--- /dev/null
+"use strict";
+/**
+ * @fileOverview
+ * Digital signature scheme based on Curve25519 (Ed25519 or EdDSA).
+ */
+
+/*
+ * Copyright (c) 2011, 2012, 2014 Ron Garret
+ * Copyright (c) 2014 Mega Limited
+ * under the MIT License.
+ *
+ * Authors: Guy K. Kloss, Ron Garret
+ *
+ * You should have received a copy of the license along with this program.
+ */
+
+var core = require('./core');
+var curve255 = require('./curve255');
+var utils = require('./utils');
+var BigInteger = require('jsbn').BigInteger;
+var crypto = require('crypto');
+
+ /**
+ * @exports jodid25519/eddsa
+ * Digital signature scheme based on Curve25519 (Ed25519 or EdDSA).
+ *
+ * @description
+ * Digital signature scheme based on Curve25519 (Ed25519 or EdDSA).
+ *
+ * <p>
+ * This code is adapted from fast-djbec.js, a faster but more complicated
+ * version of the Ed25519 encryption scheme (as compared to djbec.js).
+ * It uses two different representations for big integers: The jsbn
+ * BigInteger class, which can represent arbitrary-length numbers, and a
+ * special fixed-length representation optimised for 256-bit integers.
+ * The reason both are needed is that the Ed25519 algorithm requires some
+ * 512-bit numbers.</p>
+ */
+ var ns = {};
+
+ function _bi255(value) {
+ if (!(this instanceof _bi255)) {
+ return new _bi255(value);
+ }
+ if (typeof value === 'undefined') {
+ return _ZERO;
+ }
+ var c = value.constructor;
+ if ((c === Array || c === Uint16Array || c === Uint32Array) && (value.length === 16)) {
+ this.n = value;
+ } else if ((c === Array) && (value.length === 32)) {
+ this.n = _bytes2bi255(value).n;
+ } else if (c === String) {
+ this.n = utils.hexDecode(value);
+ } else if (c === Number) {
+ this.n = [value & 0xffff,
+ value >> 16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
+ } else if (value instanceof _bi255) {
+ this.n = value.n.slice(0); // Copy constructor
+ } else {
+ throw "Bad argument for bignum: " + value;
+ }
+ }
+
+ _bi255.prototype = {
+ 'toString' : function() {
+ return utils.hexEncode(this.n);
+ },
+ 'toSource' : function() {
+ return '_' + utils.hexEncode(this.n);
+ },
+ 'plus' : function(n1) {
+ return _bi255(core.bigintadd(this.n, n1.n));
+ },
+ 'minus' : function(n1) {
+ return _bi255(core.bigintsub(this.n, n1.n)).modq();
+ },
+ 'times' : function(n1) {
+ return _bi255(core.mulmodp(this.n, n1.n));
+ },
+ 'divide' : function(n1) {
+ return this.times(n1.inv());
+ },
+ 'sqr' : function() {
+ return _bi255(core.sqrmodp(this.n));
+ },
+ 'cmp' : function(n1) {
+ return core.bigintcmp(this.n, n1.n);
+ },
+ 'equals' : function(n1) {
+ return this.cmp(n1) === 0;
+ },
+ 'isOdd' : function() {
+ return (this.n[0] & 1) === 1;
+ },
+ 'shiftLeft' : function(cnt) {
+ _shiftL(this.n, cnt);
+ return this;
+ },
+ 'shiftRight' : function(cnt) {
+ _shiftR(this.n, cnt);
+ return this;
+ },
+ 'inv' : function() {
+ return _bi255(core.invmodp(this.n));
+ },
+ 'pow' : function(e) {
+ return _bi255(_pow(this.n, e.n));
+ },
+ 'modq' : function() {
+ return _modq(this);
+ },
+ 'bytes' : function() {
+ return _bi255_bytes(this);
+ }
+ };
+
+ function _shiftL(n, cnt) {
+ var lastcarry = 0;
+ for (var i = 0; i < 16; i++) {
+ var carry = n[i] >> (16 - cnt);
+ n[i] = (n[i] << cnt) & 0xffff | lastcarry;
+ lastcarry = carry;
+ }
+ return n;
+ }
+
+ function _shiftR(n, cnt) {
+ var lastcarry = 0;
+ for (var i = 15; i >= 0; i--) {
+ var carry = n[i] << (16 - cnt) & 0xffff;
+ n[i] = (n[i] >> cnt) | lastcarry;
+ lastcarry = carry;
+ }
+ return n;
+ }
+
+ function _bi255_bytes(n) {
+ n = _bi255(n); // Make a copy because shiftRight is destructive
+ var a = new Array(32);
+ for (var i = 31; i >= 0; i--) {
+ a[i] = n.n[0] & 0xff;
+ n.shiftRight(8);
+ }
+ return a;
+ }
+
+ function _bytes2bi255(a) {
+ var n = _ZERO;
+ for (var i = 0; i < 32; i++) {
+ n.shiftLeft(8);
+ n = n.plus(_bi255(a[i]));
+ }
+ return n;
+ }
+
+ function _pow(n, e) {
+ var result = core.ONE();
+ for (var i = 0; i < 256; i++) {
+ if (core.getbit(e, i) === 1) {
+ result = core.mulmodp(result, n);
+ }
+ n = core.sqrmodp(n);
+ }
+ return result;
+ }
+
+ var _ZERO = _bi255(0);
+ var _ONE = _bi255(1);
+ var _TWO = _bi255(2);
+ // This is the core prime.
