ePrint Report: Secure Latent Dirichlet Allocation Thijs Veugen, Vincent Dunning, Michiel Marcus, Bart Kamphorst Topic modelling refers to a popular set of techniques used to discover hidden topics that occur in a collection of documents. These topics can, for example, be used to categorize documents or label text for further processing. One popular topic modelling technique is Latent Dirichlet Allocation (LDA). In topic modelling scenarios, the documents are often assumed to be in one, centralized dataset. However, sometimes documents are held by different parties, and contain privacy- or comm ..read more

ePrint Report: Some amortization techniques for FRI-based SNARKs Albert Garreta, Hayk Hovhanissyan, Aram Jivanyan, Ignacio Manzur, Isaac Villalobos, Michał Zając We present two techniques to improve the computational and/or communication costs of STARK proofs: packing and modular split-and-pack. Packing allows to generate a single proof of the satisfiability of several constraints. We achieve this by packing the evaluations of all relevant polynomials in the same Merkle leaves, and combining all DEEP FRI functions into a single randomized validity function. Our benchmarks show that packing red ..read more

ePrint Report: Agile, Post-quantum Secure Cryptography in Avionics Karolin Varner, Wanja Zaeske, Sven Friedrich, Aaron Kaiser, Alice Bowman To introduce a post-quantum-secure encryption scheme specifically for use in flight-computers, we used avionics’ module-isolation methods to wrap a recent encryption standard (HPKE – Hybrid Public Key Encryption) within a software partition. This solution proposes an upgrade to HPKE, using quantum-resistant ciphers (Kyber/ML-KEM and Dilithium/ML-DSA) redundantly alongside well-established ciphers, to achieve post-quantum security. Because cryptographic te ..read more

ePrint Report: Xproofs: New Aggregatable and Maintainable Matrix Commitment with Optimal Proof Size Xinwei Yong, Jiaojiao Wu, Jianfeng Wang Vector Commitment (VC) enables one to commit to a vector, and then the element at a specific position can be opened, with proof of consistency to the initial commitment. VC is a powerful primitive with various applications, including stateless cryptocurrencies. Recently, matrix commitment Matproofs (Liu and Zhang CCS 2022), as an extension of VC, has been proposed to reduce the communication and computation complexity of VC-based cryptocurrencies. However ..read more

ePrint Report: Pando: Extremely Scalable BFT Based on Committee Sampling Xin Wang, Haochen Wang, Haibin Zhang, Sisi Duan Byzantine fault-tolerant (BFT) protocols are known to suffer from the scalability issue. Indeed, their performance degrades drastically as the number of replicas $n$ grows. While a long line of work has attempted to achieve the scalability goal, these works can only scale to roughly a hundred replicas. In this paper, we develop BFT protocols from the so-called committee sampling approach that selects a small committee for consensus and conveys the results to all replicas. S ..read more

ePrint Report: Homomorphic Evaluation of LWR-based PRFs and Application to Transciphering Amit Deo, Marc Joye, Benoit Libert, Benjamin R. Curtis, Mayeul de Bellabre Certain applications such as FHE transciphering require randomness while operating over encrypted data. This randomness has to be obliviously generated in the encrypted domain and remain encrypted throughout the computation. Moreover, it should be guaranteed that independent-looking random coins can be obliviously generated for different computations. In this work, we consider the homomorphic evaluation of pseudorandom functions ..read more

ePrint Report: Private Analytics via Streaming, Sketching, and Silently Verifiable Proofs Mayank Rathee, Yuwen Zhang, Henry Corrigan-Gibbs, Raluca Ada Popa We present Whisper, a system for privacy-preserving collection of aggregate statistics. Like prior systems, a Whisper deployment consists of a small set of non-colluding servers; these servers compute aggregate statistics over data from a large number of users without learning the data of any individual user. Whisper’s main contribution is that its server- to-server communication cost and its server-side storage costs scale sublinearly with ..read more

ePrint Report: FE[r]Chain: Enforcing Fairness in Blockchain Data Exchanges Through Verifiable Functional Encryption Camille Nuoskala, Reyhaneh Rabbaninejad, Tassos Dimitriou, Antonis Michalas Functional Encryption (FE) allows users to extract specific function-related information from encrypted data while preserving the privacy of the underlying plaintext. Though significant research has been devoted to developing secure and efficient Multi-Input Functional Encryption schemes supporting diverse functions, there remains a noticeable research gap in the development of verifiable FE schemes. Func ..read more

ePrint Report: Faster Private Decision Tree Evaluation for Batched Input from Homomorphic Encryption Kelong Cong, Jiayi Kang, Georgio Nicolas, Jeongeun Park Privacy-preserving decision tree evaluation (PDTE) allows a client that holds feature vectors to perform inferences against a decision tree model on the server side without revealing feature vectors to the server. Our work focuses on the non-interactive batched setting where the client sends a batch of encrypted feature vectors and then obtains classifications, without any additional interaction. This is useful in privacy-preserving credit ..read more

Job Posting: Post-Doc Faculty of engineering, Bar-Ilan University, Israel A postdoctoral position is open in the faculty of engineering at Bar-Ilan University, hosted by Prof. Carmit Hazay and Prof. Ran Gelles. The position involves performing theoretical research in cryptography, particularly on secure computation over unreliable channels and networks where the adversary controls the communication channels. The position is offered for 1 year and can be extended by an additional year contingent upon funding and satisfactory performance. Applicants should ideally have a background in informa ..read more