Modelling Attacker's Knowledge for Cascade Cryptographic Protocols

International audienceWe address the proof-based development of cryptographic protocols satisfying security properties. Communication channels are supposed to be unsafe. Analysing cryptographic protocols requires precise modelling of the attacker's knowledge. In this paper we use the event B modelling language to model the knowledge of the attacker for a class of cryptographic protocols called \textit{cascade protocols}. The attacker's behaviour conforms to the Dolev-Yao model. In the Dolev-Yao model, the attacker has full control of the communication channel, and the cryptographic primitives are supposed to be perfect