Authenticating a transaction using an authentication code derived from a seed on a SIM

摘要

The user's SIM 20 is adapted to store a seed for generating an authentication code which is usable to authenticate a transaction. The mobile telecommunications device 1 has a processor including means operable to obtain the seed from the SIM, to calculate the authentication code and to generate a transaction message for enabling the transaction with the entity, the transaction message including the authentication code.