+ var _Q = _bi255([0xffff - 18, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,
+ 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,
+ 0xffff, 0xffff, 0x7fff]);
+
+ function _modq(n) {
+ core.reduce(n.n);
+ if (n.cmp(_Q) >= 0) {
+ return _modq(n.minus(_Q));
+ }
+ if (n.cmp(_ZERO) === -1) {
+ return _modq(n.plus(_Q));
+ } else {
+ return n;
+ }
+ }
+
+ // _RECOVERY_EXPONENT = _Q.plus(_bi255(3)).divide(_bi255(8));
+ var _RECOVERY_EXPONENT = _bi255('0ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe');
+ // _D = _Q.minus(_bi255(121665)).divide(_bi255(121666));
+ var _D = _bi255('52036cee2b6ffe738cc740797779e89800700a4d4141d8ab75eb4dca135978a3');
+ // _I = _TWO.pow(_Q.minus(_ONE).divide(_bi255(4)));
+ var _I = _bi255('2b8324804fc1df0b2b4d00993dfbd7a72f431806ad2fe478c4ee1b274a0ea0b0');
+ // _L = _TWO.pow(_bi255(252)).plus(_bi255('14def9dea2f79cd65812631a5cf5d3ed'));
+ var _L = _bi255('1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3ed');
+ var _L_BI = _bi('1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3ed', 16);
+
+
+ // ////////////////////////////////////////////////////////////
+
+ function _isoncurve(p) {
+ var x = p[0];
+ var y = p[1];
+ var xsqr = x.sqr();
+ var ysqr = y.sqr();
+ var v = _D.times(xsqr).times(ysqr);
+ return ysqr.minus(xsqr).minus(_ONE).minus(v).modq().equals(_ZERO);
+ }
+
+ function _xrecover(y) {
+ var ysquared = y.sqr();
+ var xx = ysquared.minus(_ONE).divide(_ONE.plus(_D.times(ysquared)));
+ var x = xx.pow(_RECOVERY_EXPONENT);
+ if (!(x.times(x).minus(xx).equals(_ZERO))) {
+ x = x.times(_I);
+ }
+ if (x.isOdd()) {
+ x = _Q.minus(x);
+ }
+ return x;
+ }
+
+ function _x_pt_add(pt1, pt2) {
+ var x1 = pt1[0];
+ var y1 = pt1[1];
+ var z1 = pt1[2];
+ var t1 = pt1[3];
+ var x2 = pt2[0];
+ var y2 = pt2[1];
+ var z2 = pt2[2];
+ var t2 = pt2[3];
+ var A = y1.minus(x1).times(y2.plus(x2));
+ var B = y1.plus(x1).times(y2.minus(x2));
+ var C = z1.times(_TWO).times(t2);
+ var D = t1.times(_TWO).times(z2);
+ var E = D.plus(C);
+ var F = B.minus(A);
+ var G = B.plus(A);
+ var H = D.minus(C);
+ return [E.times(F), G.times(H), F.times(G), E.times(H)];
+ }
+
+ function _xpt_double(pt1) {
+ var x1 = pt1[0];
+ var y1 = pt1[1];
+ var z1 = pt1[2];
+ var A = x1.times(x1);
+ var B = y1.times(y1);
+ var C = _TWO.times(z1).times(z1);
+ var D = _Q.minus(A);
+ var J = x1.plus(y1);
+ var E = J.times(J).minus(A).minus(B);
+ var G = D.plus(B);
+ var F = G.minus(C);
+ var H = D.minus(B);
+ return [E.times(F), G.times(H), F.times(G), E.times(H)];
+ }
+
+ function _xpt_mult(pt, n) {
+ if (n.equals(_ZERO)) {
+ return [_ZERO, _ONE, _ONE, _ZERO];
+ }
+ var odd = n.isOdd();
+ n.shiftRight(1);
+ var value = _xpt_double(_xpt_mult(pt, n));
+ return odd ? _x_pt_add(value, pt) : value;
+ }
+
+ function _pt_xform(pt) {
+ var x = pt[0];
+ var y = pt[1];
+ return [x, y, _ONE, x.times(y)];
+ }
+
+ function _pt_unxform(pt) {
+ var x = pt[0];
+ var y = pt[1];
+ var z = pt[2];
+ var invz = z.inv();
+ return [x.times(invz), y.times(invz)];
+ }
+
+ function _scalarmult(pt, n) {
+ return _pt_unxform(_xpt_mult(_pt_xform(pt), n));
+ }
+
+ function _bytesgetbit(bytes, n) {
+ return (bytes[bytes.length - (n >>> 3) - 1] >> (n & 7)) & 1;
+ }
+
+ function _xpt_mult_bytes(pt, bytes) {
+ var r = [_ZERO, _ONE, _ONE, _ZERO];
