Paper 2024/1405 Original: eprint.iacr.org/2024/1405 ↗

VECTIS: Efficient Batching Framework for Group-based CP-SNARKs

Abstract

Blockchain applications in finance and identity management increasingly require scalable and privacy-preserving solutions. Cryptographic commitments secure sensitive data on-chain, but verifying properties of these commitments efficiently remains challenging, particularly in large-scale scenarios. For multiple commitments, CP-SNARKs, a family of zk-SNARKs, enhance prover efficiency by shifting large-cost operations outside the circuit and verifying linkages between commitments, but incur verifier-side overhead due to linkage checks. Verification costs grow with the number of commitments, leading to inefficiencies in key size, proof size, and verification time. We propose $\textbf{VECTIS}$, an efficient batching framework for proving multiple commitments. Our approach aggregates multiple commitments into a single batched commitment, enabling the linking proof system to operate on the aggregated commitment instead of individual commitments, thereby significantly reducing the overall verification cost.%streamlining the verification process and improving efficiency. Experimental results show meaningful efficiency gains. For $2^{16}$ commitments, $\textbf{VECTIS}$ reduces the verification time to $0.064$s, achieving over $30\times$ improvement compared to LegoSNARK’s $1.972$s. These results show $\textbf{VECTIS}$’s potential for enabling scalable and efficient privacy-preserving solutions in blockchain applications.