We consider a secrecy property in a simple process calculus with cryptographic primitives. The standard Dolev-Yao attacker is enhanced so that it can guess the key for decrypting an intercepted message. We borrow from the computational complexity approach to secrecy the assumptions that guessing succeeds with a given negligible probability and that the resources available to attackers are polynomially bound. Under these hypotheses we prove that the standard Dolev-Yao attacker is as powerful as the enhanced one.
Finally, REF compares the classical Dolev-Yao adversary with an enhanced computational adversary which can guess the key for decrypting an intercepted message (albeit only with negligible probability).
A Note on the Perfect Encryption Assumption in a Process Calculus
FoSSaCS
Computer Science