Patent ID: 8924713

Claim:
A method for authenticating a transaction or access via a security device, the method comprising: communicating an authentication request by the security device to an authentication server; for a sequence of information requests comprising a plurality of information requests: receiving an information request in the plurality of information requests at the security device from the authentication server; in response to the received information request, sending a response from the security device to the authentication server, the response comprising a value generated based on a current state in a plurality of states of an internal authentication state machine in the security device; and repeating said receiving and said sending for each information request in the plurality of information requests to traverse the authentication state machine until sending a response to a last information request in the sequence of information requests, wherein the values sent to the authentication server comprise a sequence of reported values, wherein the security device is authenticated by the authentication server based on comparing of the sequence of reported values with a sequence of expected values used by the authentication server in uniquely identifying the security device.