chushihua

node_modules/elliptic/lib/elliptic/eddsa/index.js

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+'use strict';
+
+var hash = require('hash.js');
+var curves = require('../curves');
+var utils = require('../utils');
+var assert = utils.assert;
+var parseBytes = utils.parseBytes;
+var KeyPair = require('./key');
+var Signature = require('./signature');
+
+function EDDSA(curve) {
+  assert(curve === 'ed25519', 'only tested with ed25519 so far');
+
+  if (!(this instanceof EDDSA))
+    return new EDDSA(curve);
+
+  curve = curves[curve].curve;
+  this.curve = curve;
+  this.g = curve.g;
+  this.g.precompute(curve.n.bitLength() + 1);
+
+  this.pointClass = curve.point().constructor;
+  this.encodingLength = Math.ceil(curve.n.bitLength() / 8);
+  this.hash = hash.sha512;
+}
+
+module.exports = EDDSA;
+
+/**
+* @param {Array|String} message - message bytes
+* @param {Array|String|KeyPair} secret - secret bytes or a keypair
+* @returns {Signature} - signature
+*/
+EDDSA.prototype.sign = function sign(message, secret) {
+  message = parseBytes(message);
+  var key = this.keyFromSecret(secret);
+  var r = this.hashInt(key.messagePrefix(), message);
+  var R = this.g.mul(r);
+  var Rencoded = this.encodePoint(R);
+  var s_ = this.hashInt(Rencoded, key.pubBytes(), message)
+    .mul(key.priv());
+  var S = r.add(s_).umod(this.curve.n);
+  return this.makeSignature({ R: R, S: S, Rencoded: Rencoded });
+};
+
+/**
+* @param {Array} message - message bytes
+* @param {Array|String|Signature} sig - sig bytes
+* @param {Array|String|Point|KeyPair} pub - public key
+* @returns {Boolean} - true if public key matches sig of message
+*/
+EDDSA.prototype.verify = function verify(message, sig, pub) {
+  message = parseBytes(message);
+  sig = this.makeSignature(sig);
+  var key = this.keyFromPublic(pub);
+  var h = this.hashInt(sig.Rencoded(), key.pubBytes(), message);
+  var SG = this.g.mul(sig.S());
+  var RplusAh = sig.R().add(key.pub().mul(h));
+  return RplusAh.eq(SG);
+};
+
+EDDSA.prototype.hashInt = function hashInt() {
+  var hash = this.hash();
+  for (var i = 0; i < arguments.length; i++)
+    hash.update(arguments[i]);
+  return utils.intFromLE(hash.digest()).umod(this.curve.n);
+};
+
+EDDSA.prototype.keyFromPublic = function keyFromPublic(pub) {
+  return KeyPair.fromPublic(this, pub);
+};
+
+EDDSA.prototype.keyFromSecret = function keyFromSecret(secret) {
+  return KeyPair.fromSecret(this, secret);
+};
+
+EDDSA.prototype.makeSignature = function makeSignature(sig) {
+  if (sig instanceof Signature)
+    return sig;
+  return new Signature(this, sig);
+};
+
+/**
+* * https://tools.ietf.org/html/draft-josefsson-eddsa-ed25519-03#section-5.2
+*
+* EDDSA defines methods for encoding and decoding points and integers. These are
+* helper convenience methods, that pass along to utility functions implied
+* parameters.
+*
+*/
+EDDSA.prototype.encodePoint = function encodePoint(point) {
+  var enc = point.getY().toArray('le', this.encodingLength);
+  enc[this.encodingLength - 1] |= point.getX().isOdd() ? 0x80 : 0;
+  return enc;
+};
+
+EDDSA.prototype.decodePoint = function decodePoint(bytes) {
+  bytes = utils.parseBytes(bytes);
+
+  var lastIx = bytes.length - 1;
+  var normed = bytes.slice(0, lastIx).concat(bytes[lastIx] & ~0x80);
+  var xIsOdd = (bytes[lastIx] & 0x80) !== 0;
+
+  var y = utils.intFromLE(normed);
+  return this.curve.pointFromY(y, xIsOdd);
+};
+
+EDDSA.prototype.encodeInt = function encodeInt(num) {
+  return num.toArray('le', this.encodingLength);
+};
+
+EDDSA.prototype.decodeInt = function decodeInt(bytes) {
+  return utils.intFromLE(bytes);
+};
+
+EDDSA.prototype.isPoint = function isPoint(val) {
+  return val instanceof this.pointClass;
+};