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'use strict';
// Load modules
const Crypto = require('crypto');
const Boom = require('boom');
// Declare internals
const internals = {};
// Generate a cryptographically strong pseudo-random data
exports.randomString = function (size) {
const buffer = exports.randomBits((size + 1) * 6);
const string = buffer.toString('base64').replace(/\+/g, '-').replace(/\//g, '_').replace(/\=/g, '');
return string.slice(0, size);
};
// Return a random string of digits
exports.randomDigits = function (size) {
const digits = [];
let buffer = internals.random(size * 2); // Provision twice the amount of bytes needed to increase chance of single pass
let pos = 0;
while (digits.length < size) {
if (pos >= buffer.length) {
buffer = internals.random(size * 2);
pos = 0;
}
if (buffer[pos] < 250) {
digits.push(buffer[pos] % 10);
}
++pos;
}
return digits.join('');
};
// Generate a buffer of random bits
exports.randomBits = function (bits) {
if (!bits ||
bits < 0) {
throw Boom.internal('Invalid random bits count');
}
const bytes = Math.ceil(bits / 8);
return internals.random(bytes);
};
exports.fixedTimeComparison = function (a, b) {
try {
return Crypto.timingSafeEqual(Buffer.from(a), Buffer.from(b));
}
catch (err) {
return false;
}
};
internals.random = function (bytes) {
try {
return Crypto.randomBytes(bytes);
}
catch (err) {
throw Boom.internal('Failed generating random bits: ' + err.message);
}
};