Method and device for identification and authentication

A mobile electronic transaction device for identification and authentication of a holder of the device in an electronic transaction process between a transaction service provider and a transaction terminal in communication via a computer network, said mobile transaction device having contained therein:

• transceiver means for transmitting information to and receiving information from said transaction terminal, data input means, data processing means, data storage means for storing information including an externally accessible device identity, a non-retrievable reference user identification, and including a non-retrievable secret key to be processed by said processing means and used in communication with the service provider by said transceiver means over said network via the transaction terminal for validating a transaction, and means supplying electric energy to the device;
• wherein said transceiver means being adapted for transmitting the device identity to the transaction terminal and receiving a challenge transaction identifier from the service provider via the transaction terminal;
• said processing means being adapted for determining an authenticity of a user identification input by comparison with said reference user identification, and for performing a cryptographic transformation of the transaction identifier using said secret key only on said identification input being determined as authentic;
• and
• said transceiver means also being adapted for transmitting a response result of said cryptographic transformation to the service provider via said transaction terminal for validating said transaction.