--- /dev/null
+// Copyright 2015 Joyent, Inc.
+
+module.exports = DiffieHellman;
+
+var assert = require('assert-plus');
+var crypto = require('crypto');
+var algs = require('./algs');
+var utils = require('./utils');
+var ed;
+
+var Key = require('./key');
+var PrivateKey = require('./private-key');
+
+var CRYPTO_HAVE_ECDH = (crypto.createECDH !== undefined);
+
+var ecdh, ec, jsbn;
+
+function DiffieHellman(key) {
+ utils.assertCompatible(key, Key, [1, 4], 'key');
+ this._isPriv = PrivateKey.isPrivateKey(key, [1, 3]);
+ this._algo = key.type;
+ this._curve = key.curve;
+ this._key = key;
+ if (key.type === 'dsa') {
+ if (!CRYPTO_HAVE_ECDH) {
+ throw (new Error('Due to bugs in the node 0.10 ' +
+ 'crypto API, node 0.12.x or later is required ' +
+ 'to use DH'));
+ }
+ this._dh = crypto.createDiffieHellman(
+ key.part.p.data, undefined,
+ key.part.g.data, undefined);
+ this._p = key.part.p;
+ this._g = key.part.g;
+ if (this._isPriv)
+ this._dh.setPrivateKey(key.part.x.data);
+ this._dh.setPublicKey(key.part.y.data);
+
+ } else if (key.type === 'ecdsa') {
+ if (!CRYPTO_HAVE_ECDH) {
+ if (ecdh === undefined)
+ ecdh = require('ecc-jsbn');
+ if (ec === undefined)
+ ec = require('ecc-jsbn/lib/ec');
+ if (jsbn === undefined)
+ jsbn = require('jsbn').BigInteger;
+
+ this._ecParams = new X9ECParameters(this._curve);
+
+ if (this._isPriv) {
+ this._priv = new ECPrivate(
+ this._ecParams, key.part.d.data);
+ }
+ return;
+ }
+
+ var curve = {
+ 'nistp256': 'prime256v1',
+ 'nistp384': 'secp384r1',
+ 'nistp521': 'secp521r1'
+ }[key.curve];
+ this._dh = crypto.createECDH(curve);
+ if (typeof (this._dh) !== 'object' ||
+ typeof (this._dh.setPrivateKey) !== 'function') {
+ CRYPTO_HAVE_ECDH = false;
+ DiffieHellman.call(this, key);
+ return;
+ }
+ if (this._isPriv)
+ this._dh.setPrivateKey(key.part.d.data);
+ this._dh.setPublicKey(key.part.Q.data);
+
+ } else if (key.type === 'curve25519') {
+ if (ed === undefined)
+ ed = require('jodid25519');
+
+ if (this._isPriv) {
+ this._priv = key.part.r.data;
+ if (this._priv[0] === 0x00)
+ this._priv = this._priv.slice(1);
+ this._priv = this._priv.slice(0, 32);
+ }
+
+ } else {
+ throw (new Error('DH not supported for ' + key.type + ' keys'));
+ }
+}
+
+DiffieHellman.prototype.getPublicKey = function () {
+ if (this._isPriv)
+ return (this._key.toPublic());
+ return (this._key);
+};
+
+DiffieHellman.prototype.getPrivateKey = function () {
+ if (this._isPriv)
+ return (this._key);
+ else
+ return (undefined);
+};
+DiffieHellman.prototype.getKey = DiffieHellman.prototype.getPrivateKey;
+
+DiffieHellman.prototype._keyCheck = function (pk, isPub) {
+ assert.object(pk, 'key');
+ if (!isPub)
+ utils.assertCompatible(pk, PrivateKey, [1, 3], 'key');
+ utils.assertCompatible(pk, Key, [1, 4], 'key');
+
+ if (pk.type !== this._algo) {
+ throw (new Error('A ' + pk.type + ' key cannot be used in ' +
+ this._algo + ' Diffie-Hellman'));
+ }
+
+ if (pk.curve !== this._curve) {
+ throw (new Error('A key from the ' + pk.curve + ' curve ' +
+ 'cannot be used with a ' + this._curve +
+ ' Diffie-Hellman'));
+ }
+
+ if (pk.type === 'dsa') {
+ assert.deepEqual(pk.part.p, this._p,
+ 'DSA key prime does not match');
+ assert.deepEqual(pk.part.g, this._g,
+ 'DSA key generator does not match');
+ }
+};
+
+DiffieHellman.prototype.setKey = function (pk) {
+ this._keyCheck(pk);
+
+ if (pk.type === 'dsa') {
+ this._dh.setPrivateKey(pk.part.x.data);
+ this._dh.setPublicKey(pk.part.y.data);
+
+ } else if (pk.type === 'ecdsa') {
+ if (CRYPTO_HAVE_ECDH) {
+ this._dh.setPrivateKey(pk.part.d.data);
+ this._dh.setPublicKey(pk.part.Q.data);
+ } else {
+ this._priv = new ECPrivate(
+ this._ecParams, pk.part.d.data);
+ }
+
+ } else if (pk.type === 'curve25519') {
+ this._priv = pk.part.r.data;
+ if (this._priv[0] === 0x00)
+ this._priv = this._priv.slice(1);
+ this._priv = this._priv.slice(0, 32);
+ }
+ this._key = pk;
+ this._isPriv = true;
+};
+DiffieHellman.prototype.setPrivateKey = DiffieHellman.prototype.setKey;
+
+DiffieHellman.prototype.computeSecret = function (otherpk) {
+ this._keyCheck(otherpk, true);
+ if (!this._isPriv)
+ throw (new Error('DH exchange has not been initialized with ' +
