64 lines
1.4 KiB
JavaScript
64 lines
1.4 KiB
JavaScript
/*!
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* random-browser.js - randomness for bcoin
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* Copyright (c) 2014-2017, Christopher Jeffrey (MIT License).
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* https://github.com/bcoin-org/bcoin
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*/
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'use strict';
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/**
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* @module crypto.random-browser
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* @ignore
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*/
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const crypto = global.crypto || global.msCrypto || {};
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/**
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* Generate pseudo-random bytes.
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* @param {Number} size
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* @returns {Buffer}
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*/
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exports.randomBytes = function randomBytes(size) {
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let data = new Uint8Array(size);
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crypto.getRandomValues(data);
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return Buffer.from(data.buffer);
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};
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if (!crypto.getRandomValues) {
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// Out of luck here. Use bad randomness for now.
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exports.randomBytes = function randomBytes(size) {
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let data = Buffer.allocUnsafe(size);
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for (let 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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/**
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* Generate a random uint32.
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* Probably more cryptographically sound than
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* `Math.random()`.
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* @returns {Number}
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*/
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exports.randomInt = function randomInt() {
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return exports.randomBytes(4).readUInt32LE(0, true);
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};
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/**
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* Generate a random number within a range.
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* Probably more cryptographically sound than
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* `Math.random()`.
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* @param {Number} min - Inclusive.
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* @param {Number} max - Exclusive.
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* @returns {Number}
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*/
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exports.randomRange = function randomRange(min, max) {
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let num = exports.randomInt();
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return Math.floor((num / 0x100000000) * (max - min) + min);
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};
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