A Novel Framework for Protocol Analysis

We describe a novel reformulation of Canetti’s Universal Composability (UC) framework for the analysis of cryptographic protocols. Our framework is different mainly in that it is (a) based on systems of interactive Turing machines with a fixed communication graph and (b) augmented with a global message queue that allows the sending of multiple messages per activation. The first feature significantly simplifies the proofs of some framework results, such as the UC theorem, while the second can lead to more natural descriptions of protocols and ideal functionalities. We illustrate how the theory can be used with several examples.