ePrint Report: Preprocessing Security in Multiple Idealized Models with Applications to Schnorr Signatures and PSEC-KEM Jeremiah Blocki, Seunghoon Lee In modern cryptography, relatively few instantiations of foundational cryptographic primitives are used across most cryptographic protocols. For example, elliptic curve groups are typically instantiated using P-256, P-384, Curve25519, or Curve448, while block ciphers are commonly instantiated…

ePrint Report: FINAL bootstrap acceleration on FPGA using DSP-free constant-multiplier NTTs Jonas Bertels, Hilder V. L. Pereira, Ingrid Verbauwhede This work showcases Quatorze-bis, a state-of-the-art Number Theoretic Transform circuit for TFHE-like cryptosystems on FPGAs. It contains a novel modular multiplication design for modular multiplication with a constant for a constant modulus. This modular multiplication design…

ePrint Report: Isogeny-based Cryptography using Isomorphisms of Superspecial Abelian Surfaces Pierrick Gaudry, Julien Soumier, Pierre-Jean Spaenlehauer We investigate the algorithmic problem of computing isomorphisms between products of supersingular elliptic curves, given their endomorphism rings. This computational problem seems to be difficult when the domain and codomain are fixed, whereas we provide efficient algorithms to compute…

ePrint Report: PRISM: Simple And Compact Identification and Signatures From Large Prime Degree Isogenies Andrea Basso, Giacomo Borin, Wouter Castryck, Maria Corte-Real Santos, Riccardo Invernizzi, Antonin Leroux, Luciano Maino, Frederik Vercauteren, Benjamin Wesolowski The problem of computing an isogeny of large prime degree from a supersingular elliptic curve of unknown endomorphism ring is assumed to…

ePrint Report: TockOwl: Asynchronous Consensus with Fault and Network Adaptability Minghang Li, Qianhong Wu, Zhipeng Wang, Bo Qin, Bohang Wei, Hang Ruan, Shihong Xiong, Zhenyang Ding BFT protocols usually have a waterfall-like degradation in performance in the face of crash faults. Some BFT protocols may not experience sudden performance degradation under crash faults. They achieve…

ePrint Report: Distributional Private Information Retrieval Ryan Lehmkuhl, Alexandra Henzinger, Henry Corrigan-Gibbs A private-information-retrieval (PIR) scheme lets a client fetch a record from a remote database without revealing which record it fetched. Classic PIR schemes treat all database records the same but, in practice, some database records are much more popular (i.e., commonly fetched) than…

ePrint Report: Cryptanalysis of an Efficient Signature Based on Isotropic Quadratic Forms Henry Bambury, Phong Q. Nguyen We present a key-recovery attack on DEFI, an efficient signature scheme proposed recently by Feussner and Semaev, and based on isotropic quadratic forms, borrowing from both multivariate and lattice cryptography. Our lattice-based attack is partially heuristic, but works…

ePrint Report: On the Anonymity of Linkable Ring Signatures Xavier Bultel, Charles Olivier-Anclin Security models provide a way of formalising security properties in a rigorous way, but it is sometimes difficult to ensure that the model really fits the concept that we are trying to formalise. In this paper, we illustrate this fact by showing…

ePrint Report: Symmetric Perceptrons, Number Partitioning and Lattices Neekon Vafa, Vinod Vaikuntanathan The symmetric binary perceptron ($mathrm{SBP}_{kappa}$) problem with parameter $kappa : mathbb{R}_{geq1} to [0,1]$ is an average-case search problem defined as follows: given a random Gaussian matrix $mathbf{A} sim mathcal{N}(0,1)^{n times m}$ as input where $m geq n$, output a vector $mathbf{x} in {-1,1}^m$…

ePrint Report: DewTwo: a transparent PCS with quasi-linear prover, logarithmic verifier and 4.5KB proofs from falsifiable assumptions Benedikt Bünz, Tushar Mopuri, Alireza Shirzad, Sriram Sridhar We construct the first polynomial commitment scheme (PCS) that has a transparent setup, quasi-linear prover time, $log N$ verifier time, and $log log N$ proof size, for multilinear polynomials of…