Protocol composition logic

Protocol Composition Logic is a formal method that can be used for proving security properties of cryptographic protocols that use symmetric-key and public-key cryptography. PCL is designed around a process calculus with actions for various possible protocol steps (e.g. generating random numbers, performing encryption, decryption and digital signature operations as well as sending and receiving messages).^[1]

Some problems with the logic have been found, implying that some currently claimed results cannot be proven within the logic.^[2]