Overview#

Transaction Authentication Number (TAN) is used by some online banking services as a form of single use One-Time passwords to authorize financial transactions.

Transaction Authentication Numbers provide additional security because they act as a form of Multi-Factor Authentication. Should the physical document or token containing the TANs be stolen, it will be of little use without the password; conversely, if the login data are obtained, no transactions can be performed without a valid Transaction Authentication Number.

Originally, Transaction Authentication Numbers were printed on a piece of paper and handed by the bank personnel to the end user. Now there are many different methods used for providing Transaction Authentication Numbers.

More Information#

There might be more information for this subject on one of the following:

• Mobile TAN
• SS7 hack
• TAN

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• [#1] - Transaction authentication number - based on information obtained 2015-10-30