Acrónimo: TAN
Número
singular que sólo se utiliza una vez para identificar una transacción y
autenticarla.
A Transaction authentication
number, TAN or T.A.N. is used by some online banking services as a form of
single use one-time passwords to authorize financial transactions. TANs are a
second layer of security above and beyond the traditional single-password
authentication.
TANs are believed to provide
additional security because they act as a form of two-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 TAN.
http://en.wikipedia.org/wiki/Transaction_authentication_number