public static function hashTransaction($transaction) {
        $salt = 'SALT';

        if ($salt != null) {

              $s = $salt . microtime() . $transaction->date . $transaction->description . $transaction->value;
              $hash = hash('sha512',$s,false);
        } else {
            throw new Exception("TransactionPersistance.hash_salt setting empty");
        }

        return $hash;
    }