The TAN-methodology (TAN standing for “Transaction Number”) is a payment process in online or mobile banking that ensures extra security. Apart from the entry recognition (generally user name or the dial-up account) and a PIN it sees to a safe execution of transactions. TANs are one-time passwords with six to eight numbers. Some time ago, the lists were sent by post, today they are sent as an SMS, an integrated chip in the banking card which is read by a special reading device and the pushTAN sending the TAN to an app on the mobile.