- hash_hmac: documentation ( source)
<?php
$timestamp = 1408731998;
$nonce = 1000127305;
$domain = 'flixfling.com';
$method = 'app.login';
$hash = hash_hmac('sha256', $timestamp .';'.$domain .';'. $nonce .';'.$method, '63ae8627d1119113809c4c9a01d60e81', FALSE);