The transaction authentication number (TAN) is a unique code that is generated by a bank or other financial institution for each transaction you make. It is typically used as an extra layer of security to protect you from fraud.

Purpose:

• To prevent unauthorized transactions on your account.
• To ensure that you are the authorized user of the account.
• To provide additional security for online and mobile banking.

How it works:

1. TAN Generator: Your bank provides you with a TAN generator, which can be a physical device, a software application, or even your mobile phone.
2. Generating the TAN: To initiate a transaction, you use the TAN generator to generate a unique TAN for that transaction.
3. TAN Authentication: The TAN is then entered into the online banking system along with your account information and other required details. The bank verifies the TAN with your account and the TAN generator. If the TAN is valid, the transaction is approved.

Types of TAN:

• Static TAN: This TAN is generated once and can be used for multiple transactions within a specific timeframe.
• Dynamic TAN: This TAN changes for each transaction and is generated anew for each transaction.

Examples:

• Online shopping: You provide your bank card information and TAN when you checkout online.
• Mobile banking: You use your TAN to authorize transactions on your mobile banking app.
• Transferring money: You use your TAN to authorize money transfers between your accounts.

Benefits:

• Reduced fraud: The TAN makes it much more difficult for scammers to commit fraud, as they would need to possess your TAN generator or hijack your device.
• Increased security: The TAN adds an extra layer of security to your account, even if your passwords are compromised.
• Convenience: TAN generators are generally easy to use and can be readily available on your phone or at your bank.

Additional notes:

• The TAN is not stored on your bank’s server. It is generated on your device and sent to the bank in a secure manner.
• You should never share your TAN with anyone. If you suspect that your TAN has been compromised, you should contact your bank immediately.