- hash_hmac: documentation ( source)
- base64_encode: documentation ( source)
<?php
echo base64_encode(hash_hmac('sha256', 'qizJsGrCWWsWYfjWri/vwLGXO283MAuiM/UXWxyjlMKLWwiqo1MmS4GF6YEefUuOqun8wR35BVx20muv', 'a8fba3643be0d9b5c41e3108ef6010634a9f8f9b8b8fb85fd0185998f4917ca4', false));