GFGiacomo Fenzi
00EPFL · COMPSEC Lab

PhD student · Cryptography · Proof systems

Hi! I am Giacomo, a PhD student at EPFL, where I am lucky enough to be supervised by Alessandro Chiesa.

My research is on cryptography and theoretical computer science, focusing on proof systems.

Interaction and randomness allow to trustlessly outsource computation and check its correctness with resources exponentially smaller than the original computation. In conjunction with cryptography, these proof systems lead to protocols called zkSNARKs, which play a central role in a number of applications, such as blockchain L2-rollups, anonymous credentials, signatures and more.

I study how to make zkSNARKs that are theoretically and concretely efficient, from post-quantum cryptographic primitives.

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01Papers

Publications

Selected publications

01

STIR 🥣

Reed-Solomon IOPP with fewer queries. Best Paper @ CRYPTO 2024

ePrintBlog post
02

WHIR 🌪️

Constrained RS IOPP with fewer queries and super-fast verification.

ePrintBlog post
04

ZO0K 🦓

Zero-Knowledge IOPPs with Zero-Overhead.

ePrint
05

TensorSwitch 🧮

Nearly-optimal polynomial commitment scheme from tensor codes.

ePrint
06

WARP 🌀

A linear time accumulation scheme from any linear code.

ePrint
07

UC-secure zkSNARKs 🌍

Commonly deployed zkSNARKs are UC-secure in the ROM.

ePrintBlog post
08

SLAP 👋

Succinct lattice-based polynomial commitment scheme from SIS.

ePrintBlog post

Full list of publications

2026

[BFRW26]

“TensorSwitch: Nearly Optimal Polynomial Commitments from Tensor Codes”.

Benedikt Bünz, Giacomo Fenzi, Ron D. Rothblum, William Wang.

CRYPTO 2026 & ZKProof 8. Available at: 2025/2065.

[FGV26]

“Finding Bugs and Features Using Cryptographically-Informed Functional Testing”.

Giacomo Fenzi, Jan Gilcher, Fernando Virdia.

RWC 2026 & TCHES 2026. Available at: 2024/1122.

[ACFY26]

“Interactive Proofs for Batch Polynomial Evaluation”.

Gal Arnon, Alessandro Chiesa, Giacomo Fenzi, Eylon Yogev.

ITC 2026. Available at: 2026/448.

[ABF26]

“Open Problems in List Decoding and Correlated Agreement”.

Gal Arnon, Dan Boneh, Giacomo Fenzi.

Available at: 2026/680.

[CFW26]

“Zero-Knowledge IOPPs for Constrained Interleaved Codes”.

Alessandro Chiesa, Giacomo Fenzi, Guy Weissenberg.

ZKProof 8. Available at: 2026/391.

[BFMM26]

“Field-Agnostic SNARKs with Small Proofs via Encode-Repeat-Accumulate (ERA) Codes”.

Anubhav Baweja, Giacomo Fenzi, Pratyush Mishra, Tushar Mopuri.

Cryptology ePrint Archive, Paper 2026/864. Available at: 2026/864.

2025

[ACFY25]

“WHIR: Reed–Solomon Proximity Testing with Super-Fast Verification”.

Gal Arnon, Alessandro Chiesa, Giacomo Fenzi, Eylon Yogev.

EUROCRYPT 2025 & zkSummit12. Available at: 2024/1586. Accompanying blog-post.

[BCFW25]

“Linear Time Accumulation Schemes”.

Benedikt Bünz, Alessandro Chiesa, Giacomo Fenzi, William Wang.

TCC 2025 & CAW 2025 & zkSummit13 & ZKProof 8. Available at: 2025/753.

[BCFFMMZ25]

“Time-space trade-offs for the sumcheck protocol”.

Anubhav Baweja, Alessandro Chiesa, Elisabetta Fedele, Giacomo Fenzi, Pratyush Mishra, Tushar Mopuri, Andrew Zitek-Estrada.

TCC 2025 & ZKProof 8. Available at: 2025/1473.

[CFFZ25]

“A Time-Space Tradeoff for the Sumcheck Prover”.

Alessandro Chiesa, Elisabetta Fedele, Giacomo Fenzi, Andrew Zitek-Estrada.

TCC 2025 & ZKProof 6. Available at: 2024/524. Accompanying blog-post.

