Practical Security Analysis of Zero-Knowledge Proof Circuits

As privacy-sensitive applications based on zero-knowledge proofs (ZKPs) gain increasing traction, there is a pressing need to detect vulnerabilities in ZKP circuits. This paper studies common vulnerabilities in Circom (the most popular domain-specific language for ZKP circuits) and describes a static analysis framework for detecting these vulnerabilities. Our technique operates over an abstraction called the circuit dependence graph (CDG) that captures key properties of the circuit and allows expressing semantic vulnerability patterns as queries over the CDG abstraction. We have implemented 9 different detectors using this framework and performed an experimental evaluation on over 258 circuits from popular Circom projects on Github. According to our evaluation, these detectors can identify vulnerabilities, including previouslyunknown ones, with high precision and recall.