Abstract: Receiving a transaction authorization request by an authorization system from an Automated Teller Machine (ATM), wherein the transaction request includes at least transaction details, identifying information and an authentication code, and wherein the authentication code is generated by software in the possession of a user requesting said transaction request; forwarding the identifying information and the authentication code to an authentication server which shares authentication secrets in common with the software; receiving authentication results of the authentication, and authorizing the transaction request in accordance with the received results.