117 lines
2.5 KiB
JavaScript
117 lines
2.5 KiB
JavaScript
/*!
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* backend-browser.js - browser crypto backend for bcoin
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* Copyright (c) 2014-2016, Christopher Jeffrey (MIT License).
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* https://github.com/bcoin-org/bcoin
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*/
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/* jshint worker: true */
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'use strict';
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var assert = require('assert');
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var hashjs = require('hash.js');
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var aes = require('./aes');
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var backend = exports;
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var global, crypto, subtle;
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global = (function() {
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if (typeof window !== 'undefined')
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return window;
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if (typeof self !== 'undefined')
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return self;
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throw new Error('No global found.');
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})();
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crypto = global.crypto || global.msCrypto;
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subtle = crypto ? crypto.subtle : null;
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backend.hash = function hash(alg, data) {
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return new Buffer(hashjs[alg]().update(data).digest());
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};
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backend.hmac = function hmac(alg, data, salt) {
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var hash = hashjs[alg];
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var hmac;
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assert(hash != null, 'Unknown algorithm.');
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hmac = hashjs.hmac(hash, salt);
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return new Buffer(hmac.update(data).digest());
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};
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backend.pbkdf2 = null;
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backend.pbkdf2Async = function pbkdf2Async(key, salt, iter, len, alg) {
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var algo = { name: 'PBKDF2' };
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var use = ['deriveBits'];
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var length = len * 8;
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var options, promise;
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options = {
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name: 'PBKDF2',
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salt: salt,
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iterations: iter,
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hash: getHash(alg)
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};
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promise = subtle.importKey('raw', key, algo, false, use);
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return promise.then(function(key) {
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return subtle.deriveBits(options, key, length);
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}).then(function(result) {
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return new Buffer(result);
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});
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};
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if (!subtle || !subtle.importKey || !subtle.deriveBits)
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backend.pbkdf2Async = null;
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backend.encipher = function encipher(data, key, iv) {
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return aes.cbc.encrypt(data, key, iv);
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};
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backend.decipher = function decipher(data, key, iv) {
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try {
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return aes.cbc.decrypt(data, key, iv);
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} catch (e) {
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throw new Error('Bad key for decryption.');
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}
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};
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backend.randomBytes = function randomBytes(n) {
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var data = new Uint8Array(n);
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crypto.getRandomValues(data);
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return new Buffer(data.buffer);
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};
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if (!crypto || !crypto.getRandomValues) {
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// Out of luck here. Use bad randomness for now.
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backend.randomBytes = function randomBytes(n) {
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var data = new Buffer(n);
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var i;
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for (i = 0; i < data.length; i++)
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data[i] = Math.floor(Math.random() * 256);
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return data;
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};
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}
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function getHash(name) {
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switch (name) {
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case 'sha1':
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return 'SHA-1';
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case 'sha256':
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return 'SHA-256';
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case 'sha384':
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return 'SHA-384';
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case 'sha512':
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return 'SHA-512';
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default:
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throw new Error('Unknown hash.');
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}
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}
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