Mobile codes with interactive proofs: an approach to provably safe evolution of distributed software systems

Abstract

This paper proposes a new proof-based approach to safe evolution of distributed software systems. Specifically it extends the simple certification mechanism of proof-carrying code (PCC) to make it interactive and probabilistic, thereby devising code with interactive proof (CIP). With CIP, a code consumer is convinced, with overwhelming probability, of the existence and validity of a safety proof of a transmitted code through interaction with a code producer. The class of safety properties that are provable by CIP is larger than the class provable by PCC, provided that each code consumer is allowed to spend a reasonable amount of time on verification. Moreover, CIP can be further extended to devise code with zero-knowledge interactive proof (CZKIP). This concept is useful, for example, when the code producer wants to use the safety proof as a kind of "copyright" of the code.