- substr: documentation ( source)
- hash: documentation ( source)
- hexdec: documentation ( source)
<?php
$server_seed = "d8b710dfa2c8a3d990ca1dc7cc0a91754ac20aa6139fb7f6d44b58ee31ece8dc";
$round_id = "27632";
$hash = hash("sha256",$server_seed."-".$round_id);
$roll = hexdec(substr($hash,0,8)) % 15;
echo "Round $round_id = $roll";