Instead of using the [encrypt and decrypt functions](https://github.com/digitalutsc/arks-service/blob/59b111396203df948bc5076cbd8a52bc5d13a7be/admin/functions.php#L56) the password should be hashed using [password_hash](https://www.php.net/manual/en/function.password-hash.php) and then checked for a match, using [password_verify](https://www.php.net/manual/en/function.password-verify.php)