Affiliations: [a] Computer Laboratory, University of Cambridge, 15 JJ Thomson Avenue, Cambridge CB3 0FD, UK. E-mail: giampaolo.bella@cl.cam.ac.uk | [b] Dipartimento di Matematica e Informatica, Università di Catania, Viale A. Doria 6, I-95125 Catania, Italy. E-mail: giamp@dmi.unict.it
Abstract: An existing approach based on induction and theorem proving is tailored to the verification of security protocols that make use of smart cards. Smart cards are modelled operationally, hence only their functionalities, rather than their implementative technicalities, are of interest. The spy can steal certain smart cards, and clone others while learning their stored secrets. In terms of generality, the approach scales up to protocols that assume secure or insecure means between agents and smart cards, as well as to smart cards being PIN-operated or PIN-less. In terms of extensibility, new, application-dependent smart card functionalities can be easily included. The approach is demonstrated on the key distribution protocol designed by Shoup and Rubin [30], and the assumptions are studied that are necessary on the smart cards for the protocol goals to be met. It is found that, if the data buses of the smart cards are unreliable as to produce outputs in an unspecified order, then the protocol does not confirm to the peers its goals of confidentiality, authentication, and key distribution because of lack of explicitness. A simple fix is introduced and proved.
