'use strict';
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var BN = require('bn.js');
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var utils = require('../utils');
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var assert = utils.assert;
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function Signature(options, enc) {
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if (options instanceof Signature)
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return options;
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if (this._importDER(options, enc))
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return;
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assert(options.r && options.s, 'Signature without r or s');
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this.r = new BN(options.r, 16);
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this.s = new BN(options.s, 16);
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if (options.recoveryParam === undefined)
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this.recoveryParam = null;
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else
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this.recoveryParam = options.recoveryParam;
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}
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module.exports = Signature;
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function Position() {
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this.place = 0;
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}
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function getLength(buf, p) {
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var initial = buf[p.place++];
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if (!(initial & 0x80)) {
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return initial;
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}
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var octetLen = initial & 0xf;
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// Indefinite length or overflow
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if (octetLen === 0 || octetLen > 4) {
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return false;
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}
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var val = 0;
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for (var i = 0, off = p.place; i < octetLen; i++, off++) {
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val <<= 8;
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val |= buf[off];
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val >>>= 0;
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}
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// Leading zeroes
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if (val <= 0x7f) {
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return false;
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}
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p.place = off;
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return val;
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}
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function rmPadding(buf) {
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var i = 0;
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var len = buf.length - 1;
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while (!buf[i] && !(buf[i + 1] & 0x80) && i < len) {
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i++;
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}
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if (i === 0) {
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return buf;
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}
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return buf.slice(i);
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}
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Signature.prototype._importDER = function _importDER(data, enc) {
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data = utils.toArray(data, enc);
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var p = new Position();
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if (data[p.place++] !== 0x30) {
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return false;
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}
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var len = getLength(data, p);
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if (len === false) {
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return false;
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}
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if ((len + p.place) !== data.length) {
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return false;
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}
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if (data[p.place++] !== 0x02) {
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return false;
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}
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var rlen = getLength(data, p);
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if (rlen === false) {
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return false;
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}
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var r = data.slice(p.place, rlen + p.place);
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p.place += rlen;
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if (data[p.place++] !== 0x02) {
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return false;
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}
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var slen = getLength(data, p);
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if (slen === false) {
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return false;
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}
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if (data.length !== slen + p.place) {
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return false;
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}
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var s = data.slice(p.place, slen + p.place);
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if (r[0] === 0) {
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if (r[1] & 0x80) {
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r = r.slice(1);
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} else {
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// Leading zeroes
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return false;
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}
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}
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if (s[0] === 0) {
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if (s[1] & 0x80) {
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s = s.slice(1);
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} else {
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// Leading zeroes
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return false;
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}
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}
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this.r = new BN(r);
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this.s = new BN(s);
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this.recoveryParam = null;
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return true;
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};
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function constructLength(arr, len) {
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if (len < 0x80) {
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arr.push(len);
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return;
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}
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var octets = 1 + (Math.log(len) / Math.LN2 >>> 3);
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arr.push(octets | 0x80);
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while (--octets) {
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arr.push((len >>> (octets << 3)) & 0xff);
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}
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arr.push(len);
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}
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Signature.prototype.toDER = function toDER(enc) {
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var r = this.r.toArray();
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var s = this.s.toArray();
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// Pad values
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if (r[0] & 0x80)
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r = [ 0 ].concat(r);
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// Pad values
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if (s[0] & 0x80)
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s = [ 0 ].concat(s);
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r = rmPadding(r);
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s = rmPadding(s);
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while (!s[0] && !(s[1] & 0x80)) {
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s = s.slice(1);
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}
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var arr = [ 0x02 ];
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constructLength(arr, r.length);
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arr = arr.concat(r);
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arr.push(0x02);
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constructLength(arr, s.length);
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var backHalf = arr.concat(s);
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var res = [ 0x30 ];
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constructLength(res, backHalf.length);
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res = res.concat(backHalf);
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return utils.encode(res, enc);
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};
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