+ 'a private key yet'));
+
+ var pub;
+ if (this._algo === 'dsa') {
+ return (this._dh.computeSecret(
+ otherpk.part.y.data));
+
+ } else if (this._algo === 'ecdsa') {
+ if (CRYPTO_HAVE_ECDH) {
+ return (this._dh.computeSecret(
+ otherpk.part.Q.data));
+ } else {
+ pub = new ECPublic(
+ this._ecParams, otherpk.part.Q.data);
+ return (this._priv.deriveSharedSecret(pub));
+ }
+
+ } else if (this._algo === 'curve25519') {
+ pub = otherpk.part.R.data;
+ if (pub[0] === 0x00)
+ pub = pub.slice(1);
+
+ var secret = ed.dh.computeKey(
+ this._priv.toString('binary'),
+ pub.toString('binary'));
+
+ return (new Buffer(secret, 'binary'));
+ }
+
+ throw (new Error('Invalid algorithm: ' + this._algo));
+};
+
+DiffieHellman.prototype.generateKey = function () {
+ var parts = [];
+ var priv, pub;
+ if (this._algo === 'dsa') {
+ this._dh.generateKeys();
+
+ parts.push({name: 'p', data: this._p.data});
+ parts.push({name: 'q', data: this._key.part.q.data});
+ parts.push({name: 'g', data: this._g.data});
+ parts.push({name: 'y', data: this._dh.getPublicKey()});
+ parts.push({name: 'x', data: this._dh.getPrivateKey()});
+ this._key = new PrivateKey({
+ type: 'dsa',
+ parts: parts
+ });
+ this._isPriv = true;
+ return (this._key);
+
+ } else if (this._algo === 'ecdsa') {
+ if (CRYPTO_HAVE_ECDH) {
+ this._dh.generateKeys();
+
+ parts.push({name: 'curve',
+ data: new Buffer(this._curve)});
+ parts.push({name: 'Q', data: this._dh.getPublicKey()});
+ parts.push({name: 'd', data: this._dh.getPrivateKey()});
+ this._key = new PrivateKey({
+ type: 'ecdsa',
+ curve: this._curve,
+ parts: parts
+ });
+ this._isPriv = true;
+ return (this._key);
+
+ } else {
+ var n = this._ecParams.getN();
+ var r = new jsbn(crypto.randomBytes(n.bitLength()));
+ var n1 = n.subtract(jsbn.ONE);
+ priv = r.mod(n1).add(jsbn.ONE);
+ pub = this._ecParams.getG().multiply(priv);
+
+ priv = new Buffer(priv.toByteArray());
+ pub = new Buffer(this._ecParams.getCurve().
+ encodePointHex(pub), 'hex');
+
+ this._priv = new ECPrivate(this._ecParams, priv);
+
+ parts.push({name: 'curve',
+ data: new Buffer(this._curve)});
+ parts.push({name: 'Q', data: pub});
+ parts.push({name: 'd', data: priv});
+
+ this._key = new PrivateKey({
+ type: 'ecdsa',
+ curve: this._curve,
+ parts: parts
+ });
+ this._isPriv = true;
+ return (this._key);
+ }
+
+ } else if (this._algo === 'curve25519') {
+ priv = ed.dh.generateKey();
+ pub = ed.dh.publicKey(priv);
+ this._priv = priv = new Buffer(priv, 'binary');
+ pub = new Buffer(pub, 'binary');
+
+ parts.push({name: 'R', data: pub});
+ parts.push({name: 'r', data: Buffer.concat([priv, pub])});
+ this._key = new PrivateKey({
+ type: 'curve25519',
+ parts: parts
+ });
+ this._isPriv = true;
+ return (this._key);
+ }
+
+ throw (new Error('Invalid algorithm: ' + this._algo));
+};
+DiffieHellman.prototype.generateKeys = DiffieHellman.prototype.generateKey;
+
+/* These are helpers for using ecc-jsbn (for node 0.10 compatibility). */
+
+function X9ECParameters(name) {
+ var params = algs.curves[name];
+ assert.object(params);
+
+ var p = new jsbn(params.p);
+ var a = new jsbn(params.a);
+ var b = new jsbn(params.b);
+ var n = new jsbn(params.n);
+ var h = jsbn.ONE;
+ var curve = new ec.ECCurveFp(p, a, b);
+ var G = curve.decodePointHex(params.G.toString('hex'));
+
+ this.curve = curve;
+ this.g = G;
+ this.n = n;
+ this.h = h;
+}
+X9ECParameters.prototype.getCurve = function () { return (this.curve); };
+X9ECParameters.prototype.getG = function () { return (this.g); };
+X9ECParameters.prototype.getN = function () { return (this.n); };
+X9ECParameters.prototype.getH = function () { return (this.h); };
+
+function ECPublic(params, buffer) {
+ this._params = params;
+ if (buffer[0] === 0x00)
+ buffer = buffer.slice(1);
+ this._pub = params.getCurve().decodePointHex(buffer.toString('hex'));
+}
+
+function ECPrivate(params, buffer) {
+ this._params = params;
+ this._priv = new jsbn(utils.mpNormalize(buffer));
+}
+ECPrivate.prototype.deriveSharedSecret = function (pubKey) {
+ assert.ok(pubKey instanceof ECPublic);
+ var S = pubKey._pub.multiply(this._priv);
+ return (new Buffer(S.getX().toBigInteger().toByteArray()));
+};