Patent ID: 7810165

Claim:
A portable consumer device comprising: a memory on which dynamic authentication data is stored; a processor configured to update the dynamic authentication data; a read-write device configured to read data from the memory and write data onto the memory; and an interface for transmitting data from the portable consumer device and receiving power from an external device, wherein each and every time power is received from the external device the portable consumer device is configured to: read the dynamic authentication data from the memory using the read-write device, generate updated dynamic authentication data using the processor, write the updated dynamic authentication data to the memory using the read-write device, and transmit the updated dynamic authentication data from the portable consumer device to the external device, and wherein the power received each and every time from the external device for operating the processor and the read-write device is received exclusively from the external device, and wherein the power received from the external device is temporarily stored in an energy storage means of the portable consumer device, and wherein the temporarily stored power is used up at the end of an authentication transaction, and wherein the dynamic authentication data comprises at least one of an automatic transaction counter and a dynamic card verification value.