
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var snbuf = this.s.toBuffer();
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var rneg = rnbuf[0] & 0x80 ? true : false;
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var sneg = snbuf[0] & 0x80 ? true : false;
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var rbuf = rneg ? Buffer.concat([new Buffer([0x00]), rnbuf]) : rnbuf;
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var sbuf = sneg ? Buffer.concat([new Buffer([0x00]), snbuf]) : snbuf;
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var length = 2 + rbuf.length + 2 + sbuf.length;
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var rlength = rbuf.length;
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var slength = sbuf.length;
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var rheader = 0x02;
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var sheader = 0x02;
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var header = 0x30;
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var der = Buffer.concat([new Buffer([header, length, rheader, rlength]), rbuf, new Buffer([sheader, slength]), sbuf]);
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return der;
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};
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Signature.prototype.toString = function() {
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var buf = this.toDER();
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return buf.toString('hex');
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};
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module.exports = Signature;
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