// Copyright 2017 Joyent, Inc.
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module.exports = {
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DiffieHellman: DiffieHellman,
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generateECDSA: generateECDSA,
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generateED25519: generateED25519
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};
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var assert = require('assert-plus');
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var crypto = require('crypto');
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var Buffer = require('safer-buffer').Buffer;
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var algs = require('./algs');
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var utils = require('./utils');
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var nacl = require('tweetnacl');
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var Key = require('./key');
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var PrivateKey = require('./private-key');
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var CRYPTO_HAVE_ECDH = (crypto.createECDH !== undefined);
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var ecdh = require('ecc-jsbn');
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var ec = require('ecc-jsbn/lib/ec');
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var jsbn = require('jsbn').BigInteger;
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function DiffieHellman(key) {
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utils.assertCompatible(key, Key, [1, 4], 'key');
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this._isPriv = PrivateKey.isPrivateKey(key, [1, 3]);
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this._algo = key.type;
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this._curve = key.curve;
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this._key = key;
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if (key.type === 'dsa') {
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if (!CRYPTO_HAVE_ECDH) {
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throw (new Error('Due to bugs in the node 0.10 ' +
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'crypto API, node 0.12.x or later is required ' +
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'to use DH'));
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}
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this._dh = crypto.createDiffieHellman(
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key.part.p.data, undefined,
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key.part.g.data, undefined);
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this._p = key.part.p;
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this._g = key.part.g;
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if (this._isPriv)
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this._dh.setPrivateKey(key.part.x.data);
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this._dh.setPublicKey(key.part.y.data);
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} else if (key.type === 'ecdsa') {
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if (!CRYPTO_HAVE_ECDH) {
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this._ecParams = new X9ECParameters(this._curve);
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if (this._isPriv) {
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this._priv = new ECPrivate(
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this._ecParams, key.part.d.data);
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}
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return;
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}
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var curve = {
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'nistp256': 'prime256v1',
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'nistp384': 'secp384r1',
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'nistp521': 'secp521r1'
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}[key.curve];
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this._dh = crypto.createECDH(curve);
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if (typeof (this._dh) !== 'object' ||
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typeof (this._dh.setPrivateKey) !== 'function') {
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CRYPTO_HAVE_ECDH = false;
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DiffieHellman.call(this, key);
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return;
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}
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if (this._isPriv)
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this._dh.setPrivateKey(key.part.d.data);
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this._dh.setPublicKey(key.part.Q.data);
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} else if (key.type === 'curve25519') {
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if (this._isPriv) {
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utils.assertCompatible(key, PrivateKey, [1, 5], 'key');
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this._priv = key.part.k.data;
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}
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} else {
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throw (new Error('DH not supported for ' + key.type + ' keys'));
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}
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}
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DiffieHellman.prototype.getPublicKey = function () {
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if (this._isPriv)
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return (this._key.toPublic());
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return (this._key);
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};
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DiffieHellman.prototype.getPrivateKey = function () {
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if (this._isPriv)
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return (this._key);
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else
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return (undefined);
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};
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DiffieHellman.prototype.getKey = DiffieHellman.prototype.getPrivateKey;
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DiffieHellman.prototype._keyCheck = function (pk, isPub) {
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assert.object(pk, 'key');
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if (!isPub)
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utils.assertCompatible(pk, PrivateKey, [1, 3], 'key');
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utils.assertCompatible(pk, Key, [1, 4], 'key');
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if (pk.type !== this._algo) {
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throw (new Error('A ' + pk.type + ' key cannot be used in ' +
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this._algo + ' Diffie-Hellman'));
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}
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if (pk.curve !== this._curve) {
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throw (new Error('A key from the ' + pk.curve + ' curve ' +
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'cannot be used with a ' + this._curve +
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' Diffie-Hellman'));
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}
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if (pk.type === 'dsa') {
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assert.deepEqual(pk.part.p, this._p,
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'DSA key prime does not match');
