- substr: documentation ( source)
- var_dump: documentation ( source)
- password_verify: documentation ( source)
- md5: documentation ( source)
<?php
$hash = '$md5$2y$10$atGASXMlANJI2CUyCQqZEeOB6cPxXD8NxTa9E/sQTxfGL7Du9WDyi';
var_dump(substr($hash, 0, 4) === '$md5');
var_dump(password_verify(md5('test'), substr($hash, 4)));