Interleaving Command Sequences: a Threat to Secure Smartcard Interoperability
The increasingly widespread use of smartcards for a variety of sensitive applications, including digital signatures, creates the need to ensure and possibly certify the secure interoperability of these devices. Standard certification criteria, in particular the Common Criteria, define security requirements but do not sufficiently address the problem of interoperability. Here, the authors consider the interoperability problem which arises when various applications interact with different smartcards through a middleware. In such a situation it is possible that a smartcard of type S receives commands that were supposed to be executed on a different smartcard of type. Such "External commands" can interleave with the commands that were supposed to be executed on S.