PHP Random Bytes: Generate cryptographically strong random bytes

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Last Updated		Ratings				Unique User Downloads		Download Rankings
2025-05-08 (1 month ago)		Not enough user ratings				Total: 175		All time: 8,780 This week: 571

Version		License		PHP version		Categories
`random-bytes` 0.16		GNU General Publi...		5.4		PHP 5, Cryptography, Security

Description

Author

Martin Latter

This class can generate cryptographically strong random bytes.

It can generate a string of bytes with random values using a given method.

Currently it can use either methods using mcrypt, OpenSSL, or /dev/urandom on Linux. The default is to use mcrypt.

Innovation Award

May 2015
Number 5

Prize: One downloadable e-book of choice by O'Reilly

Many cryptography algorithms use random numbers to make it harder to break the security measures based on those algorithms.

There are many pseudo-random number generators that can be used to generate cryptographically strong data values.

This class can generate random streams of bytes that are more secure to use in cryptography applications by either using /dev/random on Linux, OpenSSL or mcrypt libraries.

Manuel Lemos

Martin Latter

Performance

Level

Name:	Martin Latter `<contact>`
Classes:	8 packages by Martin Latter
Country:	United Kingdom
Age:	???
All time rank:	1296	60 in United Kingdom
Week rank:	195	9 in United Kingdom

Level 4

Innovation award

Nominee: 5x

Example


<?php



/**

    * Example web server usage of RandomBytes class.

    * Martin Latter, 13/04/2015

*/



##################################################

declare(strict_types=1);

mb_internal_encoding('UTF-8');

mb_http_output('UTF-8');

header('Content-Type: text/html; charset=utf-8');

##################################################



##################################################

require('classes/randombytes.class.php');

use Tinram\RandomBytes\RandomBytes;

##################################################





$aRandGenMethods = ['openssl', 'urandom', 'random_bytes'];



$bSubmitted = (isset($_POST['submit_check'])) ? true : false;





function generateTable(array $aData): void

{

    echo '

        <table>

            <tr><td class="tfirst">raw</td><td>' . $aData['raw'] . '</td></tr>

            <tr><td>raw, hex</td><td>' . $aData['hex']. '</td></tr>

            <tr><td>SHA256</td><td>' . $aData['sha'] . '</td></tr>

            <tr><td>SHA256 <small>(bytes)</small></td><td>' . $aData['shabytes'] . '</td></tr>

            <tr><td>Whirlpool</td><td>' . $aData['whirlpool'] . '</td></tr>

        </table>

    ';

}



?><!DOCTYPE html>



<html lang="en">



    <head>



        <meta charset="utf-8">



        <title>Random Bytes</title>



        <meta name="author" content="Martin Latter">



        <style>



            html * {margin:0; padding:0;}

            body {font:0.83em verdana,arial,helvetica,sans-serif; background:#fff; color:#000; margin:4em 0 0 4em;}



            h1 {margin:0 0 20px 0; font-size:1.1em;}



            div#frbcont {width:376px; margin:0 0 60px 0;}

            form#frb label {margin:0 5px 0 0;}

            form#frb input, form#frb select {border-radius:5px; background:#f2f9f9; padding:2px; border:1px solid #c8e4ff; background:linear-gradient(to top, #ebf8ff, #ffffff 80%);}

            form#frb select {margin:0 12px 0 0;}

            form#frb select#chars {width:50px;}

            form#frb select#genmethod {width:120px;}

            form#frb input[type='submit'] {width:80px; height:24px; color:#333; background:#f7ffff; border:0; font-weight:bold; text-align:center; margin-top:10px; padding-bottom:3px; height:25px; background:linear-gradient(to bottom, #f7ffff, #c8e4ff 100%);}

            form#frb input[type='submit']:hover {background:#39f; color:#fff; cursor:pointer;}



            table {border-collapse:collapse;}

            td {padding:4px; border:1px solid #bbb;}

            td.tfirst {width:130px;}



        </style>



    </head>



    <body>



        <h1>Random Bytes</h1>



        <div id="frbcont">



            <form id="frb" method="post" action="<?php echo htmlspecialchars(strip_tags($_SERVER['PHP_SELF']), ENT_QUOTES, 'UTF-8'); ?>">



                <div>



                    <label for="chars" title="number of characters">chars</label>

                    <select id="chars" name="chars">

                    <?php



                        $iChars = ($bSubmitted) ? (int) $_POST['chars'] : 0;

                        $sSelected = '';

                        $sOut = '';



                        for ($i = 16; $i < 72; $i += 8)

                        {

                            $sSelected = ($i !== $iChars) ? '' : ' selected';

                            $sOut .= '<option value="' . $i . '"' . $sSelected . '>' . $i . '</option>';

                        }



                        echo $sOut;

                    ?>



                    </select>



                    <label for="genmethod" title="random bytes generation method">method</label>

                    <select id="genmethod" name="genmethod">

                    <?php



                        $sOut = '';



                        foreach ($aRandGenMethods as $sMethod)

                        {

                            $sSelected = ($bSubmitted && $_POST['genmethod'] === $sMethod) ? ' selected' : '';

                            $sOut .= '<option value="' . $sMethod . '"' . $sSelected . '>' . $sMethod . '</option>';

                        }



                        echo $sOut;

                    ?>



                    </select>



                    <input type="submit" value="generate">



                </div>



                <input type="hidden" name="submit_check">



            </form>



        </div>



        <?php



            if ($bSubmitted)

            {

                $iChars = (int) $_POST['chars'];

                $aData = RandomBytes::generate($iChars, htmlentities(strip_tags($_POST['genmethod'])));

                generateTable($aData);

            }



        ?>



    </body>



</html>

Details

Random Bytes

Generate cryptographically-strong random bytes.

Purpose

Create random bytes – as cryptographically-strong as possible – from available sources of entropy, and display in different output formats.

Crypto Sources

Linux/Unix: OpenSSL, `random_bytes()`, /dev/urandom
Windows: OpenSSL, `random_bytes()`

Random Bytes Definitions:

openssl
random_bytes
urandom

Usage

Prototype

    array RandomBytes::generate(int $length, string $source);

Example

    require('randombytes.class.php');
    use Tinram\RandomBytes\RandomBytes;
    $aData = RandomBytes::generate(32, 'openssl');
    var_dump($aData);

Details

The random bytes generated are only as good as the underlying entropy generator of the OS.

Linux's /dev/urandom entropy source is a non-blocking generator 'suitable for most cryptographic purposes'. (/dev/random, being blocking, isn't suitable for this script.)

OpenBSD and FreeBSD have non-blocking /dev/random implementations.

The random_bytes() function was added to PHP version 7.0

License

Random Bytes is released under the GPL v.3.

Files (5)

File	Role	Description
`classes` (1 file)
`LICENSE`	Lic.	License text
`randombytes_example.php`	Example	Example script
`randombytes_example2.php`	Aux.	Auxiliary script
`README.md`	Data	Documentation

Files (5)

classes

File	Role	Description
`randombytes.class.php`	Class	Class source

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