75 lines
2.3 KiB
JavaScript
75 lines
2.3 KiB
JavaScript
'use strict';
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var aes = require('aes-js');
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var randomBytes = require('./random-bytes.js');
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var utils = require('./utils.js');
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function Randomish() {
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if (!(this instanceof Randomish)) { throw new Error('missing new'); }
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var weak = (randomBytes._weakCrypto || false);
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var entropyBits = (weak ? 0: ((32 + 16) * 8));
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Object.defineProperty(this, 'entropy', {
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enumerable: true,
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get: function() { return entropyBits; }
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});
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var entropy = new aes.ModeOfOperation.cbc(
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Randomish.randomishBytes(32),
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Randomish.randomishBytes(16)
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);
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utils.defineProperty(this, 'feedEntropy', function(data, expectedEntropyBits) {
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if (!data) { data = ''; }
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if (!expectedEntropyBits) { expectedEntropyBits = 0; }
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if (parseInt(expectedEntropyBits) != expectedEntropyBits) {
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throw new Error('invalid expectedEntropyBits');
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}
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data = (new Date()).getTime() + '-' + JSON.stringify(data) + '-' + data.toString();
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var hashed = utils.sha3(new Buffer(data, 'utf8'));
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entropyBits += expectedEntropyBits + (weak ? 0: ((32) * 8));
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// Feed the hashed data and random data to the mode of operation
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entropy.encrypt(hashed.slice(0, 16));
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entropy.encrypt(randomBytes(16));
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entropy.encrypt(hashed.slice(0, 16));
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return new Buffer(entropy.encrypt(randomBytes(16)));
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});
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utils.defineProperty(this, 'randomBytes', function(length, key) {
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if (parseInt(length) != length || length <= 0 || length > 1024) {
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throw new Error('invalid length');
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}
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// If we don't have a key, create one
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if (!key) {
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key = Buffer.concat([this.feedEntropy(), this.feedEntropy()]);
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}
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if (!Buffer.isBuffer(key) || key.length !== 32) {
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throw new Error('invalid key');
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}
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var aesCbc = new aes.ModeOfOperation.cbc(key, this.feedEntropy());
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var result = new Buffer(0);
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while (result.length < length) {
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result = Buffer.concat([result, this.feedEntropy()]);
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}
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return result.slice(0, length);
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});
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this.feedEntropy();
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}
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utils.defineProperty(Randomish, 'randomishBytes', function(length) {
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return randomBytes(length);
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});
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module.exports = Randomish
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