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assert.deepEqual(pk.part.g, this._g,
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'DSA key generator does not match');
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}
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};
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DiffieHellman.prototype.setKey = function (pk) {
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this._keyCheck(pk);
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if (pk.type === 'dsa') {
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this._dh.setPrivateKey(pk.part.x.data);
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this._dh.setPublicKey(pk.part.y.data);
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} else if (pk.type === 'ecdsa') {
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if (CRYPTO_HAVE_ECDH) {
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this._dh.setPrivateKey(pk.part.d.data);
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this._dh.setPublicKey(pk.part.Q.data);
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} else {
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this._priv = new ECPrivate(
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this._ecParams, pk.part.d.data);
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}
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} else if (pk.type === 'curve25519') {
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var k = pk.part.k;
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if (!pk.part.k)
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k = pk.part.r;
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this._priv = k.data;
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if (this._priv[0] === 0x00)
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this._priv = this._priv.slice(1);
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this._priv = this._priv.slice(0, 32);
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}
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this._key = pk;
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this._isPriv = true;
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};
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DiffieHellman.prototype.setPrivateKey = DiffieHellman.prototype.setKey;
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DiffieHellman.prototype.computeSecret = function (otherpk) {
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this._keyCheck(otherpk, true);
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if (!this._isPriv)
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throw (new Error('DH exchange has not been initialized with ' +
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'a private key yet'));
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var pub;
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if (this._algo === 'dsa') {
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return (this._dh.computeSecret(
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otherpk.part.y.data));
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} else if (this._algo === 'ecdsa') {
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if (CRYPTO_HAVE_ECDH) {
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return (this._dh.computeSecret(
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otherpk.part.Q.data));
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} else {
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pub = new ECPublic(
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this._ecParams, otherpk.part.Q.data);
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return (this._priv.deriveSharedSecret(pub));
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}
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} else if (this._algo === 'curve25519') {
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pub = otherpk.part.A.data;
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while (pub[0] === 0x00 && pub.length > 32)
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pub = pub.slice(1);
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var priv = this._priv;
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assert.strictEqual(pub.length, 32);
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assert.strictEqual(priv.length, 32);
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var secret = nacl.box.before(new Uint8Array(pub),
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new Uint8Array(priv));
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return (Buffer.from(secret));
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}
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throw (new Error('Invalid algorithm: ' + this._algo));
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};
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DiffieHellman.prototype.generateKey = function () {
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var parts = [];
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var priv, pub;
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if (this._algo === 'dsa') {
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this._dh.generateKeys();
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parts.push({name: 'p', data: this._p.data});
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parts.push({name: 'q', data: this._key.part.q.data});
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parts.push({name: 'g', data: this._g.data});
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parts.push({name: 'y', data: this._dh.getPublicKey()});
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parts.push({name: 'x', data: this._dh.getPrivateKey()});
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this._key = new PrivateKey({
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type: 'dsa',
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parts: parts
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});
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this._isPriv = true;
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return (this._key);
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} else if (this._algo === 'ecdsa') {
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if (CRYPTO_HAVE_ECDH) {
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this._dh.generateKeys();
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parts.push({name: 'curve',
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data: Buffer.from(this._curve)});
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parts.push({name: 'Q', data: this._dh.getPublicKey()});
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parts.push({name: 'd', data: this._dh.getPrivateKey()});
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this._key = new PrivateKey({
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type: 'ecdsa',
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curve: this._curve,
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parts: parts
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});
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this._isPriv = true;
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return (this._key);
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} else {
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var n = this._ecParams.getN();
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var r = new jsbn(crypto.randomBytes(n.bitLength()));
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var n1 = n.subtract(jsbn.ONE);
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priv = r.mod(n1).add(jsbn.ONE);
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pub = this._ecParams.getG().multiply(priv);
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priv = Buffer.from(priv.toByteArray());
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pub = Buffer.from(this._ecParams.getCurve().
