PHP

Generating Repeatable Random Data for Testing/Debugging

See more PRNG Examples

Demonstrates how to use the Fortuna PRNG to generate random-looking but repeatable non-random data for the purpose of testing and debugging. Chilkat2 PHP

<?php

use Chilkat2\Prng;

$success = false;

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

$success = false;

$fortuna = new Prng();

// Normally an application would seed the PRNG with entropy from
// some real random source.  However, sometimes we want the same
// random sequence of bytes for testing and debugging purposes.
// This a reason why GetEntropy and AddEntropy are two different methods.
// An application could omit the call to GetEntropy, and instead pass
// non-random data to AddEntropy. For example:

// Seed the PRNG with non-entropy, so we get a repeatable sequence.
// Note: AddEntropy can be called any number of times.
$fortuna->AddEntropy('01020304', 'hex');
$fortuna->AddEntropy('hello world', 'ascii');

// Generate some random data:
$strRandHex = $fortuna->GenRandom(16, 'hex');
$strRandBase64 = $fortuna->GenRandom(22, 'base64');
$strRandBase58 = $fortuna->GenRandom(32, 'base58');

echo 'hex random bytes: ', $strRandHex, "\n";
echo 'base64 random bytes: ', $strRandBase64, "\n";
echo 'base58 random bytes: ', $strRandBase58, "\n";

// Try it again with a different object to verify that the same results are obtained:
$fortuna2 = new Prng();

$fortuna2->AddEntropy('01020304', 'hex');
$fortuna2->AddEntropy('hello world', 'ascii');

$strRandHex = $fortuna2->GenRandom(16, 'hex');
$strRandBase64 = $fortuna2->GenRandom(22, 'base64');
$strRandBase58 = $fortuna2->GenRandom(32, 'base58');

echo 'hex random bytes: ', $strRandHex, "\n";
echo 'base64 random bytes: ', $strRandBase64, "\n";
echo 'base58 random bytes: ', $strRandBase58, "\n";