socrates1024

Abstract. Secure multi-party computation (MPC) enables N parties to jointly evaluate any function over their private inputs while preserving confidentiality. While decades of research have produced concretely efficient protocols for small to moderate numbers of participants, scaling MPC to thousands of parties remains a central challenge. Most of the existing approaches either incur per-party costs linear in N, due to pairwise computations, or rely on heavy cryptographic tools such as homomorphic encryption, which introduces prohibitive overheads when evaluating Boolean circuits. In this work, we introduce a new lightweight approach to designing semi-honest MPC protocols with per-party, per-gate computation and communication costs that are independent of N. Our construction leverages the Sparse Learning Parity with Noise (Sparse LPN) assumption in the random oracle model to achieve per-gate costs of O(k² ⋅ c(λ)) computation and O(c(λ)) communication, where k is the sparsity parameter for the Sparse LPN assumption and c(λ) is an arbitrarily small super-constant in the security parameter λ. Assuming Sparse LPN remains hard for any super-constant sparsity, this yields the first semi-honest MPC protocol in the dishonest-majority setting with per-party per-gate costs bounded by an arbitrarily small super-constant overhead in λ. Structurally, our MPC instantiates a Beaver style MPC with the required correlations generated efficiently. Departing from prior approaches that generate Beaver triples silently (Boyle et al., 2019; 2020; 2022) or using homomorphic computation (Damgård et al., 2012) for Beaver style MPC, the focus of this work rests on efficiently generating a weaker correlation. In particular, using Sparse LPN we show that if we relax the correctness requirement in generating random Beaver triples to permit a tunably small inverse-polynomial error probability, such triples can be silently generated with arbitrarily small super-constant per-party computation. We then show that such correlations can be used in an efficient online phase similar to Beaver’s protocol (with a tiny super-constant factor blow-up in communication).

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A New Approach to Large Party Beaver-Style MPC with Small Computational Overhead (Aayush Jain, Huijia Lin, Nuozhou Sun) ia.cr/2025/2305

Financial Cryptography

Final call for papers FC26
fc26.ifca.ai/cfp.html

Submission deadline: 20 September 2025

Conference:
2–6 March 2026
St. Kitts Marriott Resort

Abstract. Hashing to elliptic curve groups is a fundamental operation used in many cryptographic applications, including multiset hashing and BLS signatures. With the recent rise of zero-knowledge applications, they are increasingly used in constraint programming settings. For example, multiset hashing enables memory consistency checks in zkVMs, while BLS signatures are used in proof of stake protocols. In such cases, it becomes critical for hash-to-elliptic-curve-group constructions to be constraint-friendly such that one can efficiently generate succinct proofs of correctness. However, existing constructions rely on cryptographic hash functions that are expensive to represent in arithmetic constraint systems, resulting in high proving costs. We propose a constraint-efficient alternative: a map-to-elliptic-curve-group relation that bypasses the need for cryptographic hash functions and can serve as a drop-in replacement for hash-to-curve constructions in practical settings, including the aforementioned applications. Our relation naturally supports non-deterministic map-to-curve choices making them more efficient in constraint programming frameworks and enabling efficient integration into zero-knowledge proofs. We formally analyze the security of our approach in the elliptic curve generic group model (EC-GGM). Our implementation in Noir/Barretenberg demonstrates the efficiency of our construction in constraint programming: it achieves over 23× fewer constraints than the best hash-to-elliptic-curve-group alternatives, and, enables 50-100× faster proving times at scale.

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Constraint-Friendly Map-to-Elliptic-Curve-Group Relations and Their Applications (Jens Groth, Harjasleen Malvai, Andrew Miller, Yi-Nuo Zhang) ia.cr/2025/1503

Financial Cryptography '26 call for papers is up
fc26.ifca.ai/cfp.html

Paper submission deadline is September 16

Abstract. Atomic swaps enable asset exchanges across blockchains without relying on trusted intermediaries, and are a key component of decentralized finance (DeFi) ecosystems. Recently, Chung, Masserova, Shi, and Thyagarajan introduced Rapidash (Financial Cryptography 2025), an atomic swap protocol that remains incentive compatible under user-miner collusion, by ensuring that the honest strategy forms a coalition-resistant Nash equilibrium. However, their model assumes a closed system where players act solely based on internal protocol incentives. In practice, participants may be influenced by external incentives such as off-chain rewards or adversarial bribes, which can undermine such equilibrium guarantees. In this work, we introduce a new game-theoretic notion, bounded maximin fairness, which ensures that honest participants remain protected against rational adversaries with arbitrary but bounded external incentives. We construct an atomic swap protocol that satisfies this notion, while preserving the equilibrium properties of prior work in the absence of external influence. As we show, our protocol is easy to implement and can be instantiated even in Bitcoin’s limited scripting language.

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Fairness in the Wild: Secure Atomic Swap with External Incentives (Hao Chung, Elisaweta Masserova, Elaine Shi, Sri AravindaKrishnan Thyagarajan) ia.cr/2025/1086

Announcement post for Graze Grants (Beta) - we're funding new ATProto work, visit Graze.social (or really the link below in the next post) to apply

We've been given an amazing opportunity with our round of funding to build out the next generation of the social web. Today, we're starting an experiment in paying that forward. Introducing Graze Grants, a project to help get other ATProto projects off the ground.

I am definitely trying to automate cross-posting everywhere! how better to practice w diff platforms

I like racoons

River Bandit Wildlife Rescue

whenever I'm up early I make sure to send a lot of emails

cops have their own distinct verb tense... like "I'm gonna have to ask you to step out of the vehicle"

well go on then

what makes a good abstraction? (and other weird thoughts and tangents)

Blogpost here: lmao.bearblog.dev/minimal-abst...

pilots address the cabin "the winds are from the east at 3 knots and the cloud layer starts at 7000 feet" like that means anything to the passengers.

I think theyre just pretending to be so unselfaware as to think everyone else is as obsessed with the weather too, affected hyper focus

up late making slides for a conference that doesn't exist

good terminology clarity for people who are still confused by the idea of an "AppView"

Financial Cryptography 2025 begins now in Miyakojima fc25.ifca.ai

As such, we’re excited about this opportunity to put into practice the research ideas around individual and societal recommendation quality that our team has been thinking about (proceedings.neurips.cc/paper_files/..., dl.acm.org/doi/10.1145/...)

Our vision is state-of-the-art paper recommendation that takes the best of "social" (what made academic twitter great) and "content-based" (using modern NLP). Overtime, we will add (optional!) features using follower graph, interactions, text… Only possible using Bluesky algorithmic feed features

While right now the feed is based only on users you follow, over time we plan to build opt-in algorithmic recommendations to help you discover paper-related content matching your interests from across #academicsky

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firefly is kind of an "authentication methods" playground, android app is my favorite though

I get Frontera in Chicago it's pretty good. I'll cheers to you next time I go, asynchronous dinner party!

I'm not in Atlanta :D

Who was in charge of font spacing for this episode of MR. ED?

Beavis and Butt-Head go to Silent Hill

Carter has passed. An accomplished man. A brilliant legacy. Although for many of us he died years ago when he refused to condemn, gamer gate

"I contend that my knowledge is complete!"
"Per what?!?"
"Per Martin-Löf."

I've held punch cards in my hand, ha