1. A method comprising the steps of: deriving a base point on an elliptic curve in a first processing device; generating authentication information in the first processing device utilizing the base point and a private key of the first processing device; and transmitting the authentication information from the first processing device to a second processing device via a communications network; wherein the authentication information is utilized by the second processing device to generate modified authentication information suitable for providing joint authentication of the first and second processing devices to a verifying device; and wherein the verifying device jointly authenticates the first and second processing devices utilizing the modified authentication information.