[ABDFKKZ25]

“Post-Quantum Access Control with Application to Secure Data Retrieval”.

Behzad Abdolmaleki, Hannes Blümel, Tianxiang Dai, Giacomo Fenzi, Homa Khajeh, Stefan Köpsell, Maryam Zarezadeh.

Communications in Cryptology 2025.

[FS25]

“Small-field hash-based SNARGs are less sound than conjectured”.

Giacomo Fenzi, Antonio Sanso.

Cryptology ePrint Archive, Paper 2025/2197. Available at: 2025/2197.

[FZ25]

“zip: Reducing Proof Sizes for Hash-Based SNARGs”.

Giacomo Fenzi, Yuwen Zhang.

Cryptology ePrint Archive, Paper 2025/1446. Available at: 2025/1446.

2024

[ACFY24]

“STIR: Reed–Solomon Proximity Testing with Fewer Queries”.

Gal Arnon, Alessandro Chiesa, Giacomo Fenzi, Eylon Yogev.

CRYPTO 2024 (⭐️ Best Paper ⭐️) & zkSummit11 & ZKProof 6. Available at: 2024/390. Accompanying blog-post.

[CF24]

“zkSNARKs in the ROM with Unconditional UC-Security”.

Alessandro Chiesa, Giacomo Fenzi.

TCC 2024 & ZKProof 6. Available at: 2024/724. Accompanying blog-post.

[FKNP24]

“Lova: Lattice-Based Folding Scheme from Unstructured Lattices”.

Giacomo Fenzi, Christian Knabenhans, Khanh Ngoc Nguyen, Duc Tu Pham

ASIACRYPT 2024. Available at: 2024/1964.

[AFLN24]

“SLAP: Succinct Lattice-Based Polynomial Commitments from Standard Assumptions”.

Martin R. Albrecht, Giacomo Fenzi, Oleksandra Lapiha, Ngoc Khanh Nguyen.

EUROCRYPT 2024 & ZKProof 6. Available at: 2023/1469. Accompanying blog-post. Slides.

[FMN24]

“Lattice-Based Polynomial Commitments: Towards Concrete and Asymptotical Efficiency”.

Giacomo Fenzi, Hossein Moghaddas, Ngoc Khanh Nguyen.

Journal of Cryptology 2024 & ArticCrypt 2025. Available at: 2023/846. Accompanying blog-post.

