89 lines
1.7 KiB
JavaScript
89 lines
1.7 KiB
JavaScript
'use strict';
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// Load modules
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const Crypto = require('crypto');
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const Boom = require('boom');
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// Declare internals
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const internals = {};
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// Generate a cryptographically strong pseudo-random data
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exports.randomString = function (size) {
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const buffer = exports.randomBits((size + 1) * 6);
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if (buffer instanceof Error) {
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return buffer;
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}
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const string = buffer.toString('base64').replace(/\+/g, '-').replace(/\//g, '_').replace(/\=/g, '');
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return string.slice(0, size);
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};
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// Return a random string of digits
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exports.randomDigits = function (size) {
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const buffer = exports.randomBits(size * 8);
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if (buffer instanceof Error) {
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return buffer;
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}
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const digits = [];
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for (let i = 0; i < buffer.length; ++i) {
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digits.push(Math.floor(buffer[i] / 25.6));
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}
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return digits.join('');
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};
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// Generate a buffer of random bits
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exports.randomBits = function (bits) {
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if (!bits ||
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bits < 0) {
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return Boom.internal('Invalid random bits count');
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}
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const bytes = Math.ceil(bits / 8);
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try {
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return Crypto.randomBytes(bytes);
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}
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catch (err) {
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return Boom.internal('Failed generating random bits: ' + err.message);
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}
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};
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// Compare two strings using fixed time algorithm (to prevent time-based analysis of MAC digest match)
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exports.fixedTimeComparison = function (a, b) {
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if (typeof a !== 'string' ||
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typeof b !== 'string') {
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return false;
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}
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let mismatch = (a.length === b.length ? 0 : 1);
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if (mismatch) {
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b = a;
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}
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for (let i = 0; i < a.length; ++i) {
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const ac = a.charCodeAt(i);
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const bc = b.charCodeAt(i);
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mismatch |= (ac ^ bc);
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}
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return (mismatch === 0);
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};
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