- base64_decode: documentation ( source)
<?php
$encodedString = "RwBVAEkARAAgACgANwBmAGEAZAA4AGEANgBhAGEAOQA3ADAANAAwAGEAYgBiAGUAMQBiAGEAZQBjAGMAZgBiADgAMwA4AGEAMABkACkAIABuAG8AdAAgAGYAbwB1AG4AZAAgAGkAbgAgAFEAIAB0AGEAYgBsAGUALgA=";
$decodedString = base64_decode($encodedString);
echo $decodedString;