final class HexSHA512 {
    public static final function Hash($s) {
        return (bin2hex(hash('sha512', $s.bin2hex($s), true)));
    }
    public static final function Verify($s, $h) {
        return (HexSHA512::Hash($s) == $h);
    }
}

$s = "hello there";
$h = HexSHA512::Hash($s);
var_dump($h);
var_dump(HexSHA512::Verify($s, $h));