International Association
for Cryptologic Research

This paper introduces Sigmabus, a technique designed to enhance the efficiency of zero-knowledge circuits by relocating computationally expensive operations outside the circuit. Specifically, Sigmabus focuses on moving elliptic curve group operations, typically proven with expensive non-native field arithmetic, to external computations. By leveraging Sigma protocols, elliptic curve group operations are proven outside the circuit, while additional constraints are applied to the circuit to ensure correct execution of the Sigma protocol. This approach can achieve significant performance improvements in zero-knowledge circuits. This paper presents the Sigmabus protocol along with its security proofs, and demonstrates its practical implications through various use cases.