- bin2hex: documentation ( source)
- base64_decode: documentation ( source)
<?php
$a = 'MEYCIQDuYdPrKDzmO1AZanczu09PsmTb7Oy9UcazdtTlntgTrwIhAPrR5tBqZiNi915ucWM1/Hhfh2insuwQEUI1KwtjQgVp';
$b = 'QURCR0FpRUE3bUhUNnlnODVqdFFHV3AzTTd0UFQ3SmsyK3pzdlZIR3MzYlU1WjdZRTY4Q0lRRDYwZWJRYW1Zall2ZGVibkZqTmZ4NFg0ZG9wN0xzRUJGQ05Tc0xZMElGYVE9PQ==';
echo bin2hex(base64_decode($a));
echo PHP_EOL;
echo bin2hex(base64_decode(base64_decode($b)));