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Emmanuela Orsini

@emmanuelaorsini.bsky.social

168 Followers  |  154 Following  |  3 Posts  |  Joined: 03.12.2023  |  1.5244

Latest posts by emmanuelaorsini.bsky.social on Bluesky


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Commission presents Roadmap for effective and lawful access to data for law enforcement The European Commission presented today a Roadmap setting out the way forward to ensure law enforcement authorities in the EU have effective and lawful access to data.

Well, this horrible idea refuses to die so we should refuse to let it pass and start organizing again.

ec.europa.eu/commission/p...

05.07.2025 17:25 — 👍 76    🔁 43    💬 2    📌 5
POTA: A Pipelined Oblivious Transfer Acceleration Architecture for Secure Multi-Party Computation | IACR Transactions on Cryptographic Hardware and Embedded Systems

Researchers at the Chinese Academy of Sciences implemented OT on FPGAs and made MASCOT up to 600 times faster: ojs.ub.rub.de/index.php/TC...

14.06.2025 04:21 — 👍 3    🔁 2    💬 0    📌 0

Join us for Theory Day 2025!

We’re hosting a one-day theory workshop at Bocconi featuring a great lineup of speakers covering exciting topics in TCS. Great opportunity to hear some fantastic talks and connect!

📅 June 17 2025 @ Bocconi University, Milan

20.05.2025 12:56 — 👍 2    🔁 1    💬 1    📌 0

Our paper on row reduction for multiparty garbling is finally out! It will be presented at Crypto 2025.

12.05.2025 07:42 — 👍 14    🔁 0    💬 2    📌 0
Abstract. Non-malleable zero-knowledge (NMZK), originally introduced in the seminal work of Dolev, Dwork, and Naor (STOC 91), is a fundamental concept for modeling the security of proof systems against man-in-the-middle attacks. Recently, Kim, Liang, and Pandey (CRYPTO 2022) presented the first efficient constant-round NMZK argument system based solely on symmetric-key cryptography. Their construction relies on a non-black-box use of the involved cryptographic primitives and on multiple executions of Ligero (CCS 2017) that affect both the round complexity and the computational efficiency of their protocol. Their work left open the natural important challenge of achieving NMZK using the underlying primitives only in a black-box fashion (regardless of the number of rounds and actual efficiency). In this paper, we solve the aforementioned open problem by presenting the first NMZK argument system based on the black-box use of cryptographic primitives. Our work is optimal in the use of primitives since we only need one-way functions, and asymptotically optimal in the number of rounds since we only require a constant number of rounds. Our argument system is non-malleable with respect to the strong “simulation-extractability” flavor of non-malleability. Furthermore, we also show that our construction can be efficiently instantiated in Minicrypt, significantly improving upon the work of Kim et al., both in terms of round complexity and computational efficiency.

Abstract. Non-malleable zero-knowledge (NMZK), originally introduced in the seminal work of Dolev, Dwork, and Naor (STOC 91), is a fundamental concept for modeling the security of proof systems against man-in-the-middle attacks. Recently, Kim, Liang, and Pandey (CRYPTO 2022) presented the first efficient constant-round NMZK argument system based solely on symmetric-key cryptography. Their construction relies on a non-black-box use of the involved cryptographic primitives and on multiple executions of Ligero (CCS 2017) that affect both the round complexity and the computational efficiency of their protocol. Their work left open the natural important challenge of achieving NMZK using the underlying primitives only in a black-box fashion (regardless of the number of rounds and actual efficiency). In this paper, we solve the aforementioned open problem by presenting the first NMZK argument system based on the black-box use of cryptographic primitives. Our work is optimal in the use of primitives since we only need one-way functions, and asymptotically optimal in the number of rounds since we only require a constant number of rounds. Our argument system is non-malleable with respect to the strong “simulation-extractability” flavor of non-malleability. Furthermore, we also show that our construction can be efficiently instantiated in Minicrypt, significantly improving upon the work of Kim et al., both in terms of round complexity and computational efficiency.

Image showing part 2 of abstract.

Image showing part 2 of abstract.