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encodePointHex(pub), 'hex');
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this._priv = new ECPrivate(this._ecParams, priv);
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parts.push({name: 'curve',
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data: Buffer.from(this._curve)});
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parts.push({name: 'Q', data: pub});
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parts.push({name: 'd', data: priv});
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this._key = new PrivateKey({
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type: 'ecdsa',
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curve: this._curve,
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parts: parts
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});
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this._isPriv = true;
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return (this._key);
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}
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} else if (this._algo === 'curve25519') {
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var pair = nacl.box.keyPair();
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priv = Buffer.from(pair.secretKey);
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pub = Buffer.from(pair.publicKey);
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priv = Buffer.concat([priv, pub]);
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assert.strictEqual(priv.length, 64);
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assert.strictEqual(pub.length, 32);
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parts.push({name: 'A', data: pub});
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parts.push({name: 'k', data: priv});
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this._key = new PrivateKey({
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type: 'curve25519',
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parts: parts
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});
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this._isPriv = true;
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return (this._key);
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}
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throw (new Error('Invalid algorithm: ' + this._algo));
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};
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DiffieHellman.prototype.generateKeys = DiffieHellman.prototype.generateKey;
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/* These are helpers for using ecc-jsbn (for node 0.10 compatibility). */
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function X9ECParameters(name) {
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var params = algs.curves[name];
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assert.object(params);
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var p = new jsbn(params.p);
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var a = new jsbn(params.a);
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var b = new jsbn(params.b);
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var n = new jsbn(params.n);
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var h = jsbn.ONE;
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var curve = new ec.ECCurveFp(p, a, b);
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var G = curve.decodePointHex(params.G.toString('hex'));
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this.curve = curve;
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this.g = G;
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this.n = n;
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this.h = h;
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}
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X9ECParameters.prototype.getCurve = function () { return (this.curve); };
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X9ECParameters.prototype.getG = function () { return (this.g); };
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X9ECParameters.prototype.getN = function () { return (this.n); };
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X9ECParameters.prototype.getH = function () { return (this.h); };
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function ECPublic(params, buffer) {
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this._params = params;
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if (buffer[0] === 0x00)
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buffer = buffer.slice(1);
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this._pub = params.getCurve().decodePointHex(buffer.toString('hex'));
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}
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function ECPrivate(params, buffer) {
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this._params = params;
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this._priv = new jsbn(utils.mpNormalize(buffer));
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}
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ECPrivate.prototype.deriveSharedSecret = function (pubKey) {
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assert.ok(pubKey instanceof ECPublic);
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var S = pubKey._pub.multiply(this._priv);
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return (Buffer.from(S.getX().toBigInteger().toByteArray()));
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};
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function generateED25519() {
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var pair = nacl.sign.keyPair();
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var priv = Buffer.from(pair.secretKey);
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var pub = Buffer.from(pair.publicKey);
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assert.strictEqual(priv.length, 64);
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assert.strictEqual(pub.length, 32);
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var parts = [];
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parts.push({name: 'A', data: pub});
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parts.push({name: 'k', data: priv.slice(0, 32)});
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var key = new PrivateKey({
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type: 'ed25519',
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parts: parts
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});
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return (key);
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}
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/* Generates a new ECDSA private key on a given curve. */
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function generateECDSA(curve) {
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var parts = [];
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var key;
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if (CRYPTO_HAVE_ECDH) {
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/*
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* Node crypto doesn't expose key generation directly, but the
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* ECDH instances can generate keys. It turns out this just
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* calls into the OpenSSL generic key generator, and we can
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* read its output happily without doing an actual DH. So we
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* use that here.
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*/
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var osCurve = {
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'nistp256': 'prime256v1',
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'nistp384': 'secp384r1',
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'nistp521': 'secp521r1'
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}[curve];
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var dh = crypto.createECDH(osCurve);
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dh.generateKeys();
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parts.push({name: 'curve',
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data: Buffer.from(curve)});
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parts.push({name: 'Q', data: dh.getPublicKey()});
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parts.push({name: 'd', data: dh.getPrivateKey()});
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key = new PrivateKey({
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type: 'ecdsa',
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curve: curve,
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parts: parts
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});
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return (key);
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} else {
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var ecParams = new X9ECParameters(curve);
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/* This algorithm taken from FIPS PUB 186-4 (section B.4.1) */
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var n = ecParams.getN();
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/*
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* The crypto.randomBytes() function can only give us whole
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* bytes, so taking a nod from X9.62, we round up.
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*/
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var cByteLen = Math.ceil((n.bitLength() + 64) / 8);
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var c = new jsbn(crypto.randomBytes(cByteLen));
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var n1 = n.subtract(jsbn.ONE);
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var priv = c.mod(n1).add(jsbn.ONE);
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var pub = ecParams.getG().multiply(priv);
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priv = Buffer.from(priv.toByteArray());
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pub = Buffer.from(ecParams.getCurve().
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encodePointHex(pub), 'hex');
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parts.push({name: 'curve', data: Buffer.from(curve)});
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parts.push({name: 'Q', data: pub});
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parts.push({name: 'd', data: priv});
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key = new PrivateKey({
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type: 'ecdsa',
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curve: curve,
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parts: parts
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});
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return (key);
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}
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}
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