Flaws are introduced at every stage of the protocol development cycle. The engineer is faced with the problem of how to avoid them. The first step is to gain an understanding of the different flavours of cryptographic protocol flaws, i.e. get to know the enemy. This paper provides a classification of protocol flaws, including two new flaws in an application of the mental poker protocol, and discusses appropriate countermeasures for relevant flaw-categories.>

This paper describes a tool which translates a cryptographic protocol specified in the semi-formal standard notation i. A/spl rarr/B:M into the formal language CKT5. We examine the standard notation syntax, and describe how it is exploited by the tool to infer protocol conditions which must hold for every principal, thereby obtaining a complete, formal specification of the protocol. The translation criteria described herein are applicable to other target languages than CKT5.>

Vulnerabilities may be introduced at all stages of cryptographic protocol design. Reasoning about a protocol at a functional level does not unveil flaws which are inherently implementation-dependent. This paper uncovers a potential implementation-dependent flaw in a previously published protocol. Formal techniques should be able to analyse protocols with respect to such flaws. The epistemic logic CKT5 is modified and shown to operate at a sufficiently detailed bevel to capture implementation-dependent flaws.>