ePrint Report: Extending Groth16 for Disjunctive Statements Xudong Zhu, Xinxuan Zhang, Xuyang Song, Yi Deng, Yuanju Wei, Liuyu Yang Two most common ways to design non-interactive zero knowledge (NIZK) proofs are based on Sigma ($Sigma$)-protocols (an efficient way to prove algebraic statements) and zero-knowledge succinct non-interactive arguments of knowledge (zk-SNARK) protocols (an efficient way to…

ePrint Report: Chosen-Ciphertext Security for Inner Product FE: Mutli-Client and Multi-Input, Generically Ky Nguyen Functional Encryption is a powerful cryptographic primitive that allows for fine-grained access control over encrypted data. In the multi-user setting, especially Multi-Client and Multi-Input, a plethora of works have been proposed to study on concrete function classes, improving security, and more.…

ePrint Report: How to use your brain for cryptography without trustworthy machines Wakaha Ogata, Toi Tomita, Kenta Takahashi, Masakatsu Nishigaki In this work, we study cryptosystems that can be executed securely without fully trusting all machines, but only trusting the user’s brain. This paper focuses on signature scheme. We first introduce a new concept called…

ePrint Report: Constant time lattice reduction in dimension 4 with application to SQIsign Otto Hanyecz, Alexander Karenin, Elena Kirshanova, Péter Kutas, Sina Schaeffler In this paper we propose a constant time lattice reduction algorithm for integral dimension-4 lattices. Motivated by its application in the SQIsign post-quantum signature scheme, we provide for the first time a…

ePrint Report: Leveled Functional Bootstrapping via External Product Tree Zhihao Li, Xuan Shen, Xianhui Lu, Ruida Wang, Yuan Zhao, Zhiwei Wang, Benqiang Wei Multi-input and large-precision lookup table (LUT) evaluation pose significant challenges in Fully Homomorphic Encryption (FHE). Currently, two modes are employed to address this issue. One is tree-based functional bootstrapping (TFBS), which uses…

ePrint Report: Cryptography is Rocket Science: Analysis of BPSec Benjamin Dowling, Britta Hale, Xisen Tian, Bhagya Wimalasiri Space networking has become an increasing area of development with the advent of commercial satellite networks such as those hosted by Starlink and Kuiper, and increased satellite and space presence by governments around the world. Yet, historically such…

ePrint Report: Quantum-resistant secret handshakes with dynamic joining, leaving, and banishment: GCD revisited Olivier Blazy, Emmanuel Conchon, Philippe Gaborit, Philippe Krejci, Cristina Onete Secret handshakes, introduced by Balfanz et al. [3], allow users associated with various groups to determine if they share a common affiliation. These protocols ensure crucial properties such as fairness (all participants…

ePrint Report: Foundations of Platform-Assisted Auctions Hao Chung, Ke Wu, Elaine Shi Today, many auctions are carried out with the help of intermediary platforms like Google and eBay. These platforms serve as a rendezvous point for the buyers and sellers, and charge a fee for its service. We refer to such auctions as platform-assisted auctions.…

ePrint Report: ProbeShooter: A New Practical Approach for Probe Aiming Daehyeon Bae, Sujin Park, Minsig Choi, Young-Giu Jung, Changmin Jeong, Heeseok Kim, Seokhie Hong Electromagnetic side-channel analysis is a powerful method for monitoring processor activity and compromising cryptographic systems in air-gapped environments. As analytical methodologies and target devices evolve, the importance of leakage localization and…