Paper 2025/302 Original: eprint.iacr.org/2025/302 ↗
Phalanx: An FHE-Friendly SNARK for Verifiable Computation on Encrypted Data
Abstract
Verifiable Computation over encrypted data (VCoed) has two popular paradigms: SNARK-FHE (applying SNARKs to prove FHE operations) and FHE-SNARK (homomorphically evaluating SNARK proofs). For the existing works, FHE-SNARK has a much better efficiency compared to SNARK-FHE. In this work, we follow the line of FHE-SNARK and further improve its efficiency by designing Phalanx—an FHE-friendly SNARK that is: a) 3× lower multiplicative depth than FRI-based SNARKs; and b) Compatible with FHE SIMD operations. Based on Phalanx, we construct an FHE-SNARK scheme that has: a) $7.3×\sim 24.4×$ speedup: 2.27-hour proof generation for $2^{20}$-gate circuits on a single core CPU and 0.68-hour when the input ciphertexts are in iNTT form (vs. 16.57 hours in the state-of-the-art); and b) Practical verification: 61.4 MB proofs with 2.8 seconds verification (single core).
Metadata
- Available format(s)
PDF- Category
- Cryptographic protocols
- Publication info
- Preprint.
- History
- 2025-10-19: last updated
- 2025-02-20: published
- Short URL
- https://ia.cr/2025/302
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2025/302,
author = {Xinxuan Zhang and Ruida Wang and Zeyu Liu and Binwu Xiang and Yi Deng and Ben Fisch and Xianhui Lu},
title = {Phalanx: An FHE-Friendly SNARK for Verifiable Computation on Encrypted Data},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/302},
year = {2025},
url = {https://eprint.iacr.org/2025/302}
}