Research Papers

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.

In this work, which was accepted at USENIX Security 2025, we propose a new way of modeling Signal handshake protocols.

More Efficient Protocols for Post-Quantum Secure Messaging is a talk presented by Thomas Prest at RWC 2024. This was the third talk in a session on post-quantum messaging, chaired by Dan Boneh.

We present the first comprehensive study on thresholdizing practical OV-based signature schemes, specifically focusing on MAYO and UOV.

In this article we present a non-uniform reduction from rank-2 module-LIP over Complex Multiplication fields, to a variant of the Principal Ideal Problem, in some fitting quaternion algebra.

In this work, we generalize the attack of Mureau et al. against rank-2module-LIP to the family of all number fields with at least one real embedding, which contains the NTRU Prime fields.

Due to the imminent threat of a "Harvest Now, Decrypt Later" attack, secure messaging providers must react know in order to make their protocols : at least as secure as before, but now also post-quantum (PQ) secure.

We propose a novel very efficient threshold signature scheme, with a signature size close to that of a single Dilithium signature for any threshold T of at most 8 users.

We propose a recursive lattice reduction framework for finding short non-zero vectors or dense sublattices of a lattice.

In this work, we formally prove a tight security bound for SPHINCS+ using the EasyCrypt proof assistant, establishing greater confidence in the general security of the scheme and that of the parameter sets considered for standardization.

We construct an efficient dynamic group signature (or more generally an accountable ring signature) from isogeny and lattice assumptions.