Black-Box (and Fast) Non-Malleable Zero Knowledge (Vincenzo Botta, Michele Ciampi, Emmanuela Orsini, Luisa Siniscalchi, Ivan Visconti) ia.cr/2025/432

06.03.2025 22:35 — 👍 3    🔁 1    💬 0    📌 0

Check out FAEST updates. Thank you to all the team!!

25.02.2025 18:04 — 👍 3    🔁 0    💬 0    📌 0
Abstract. The use of MPC-in-the-Head (MPCitH)-based zero-knowledge proofs of knowledge (ZKPoK) to prove knowledge of a preimage of a one-way function (OWF) is a popular approach towards constructing efficient post-quantum digital signatures. Starting with the Picnic signature scheme, many optimized MPCitH signatures using a variety of (candidate) OWFs have been proposed. Recently, Baum et al. (CRYPTO 2023) showed a fundamental improvement to MPCitH, called VOLE-in-the-Head (VOLEitH), which can generically reduce the signature size by at least a factor of two without decreasing computational performance or introducing new assumptions. Based on this, they designed the FAEST signature which uses AES as the underlying OWF. However, in comparison to MPCitH, the behavior of VOLEitH when using other OWFs is still unexplored. In this work, we improve a crucial building block of the VOLEitH and MPCitH approaches, the so-called all-but-one vector commitment, thus decreasing the signature size of VOLEitH and MPCitH signature schemes. Moreover, by introducing a small Proof of Work into the signing procedure, we can improve the parameters of VOLEitH (further decreasing signature size) without compromising the computational performance of the scheme. Based on these optimizations, we propose three VOLEitH signature schemes FAESTER, KuMQuat, and MandaRain based on AES, MQ, and Rain, respectively. We carefully explore the parameter space for these schemes and implement each, showcasing their performance with benchmarks. Our experiments show that these three signature schemes outperform MPCitH-based competitors that use comparable OWFs, in terms of both signature size and signing/verification time.

Abstract. The use of MPC-in-the-Head (MPCitH)-based zero-knowledge proofs of knowledge (ZKPoK) to prove knowledge of a preimage of a one-way function (OWF) is a popular approach towards constructing efficient post-quantum digital signatures. Starting with the Picnic signature scheme, many optimized MPCitH signatures using a variety of (candidate) OWFs have been proposed. Recently, Baum et al. (CRYPTO 2023) showed a fundamental improvement to MPCitH, called VOLE-in-the-Head (VOLEitH), which can generically reduce the signature size by at least a factor of two without decreasing computational performance or introducing new assumptions. Based on this, they designed the FAEST signature which uses AES as the underlying OWF. However, in comparison to MPCitH, the behavior of VOLEitH when using other OWFs is still unexplored. In this work, we improve a crucial building block of the VOLEitH and MPCitH approaches, the so-called all-but-one vector commitment, thus decreasing the signature size of VOLEitH and MPCitH signature schemes. Moreover, by introducing a small Proof of Work into the signing procedure, we can improve the parameters of VOLEitH (further decreasing signature size) without compromising the computational performance of the scheme. Based on these optimizations, we propose three VOLEitH signature schemes FAESTER, KuMQuat, and MandaRain based on AES, MQ, and Rain, respectively. We carefully explore the parameter space for these schemes and implement each, showcasing their performance with benchmarks. Our experiments show that these three signature schemes outperform MPCitH-based competitors that use comparable OWFs, in terms of both signature size and signing/verification time.

Image showing part 2 of abstract.

Image showing part 2 of abstract.

One Tree to Rule Them All: Optimizing GGM Trees and OWFs for Post-Quantum Signatures (Carsten Baum, Ward Beullens, Shibam Mukherjee, Emmanuela Orsini, Sebastian Ramacher, Christian Rechberger, Lawrence Roy, Peter Scholl) ia.cr/2024/490

27.03.2024 18:04 — 👍 3    🔁 3    💬 0    📌 0

The TCC '24 PC is up with the cfp

tcc.iacr.org/2024/

27.03.2024 16:16 — 👍 3    🔁 0    💬 0    📌 0

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