+ for (var i = (bytes.length << 3) - 1; i >= 0; i--) {
+ r = _xpt_double(r);
+ if (_bytesgetbit(bytes, i) === 1) {
+ r = _x_pt_add(r, pt);
+ }
+ }
+ return r;
+ }
+
+ function _scalarmultBytes(pt, bytes) {
+ return _pt_unxform(_xpt_mult_bytes(_pt_xform(pt), bytes));
+ }
+
+ var _by = _bi255(4).divide(_bi255(5));
+ var _bx = _xrecover(_by);
+ var _bp = [_bx, _by];
+
+ function _encodeint(n) {
+ return n.bytes(32).reverse();
+ }
+ function _decodeint(b) {
+ return _bi255(b.slice(0).reverse());
+ }
+
+ function _encodepoint(p) {
+ var v = _encodeint(p[1]);
+ if (p[0].isOdd()) {
+ v[31] |= 0x80;
+ }
+ return v;
+ }
+
+ function _decodepoint(v) {
+ v = v.slice(0);
+ var signbit = v[31] >> 7;
+ v[31] &= 127;
+ var y = _decodeint(v);
+ var x = _xrecover(y);
+ if ((x.n[0] & 1) !== signbit) {
+ x = _Q.minus(x);
+ }
+ var p = [x, y];
+ if (!_isoncurve(p)) {
+ throw ('Point is not on curve');
+ }
+ return p;
+ }
+
+ // //////////////////////////////////////////////////
+
+ /**
+ * Factory function to create a suitable BigInteger.
+ *
+ * @param value
+ * The value for the big integer.
+ * @param base {integer}
+ * Base of the conversion of elements in ``value``.
+ * @returns
+ * A BigInteger object.
+ */
+ function _bi(value, base) {
+ if (base !== undefined) {
+ if (base === 256) {
+ return _bi(utils.string2bytes(value));
+ }
+ return new BigInteger(value, base);
+ } else if (typeof value === 'string') {
+ return new BigInteger(value, 10);
+ } else if ((value instanceof Array) || (value instanceof Uint8Array)
+ || Buffer.isBuffer(value)) {
+ return new BigInteger(value);
+ } else if (typeof value === 'number') {
+ return new BigInteger(value.toString(), 10);
+ } else {
+ throw "Can't convert " + value + " to BigInteger";
+ }
+ }
+
+ function _bi2bytes(n, cnt) {
+ if (cnt === undefined) {
+ cnt = (n.bitLength() + 7) >>> 3;
+ }
+ var bytes = new Array(cnt);
+ for (var i = cnt - 1; i >= 0; i--) {
+ bytes[i] = n[0] & 255; // n.and(0xff);
+ n = n.shiftRight(8);
+ }
+ return bytes;
+ }
+
+ BigInteger.prototype.bytes = function(n) {
+ return _bi2bytes(this, n);
+ };
+
+ // /////////////////////////////////////////////////////////
+
+ function _bytehash(s) {
+ var sha = crypto.createHash('sha512').update(s).digest();
+ return _bi2bytes(_bi(sha), 64).reverse();
+ }
+
+ function _stringhash(s) {
+ var sha = crypto.createHash('sha512').update(s).digest();
+ return _map(_chr, _bi2bytes(_bi(sha), 64)).join('');
+ }
+
+ function _inthash(s) {
+ // Need a leading 0 to prevent sign extension
+ return _bi([0].concat(_bytehash(s)));
+ }
+
+ function _inthash_lo(s) {
+ return _bi255(_bytehash(s).slice(32, 64));
+ }
+
+ function _inthash_mod_l(s) {
+ return _inthash(s).mod(_L_BI);
+ }
+
+ function _get_a(sk) {
+ var a = _inthash_lo(sk);
+ a.n[0] &= 0xfff8;
+ a.n[15] &= 0x3fff;
+ a.n[15] |= 0x4000;
+ return a;
+ }
+
+ function _publickey(sk) {
+ return _encodepoint(_scalarmult(_bp, _get_a(sk)));
+ }
+
+ function _map(f, l) {
+ var result = new Array(l.length);
+ for (var i = 0; i < l.length; i++) {
+ result[i] = f(l[i]);
+ }
+ return result;
+ }
+
+ function _chr(n) {
+ return String.fromCharCode(n);
+ }
+
+ function _ord(c) {
+ return c.charCodeAt(0);
+ }
+
+ function _pt_add(p1, p2) {
+ return _pt_unxform(_x_pt_add(_pt_xform(p1), _pt_xform(p2)));
+ }
+
+
+ // Exports for the API.
