Computational Semantics of a Verification Logic of Local Sessions

We propose a computational semantics for a previously developed protocol security logic, Logic of Local Sessions (LLS), replacing its earlier symbolic semantics based on the Dolev-Yao model. With the new semantics, the protocol verification of LLS is more close to the real execution, while the proofs can still be carried out at a symbolic level using the original proof system and the automatic verification tool. Our results hold under standard cryptographic assumptions.