Paper 2025/296

DFS: Delegation-friendly zkSNARK and Private Delegation of Provers

Yuncong Hu, Shanghai Jiao Tong University
Pratyush Mishra, University of Pennsylvania
Xiao Wang, Northwestern University
Jie Xie, Shanghai Jiao Tong University
Kang Yang, State Key Laboratory of Cryptology
Yu Yu, Shanghai Jiao Tong University
Yuwen Zhang, UC Berkeley
Abstract

Zero-Knowledge Succinct Non-interactive Arguments of Knowledge (zkSNARKs) lead to proofs that can be succinctly verified but require huge computational resources to generate. Prior systems outsource proof generation either through public delegation, which reveals the witness to the third party, or, more preferably, private delegation that keeps the witness hidden using multiparty computation (MPC). However, current private delegation schemes struggle with scalability and efficiency due to MPC inefficiencies, poor resource utilization, and suboptimal design of zkSNARK protocols. In this paper, we introduce DFS, a new zkSNARK that is delegation-friendly for both public and private scenarios. Prior work focused on optimizing the MPC protocols for existing zkSNARKs, while DFS uses co-design between MPC and zkSNARK so that the protocol is efficient for both distributed computing and MPC. In particular, DFS achieves linear prover time and logarithmic verification cost in the non-delegated setting. For private delegation, DFS introduces a scheme with zero communication overhead in MPC and achieves malicious security for free, which results in logarithmic overall communication; while prior work required linear communication. Our evaluation shows that DFS is as efficient as state-of-the-art zkSNARKs in public delegation; when used for private delegation, it scales better than previous work. In particular, for constraints, the total communication of DFS is less than KB, while prior work incurs GB, which is linear to the circuit size. Additionally, we identify and address a security flaw in prior work, EOS (USENIX'23).

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Published elsewhere. Minor revision. USENIX Security 2025
Keywords
zero-knowledge proofsmulti-party computationsdistributed computations
Contact author(s)
huyuncong @ sjtu edu cn
prat @ seas upenn edu
wangxiao @ northwestern edu
xiejie1006 @ gmail com
yangk @ sklc org
yyuu @ sjtu edu cn
yuwen01 @ berkeley edu
History
2025-04-01: revised
2025-02-20: received
See all versions
Short URL
https://ia.cr/2025/296
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2025/296,
      author = {Yuncong Hu and Pratyush Mishra and Xiao Wang and Jie Xie and Kang Yang and Yu Yu and Yuwen Zhang},
      title = {{DFS}: Delegation-friendly {zkSNARK} and Private Delegation of Provers},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/296},
      year = {2025},
      url = {https://eprint.iacr.org/2025/296}
}
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