Problem
Zero-knowledge proof systems have become critical infrastructure for blockchain scalability and privacy, with billions of dollars in value secured by their correctness. As the ecosystem evolves, increasingly complexzkVMs and recursive proof composition create a self-referential dependency: the verifier itself must be verified.
Approach
This 'Ouroboros of ZK' — the verifier verifying the verifier — poses a fundamental challenge to the long-term security of recursive proof systems. We argue that without rigorous verification of the verifier circuit, the soundness guarantees of the entire proof system rest on an unverified foundation.
Results
We propose a methodology for end-to-end verification of zkVM implementations, combining formal specification of the execution model with property-based testing of the proof system's soundness properties. Our approach identifies a class of vulnerabilities that arise specifically from recursive composition, where a verifier's acceptance of an invalid proof can be amplified through recursive layers. We demonstrate this methodology on a representative zkVM, discovering subtle soundness bugs that would not be caught by conventional testing.