Personne
Serge Vaudenay
Publications associées (237)
A Gapless Post-quantum Hash Proof System in the Hamming Metric
Serge Vaudenay, Bénédikt Minh Dang Tran
A hash proof system (HPS) is a form of implicit proof of membership to a language. Out of the very few existing post-quantum HPS, most are based on languages of ciphertexts of code-based or lattice-based cryptosystems and inherently suffer from a gap cause ...
2023Cryptographic Administration for Secure Group Messaging
Serge Vaudenay, Daniel Patrick Collins
Many real-world group messaging systems delegate group administration to the application level, failing to provide formal guarantees related to group membership. Taking a cryptographic approach to group administration can prevent both implementation and pr ...
2023Making Classical (Threshold) Signatures Post-quantum for Single Use on a Public Ledger
Serge Vaudenay, Laurane Chloé Angélina Marco, Abdullah Talayhan
The Bitcoin architecture heavily relies on the ECDSA signature scheme which is broken by quantum adversaries as the secret key can be computed from the public key in quantum polynomial time. To mitigate this attack, bitcoins can be paid to the hash of a pu ...
2023Extractable Witness Encryption for the Homogeneous Linear Equations Problem
Serge Vaudenay, Bénédikt Minh Dang Tran
Witness encryption is a cryptographic primitive which encrypts a message under an instance of an NP language and decrypts the ciphertext using a witness associated with that instance. In the current state of the art, most of the witness encryption construc ...
Springer2023Private Message Franking with After Opening Privacy
Serge Vaudenay, Iraklis Leontiadis
Recently Grubbs et al. [GLR17] initiated the formal study of message franking protocols. This new type of service launched by Facebook, allows the receiver in a secure messaging application to verifiably report to a third party an abusive message some send ...
2023Anonymous Tokens with Stronger Metadata Bit Hiding from Algebraic MACs
Serge Vaudenay, Fatma Betül Durak
On the one hand, the web needs to be secured from malicious activities such as bots or DoS attacks; on the other hand, such needs ideally should not justify services tracking people's activities on the web. Anonymous tokens provide a nice tradeoff between ...
2023Optimal Symmetric Ratcheting for Secure Communication
Serge Vaudenay, Andrea Felice Caforio, Daniel Patrick Collins, Hailun Yan
To mitigate state exposure threats to long-lived instant messaging sessions, ratcheting was introduced, which is used in practice in protocols like Signal. However, existing ratcheting protocols generally come with a high cost. Recently, Caforio et al. pro ...
OXFORD UNIV PRESS2022SwissCovid in the Perspective of Its Goals
Serge Vaudenay, Martin Vuagnoux
SwissCovid is the Swiss digital contact tracing app, which was deployed to help fighting against the COVID-19 pandemic. After a year of activity, it is high time to evaluate how effective it has been in its mission. At the highest peak, about 22% of the Sw ...
2022Towards Efficient LPN-Based Symmetric Encryption
Serge Vaudenay, Sonia Mihaela Bogos, Dario Korolija, Thomas Locher
Due to the rapidly growing number of devices that need to communicate securely, there is still significant interest in the development of efficient encryption schemes. It is important to maintain a portfolio of different constructions in order to enable a ...
Springer International Publishing2021Beyond Security and Efficiency: On-Demand Ratcheting with Security Awareness
Serge Vaudenay, Andrea Felice Caforio, Fatma Betül Durak
Secure asynchronous two-party communication applies ratcheting to strengthen privacy, in the presence of internal state exposures. Security with ratcheting is provided in two forms: forward security and post-compromise security. There have been several suc ...
2021