SAPIC+: protocol verifiers of the world, unite!

Symbolic security protocol verifiers have reached a high degree of automation and maturity. Today, experts can model real-world protocols, but this often requires model-specific encodings and deep insight into the strengths and weaknesses of each of those tools. With SAPIC+, we introduce a protocol verification platform that lifts this burden and permits choosing the right tool for the job, at any development stage. We build on the existing compiler from SAPIC to TAMARIN, and extend it with automated translations from SAPIC+ to PROVERIF and DEEPSEC, as well as powerful, protocol-independent optimizations of the existing translation. We prove each part of these translations sound. A user can thus, with a single SAPIC+ file, verify reachability and equivalence properties on the specified protocol, either using PROVERIF, TAMARIN or DEEPSEC. Moreover, the soundness of the translation allows to directly assume results proven by another tool which allows to exploit the respective strengths of each tool. We demonstrate our approach by analyzing various existing models. This includes a large case study of the 5G authentication protocols, previously analyzed in TAMARIN. Encoding this model in SAPIC+ we demonstrate the effectiveness of our approach. Moreover, we study four new case studies: the LAKE-EDHOC and the Privacy-Pass protocols, both under standardization, the SSH protocol with the agent-forwarding feature, and the recent KEMTLS protocol, a post-quantum version of the main TLS key exchange.