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…

ePrint Report: Efficient Authentication Protocols from the Restricted Syndrome Decoding Problem Thomas Johansson, Mustafa Khairallah, Vu Nguyen In this paper, we introduce an oracle version of the Restricted Syndrome Decoding Problem (RSDP) and propose novel authentication protocols based on the hardness of this problem. They follow the basic structure of the HB-family of authentication protocols…

Event Calendar: The 20th International Workshop on Security (IWSEC 2025) (1st round submission) Fukuoka, Japan, 25 November – 27 November 2025 Event date: 25 November to 27 November 2025 Submission deadline: 3 April 2025 Notification: 2 June 2025 Go to Source

ePrint Report: On the Independence Assumption in Quasi-Cyclic Code-Based Cryptography Maxime Bombar, Nicolas Resch, Emiel Wiedijk Cryptography based on the presumed hardness of decoding codes — i.e., code-based cryptography — has recently seen increased interest due to its plausible security against quantum attackers. Notably, of the four proposals for the NIST post-quantum standardization process that…