+
+ /**
+ * Checks whether a point is on the curve.
+ *
+ * @function
+ * @param point {string}
+ * The point to check for in a byte string representation.
+ * @returns {boolean}
+ * true if the point is on the curve, false otherwise.
+ */
+ ns.isOnCurve = function(point) {
+ try {
+ _isoncurve(_decodepoint(utils.string2bytes(point)));
+ } catch(e) {
+ if (e === 'Point is not on curve') {
+ return false;
+ } else {
+ throw e;
+ }
+ }
+ return true;
+ };
+
+
+ /**
+ * Computes the EdDSA public key.
+ *
+ * <p>Note: Seeds should be a byte string, not a unicode string containing
+ * multi-byte characters.</p>
+ *
+ * @function
+ * @param keySeed {string}
+ * Private key seed in the form of a byte string.
+ * @returns {string}
+ * Public key as byte string computed from the private key seed
+ * (32 bytes).
+ */
+ ns.publicKey = function(keySeed) {
+ return utils.bytes2string(_publickey(keySeed));
+ };
+
+
+ /**
+ * Computes an EdDSA signature of a message.
+ *
+ * <p>Notes:</p>
+ *
+ * <ul>
+ * <li>Unicode messages need to be converted to a byte representation
+ * (e. g. UTF-8).</li>
+ * <li>If `publicKey` is given, and it is *not* a point of the curve,
+ * the signature will be faulty, but no error will be thrown.</li>
+ * </ul>
+ *
+ * @function
+ * @param message {string}
+ * Message in the form of a byte string.
+ * @param keySeed {string}
+ * Private key seed in the form of a byte string.
+ * @param publicKey {string}
+ * Public key as byte string (if not present, it will be computed from
+ * the private key seed).
+ * @returns {string}
+ * Detached message signature in the form of a byte string (64 bytes).
+ */
+ ns.sign = function(message, keySeed, publicKey) {
+ if (publicKey === undefined) {
+ publicKey = _publickey(keySeed);
+ } else {
+ publicKey = utils.string2bytes(publicKey);
+ }
+ var a = _bi(_get_a(keySeed).toString(), 16);
+ var hs = _stringhash(keySeed);
+ var r = _bytehash(hs.slice(32, 64) + message);
+ var rp = _scalarmultBytes(_bp, r);
+ var erp = _encodepoint(rp);
+ r = _bi(r).mod(_bi(1, 10).shiftLeft(512));
+ var s = _map(_chr, erp).join('') + _map(_chr, publicKey).join('') + message;
+ s = _inthash_mod_l(s).multiply(a).add(r).mod(_L_BI);
+ return utils.bytes2string(erp.concat(_encodeint(s)));
+ };
+
+
+ /**
+ * Verifies an EdDSA signature of a message with the public key.
+ *
+ * <p>Note: Unicode messages need to be converted to a byte representation
+ * (e. g. UTF-8).</p>
+ *
+ * @function
+ * @param signature {string}
+ * Message signature in the form of a byte string. Can be detached
+ * (64 bytes), or attached to be sliced off.
+ * @param message {string}
+ * Message in the form of a byte string.
+ * @param publicKey {string}
+ * Public key as byte string (if not present, it will be computed from
+ * the private key seed).
+ * @returns {boolean}
+ * true, if the signature verifies.
+ */
+ ns.verify = function(signature, message, publicKey) {
+ signature = utils.string2bytes(signature.slice(0, 64));
+ publicKey = utils.string2bytes(publicKey);
+ var rpe = signature.slice(0, 32);
+ var rp = _decodepoint(rpe);
+ var a = _decodepoint(publicKey);
+ var s = _decodeint(signature.slice(32, 64));
+ var h = _inthash(utils.bytes2string(rpe.concat(publicKey)) + message);
+ var v1 = _scalarmult(_bp, s);
+ var value = _scalarmultBytes(a, _bi2bytes(h));
+ var v2 = _pt_add(rp, value);
+ return v1[0].equals(v2[0]) && v1[1].equals(v2[1]);
+ };
+
+
+ /**
+ * Generates a new random private key seed of 32 bytes length (256 bit).
+ *
+ * @function
+ * @returns {string}
+ * Byte string containing a new random private key seed.
+ */
+ ns.generateKeySeed = function() {
+ return core.generateKey(false);
+ };
+
+module.exports = ns;
Code Review / simantics / district.git / blobdiff