Cryptographic protocol flaws: know your enemy

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.<>