Research Papers

To securepost-quantum transition, this paper introduces Hybrid EU-CMA and Silithium. By combining classical and PQ algorithms, Silithium prevents separability attacks while offering faster speeds and smaller sizes than simple concatenation.

Falcon is a post-quantum signature scheme that usually relies on inefficient trial-and-error. This new MCMC sampling method achieves higher security and shorter signatures more efficiently while simplifying the system's overall implementation.

Today marks a massive milestone for Japan’s digital sovereignty. Following PQShield’s comprehensive evaluation of the ML-KEM algorithm for CRYPTREC (Japan’s cryptographic standardization body), the gates are officially open for quantum-safe deployment across the country’s government procurement and technology supply chains.

This is paper is concerned with the theoretical basis of lattice-based cryptography, clarifying how “easy” distinguishing attacks relate to “hard” search attacks used in security proofs.

In this paper, we present a simpler, more efficient way to create a secure, quantum-resistant shared "vault" (a threshold KEM) without using overly complex or slow mathematical tools. It's achieved by combining established cryptographic frameworks with a new, proven mathematical assumption called Coset-Hint-MLWE. The result is a highly secure system that is easier to implement and more practical for real-world use than previous versions.

Recent efforts to transition secure messaging to post-quantum standards, like Apple’s PQ3 and Signal’s updated Triple Ratchet, have introduced complex design trade-offs due to the high communication overhead of post-quantum cryptography. This paper introduces a pragmatic metric and experimental framework to compare these protocols, revealing that no "optimal" protocol exists when balancing security against real-world bandwidth constraints. Additionally, the authors propose a new optimization called "opportunistic sending" and a building block termed "sparse continuous key agreement" to improve protocol efficiency.

We propose a hybrid formal verification approach that combines high-level deductive reasoning and circuit-based reasoning and apply it to highly optimized cryptographic assembly code.

Continuous Group Key Agreement (CGKA) is the primitive underlying secure group messaging. It allows a large group of N users to maintain a shared secret key that is frequently rotated by the group members in order to achieve forward secrecy and post compromise security.

In this work, we propose TRaccoon-IA, a TRaccoon with an efficient identifiable abort protocol, allowing to identify malicious signers when the signing protocol fails.

We analyze Signal's classically secure X3DH and harvest-now-decrypt-later-secure PQXDH, and show the settings for which PQXDH is (un)deniable against harvest-now--later attacks..and more.

In this work, we focus on the authenticity of the application messages exchanged in MLS.