random.php File Reference

Variables
if(!defined('PHP_VERSION_ID')) if(PHP_VERSION_ID >=70000) if(!defined('RANDOM_COMPAT_READ_BUFFER'))	$RandomCompatDIR = dirname(__FILE__)

Variable Documentation

$RandomCompatDIR

if(!is_callable('random_bytes')) if (!is_callable( 'random_int')) $RandomCompatDIR = dirname(__FILE__)

Random_* Compatibility Library for using the new PHP 7 random_* API in PHP 5 projects

Version

2.0.17 @released 2018-07-04

The MIT License (MIT)

Copyright (c) 2015 - 2018 Paragon Initiative Enterprises

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. PHP 7.0.0 and newer have these functions natively.

PHP 5.2.0 - 5.6.x way to implement random_bytes()

We use conditional statements here to define the function in accordance to the operating environment. It's a micro-optimization.

In order of preference:

1. Use libsodium if available.
2. fread() /dev/urandom if available (never on Windows)
3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)
4. COM('CAPICOM.Utilities.1')->GetRandom()

See RATIONALE.md for our reasoning behind this particular order

Reading directly from /dev/urandom:

mcrypt_create_iv()

We only want to use mcypt_create_iv() if:

• random_bytes() hasn't already been defined
• the mcrypt extensions is loaded
• One of these two conditions is true:
  • We're on Windows (DIRECTORY_SEPARATOR !== '/')
  • We're not on Windows and /dev/urandom is readabale (i.e. we're not in a chroot jail)
• Special case:
  • If we're not on Windows, but the PHP version is between 5.6.10 and 5.6.12, we don't want to use mcrypt. It will hang indefinitely. This is bad.
  • If we're on Windows, we want to use PHP >= 5.3.7 or else we get insufficient entropy errors.

This is a Windows-specific fallback, for when the mcrypt extension isn't loaded.

@psalm-suppress TypeDoesNotContainType

throw new Exception

We don't have any more options, so let's throw an exception right now and hope the developer won't let it fail silently.

Parameters

mixed

$length

@psalm-suppress InvalidReturnType

Exceptions

Exception

Returns

string