Patent ID: 8898450

Claim:
A method for authenticating a client device for a data transaction between the client device and a server, the method comprising: in the client device, sending a request message to the server in accordance with a protocol at the application layer of a computer communication model; in the client device, receiving a response message in accordance with the protocol from the server that is responsive to the request message and that indicates that the request is denied for lack of authorization; in the client device, sending an authorization request to the server in accordance with the protocol and in response to the response message; in the client device, receiving an authorization challenge message from the server in accordance with the protocol wherein the authorization challenge message requests data representing one or more parts of a digital fingerprint of the client device; in the client device, sending a challenge response message to the server in accordance with the protocol wherein the challenge response message includes data representing the one or more parts of a digital fingerprint of the client device; and in the client device, receiving a grant message from the server in accordance with the protocol only if the one or more parts of a digital fingerprint of the client device match predetermined data stored within the server representing the one or more parts of a digital fingerprint of an authorized client device; wherein the grant message represents a granting of the request of the request message by the server.