Security Analysis of Micali's Fair Contract Signing Protocol by Using Coloured Petri Nets

In this paper, we present a systematic method to analyze the security of Micalipsilas fair contract signing protocol by using coloured Petri nets (CPN). By using CPN, we found two new attacks in the protocol. Also, we show that Baopsilas improved version of the protocol is secure against known message replay attacks on Micalipsilas protocol and our new attacks.