ParagonIE_Sodium_Core_Poly1305::onetimeauth_verify

    public static function onetimeauth_verify($mac, $m, $key)
    {
        if (self::strlen($key) < 32) {
            throw new InvalidArgumentException(
                'Key must be 32 bytes long.'
            );
        }
        $state = new ParagonIE_Sodium_Core_Poly1305_State(
            self::substr($key, 0, 32)
        );
        $calc = $state
            ->update($m)
            ->finish();
        return self::verify_16($calc, $mac);
    }