- substr: documentation ( source)
- base64_decode: documentation ( source)
- base64_encode: documentation ( source)
- preg_replace: documentation ( source)
<?php
$data = 'MIIBCAKCAQEAx9a8pYAiNaVt9PrwjQ+0cB6elLiGpcPQxkQckuPToObXVJcg2BSWG1M4XcH70oI3sCipPBDQiy1HvzHIvW96qAYsbXR5ouEnNNF9hRlV3hE4LPQhN/H8QIOd8lYrepHcO2dR9gYM6zCQg312C3SJl6Q6AZGaDI8saxv7cmU95wqK4Zfr
';
$data = preg_replace('#\s#', '', $data);
$data = base64_decode($data); +
$data = substr($data, 18+3+1, 141);
$data = base64_encode($data);
echo $data;