02Talks

Upcoming / Past

Talks

Upcoming

2026

  1. Presenting ZO0K 🦓 at zkSummit.

  2. Organizing IOPFest.

  3. Presenting ZO0K 🦓 at ZKProof.

  4. Presenting Polylogarithmic Proofs for Multilinears over Binary Towers at EUROCRYPT26.

  5. Attending Cedarcrypt.

Past

2026

  1. Presented WHIR 🌪️ at Starkware.

  2. Presented WHIR 🌪️ at Aztec.

2025

  1. Presented Small-field hash-based SNARGs are less sound at Ethproofs.

  2. Presented Proximity Prize at Ethproofs.

  3. Presented WARP 🌀 at Swiss Crypyo Day.

  4. Attended the EF summit on PQ interop.

  5. Presented at Google: ZK & AI Summit.

  6. Attended Cryptography: 10 Years Later. at Simons

  7. Presented towards lattice based polynomial commitments at ArticCrypt25.

  8. Presented a survey on efficient succinct arguments at Cryptography: 10 Years Later at Simons.

  9. Presented WARP 🌀 at Stanford.

  10. Presented WHIR 🌪️ at EUROCRYPT25.

  11. Presented WARP 🌀 at CAW.

  12. Presented WHIR 🌪️ at Penn's Security and Privacy Lab.

  13. Presented WHIR 🌪️ at ZKProof7.

  14. Introduced the COMPSEC Lab at EDIC Open House.

  15. Presented Lova 💕 at ENSL/CWI/KCL/IRISA Joint Online Cryptography Seminars.

  16. Presented WHIR 🌪️ at RWC Paris.

2024

  1. Presented UC-secure zkSNARKs🌍 at TCC24.

  2. Presented WHIR 🌪️ at IBM Research Zurich.

  3. Presented WHIR 🌪️ at Nexus speaker series and sumcheck builder group.

  4. Presented UC-secure zkSNARKs🌍, STIR 🥣 and WHIR 🌪️ at BSA EPFL.

  5. Presented STIR 🥣 at Nexus speaker series and sumcheck builder group.

  6. Presented STIR 🥣 at TUM Blockchain Conference.

  7. Presented STIR 🥣 at Swiss Crypyo Day.

  8. Presented STIR 🥣 at CRYPTO24.

  9. Visiting Khanh at KCL.

  10. Presented STIR 🥣 at Starkitecture.

  11. Presented SLAP 👋 at EUROCRYPT24.

  12. Presented STIR 🥣, SLAP 👋, UC-secure zkSNARKs🌍 and Blendy 🍹 at ZKProof6.

  13. Presenting STIR 🥣 at zkSummit11.

  14. Presented UC-secure zkSNARKs🌍 at NYU.

  15. Presented UC-secure zkSNARKs🌍 at Penn.

  16. Presented UC-secure zkSNARKs🌍 at BUSec.

2023

  1. Presented SLAP 👋 at CWI.

03Writing

Accompanying posts

Writing

EUROCRYPT 2025 - ePrint: 2024/1586

WHIR: Reed–Solomon Proximity Testing with Super-Fast Verification

Gal Arnon, Alessandro Chiesa, Giacomo Fenzi, Eylon Yogev

We present WHIR (Weights Help Improving Rate), an interactive oracle proof of proximity (IOPP) for constrained Reed–Solomon codes. WHIR doubles as a multilinear polynomial commitment scheme, achieving the fastest verification speed of any such scheme while mantaining state-of-the-art argument size, verifier hash complexity and prover times.

hashesconcretetheory
TCC 2024 - ePrint: 2024/724

zkSNARKs in the ROM with Unconditional UC-Security

Alessandro Chiesa, Giacomo Fenzi

We show that commonly deployed zkSNARKs are UC-secure in the ROM, with no modifications needed.

concretetheory
CRYPTO 2024 - ePrint: 2024/390

STIR: Reed–Solomon Proximity Testing with Fewer Queries

Gal Arnon, Alessandro Chiesa, Giacomo Fenzi, Eylon Yogev

We present STIR (Shift To Improve Rate), a concretely efficient interactive oracle proof of proximity (IOPP) for Reed–Solomon codes that achieves the best known query complexity of any concretely efficient IOPP for this problem.

hashesconcretetheory
ePrint: 2024/524

A Time-Space Tradeoff for the Sumcheck Prover

Alessandro Chiesa, Elisabetta Fedele, Giacomo Fenzi, Andrew Zitek-Estrada

We present a new family of algorithms for the sumcheck protocol prover that offer new time-space tradeoffs.

sumcheckconcrete
EUROCRYPT 2024 - ePrint: 2023/1469

SLAP: Succinct Lattice-Based Polynomial Commitments from Standard Assumptions

Martin R. Albrecht, Giacomo Fenzi, Oleksandra Lapiha, Ngoc Khanh Nguyen

In this paper, we construct a succinct polynomial commitment scheme from standard assumptions.

latticespolynomial-commitmentstheory
JoC 2024 - ArticCrypt 2025 - ePrint: 2023/846

Lattice-Based Polynomial Commitments: Towards Asymptotic and Concrete Efficiency

Giacomo Fenzi, Hossein Moghaddas, Ngoc Khanh Nguyen

In this paper, we introduce the powerBASIS assumption, and use it construct quasi-succinct polynomial commitment schemes from lattices.

latticespolynomial-commitmentstheory

Blurbs

Blurbs

Short blurbs, tips and tricks that didn't find space in the papers or blog posts.

Doing mixed matrix commitments (MMCS) with STIR & WHIR

Giacomo Fenzi

Domain shifting to the rescue

hashesconcretetheory

LDPC codes vs RS codes

Giacomo Fenzi

Some thoughts on LDPC codes vs RS codes

hashesconcretetheory

Speeding up fold computation

Giacomo Fenzi

Computing folds is a large portion of the verifier work in schemes like FRI, STIR and WHIR. We describe an optimization to reduce this cost.

hashesconcrete

STIR: Setting Parameters

Giacomo Fenzi

STIR has a few more parameters to tweak compared to FRI. Here we mention a few and how they impact the concrete performance of the scheme.

hashesconcretetheory