Publications associées à Non-répudiation

Extractable Witness Encryption for the Homogeneous Linear Equations Problem

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 ...

Springer2023

Privacy and Integrity Preserving Computations with CRISP

Jean-Pierre Hubaux, Juan Ramón Troncoso-Pastoriza, Apostolos Pyrgelis, Sylvain Chatel

In the digital era, users share their personal data with service providers to obtain some utility, e.g., access to high-quality services. Yet, the induced information flows raise privacy and integrity concerns. Consequently, cautious users may want to prot ...

USENIX ASSOC2021

Time in cryptography

Gwangbae Choi

Time travel has always been a fascinating topic in literature and physics. In cryptography, one may wonder how to keep data confidential for some time. In this dissertation, we will study how to make private information travel to the future. This dissertat ...

EPFL2020

ClaimChain: Improving the Security and Privacy of In-band Key Distribution for Messaging

Carmela González Troncoso, Wouter Lueks, Bogdan Kulynych

The social demand for email end-to-end encryption is barely supported by mainstream service providers. Autocrypt is a new community -driven open specification for e-mail encryption that attempts to respond to this demand. In Autocrypt the encryption keys a ...

ACM2018

Misuse-Resistant Variants of the OMD Authenticated Encryption Mode

Serge Vaudenay, Damian Vizár, Reza Reyhanitabar

We present two variants of OMD which are robust against nonce misuse. Security of OMD---a CAESAR candidate---relies on the assumption that implementations always ensure correct use of nonce (a.k.a. message number); namely that, the nonce never gets repeate ...

Springer-Verlag Berlin2014

Forgery-Resilience for Digital Signature Schemes

Khaled Ouafi, Atefeh Mashatan

We introduce the notion of forgery-resilience for digital signature schemes, a new paradigm for digital signature schemes exhibiting desirable legislative properties. It evolves around the idea that, for any message, there can only be a unique valid signat ...

2012

Efficient Fail-Stop Signatures from the Factoring Assumption

Khaled Ouafi, Atefeh Mashatan

In this paper, we revisit the construction of fail-stop signatures from the factoring assumption. These signatures were originally proposed to provide information-theoretic-based security against forgeries. In contrast to classical signature schemes, in wh ...

Springer2011

Short Undeniable Signatures Based on Group Homomorphisms

Serge Vaudenay, Jean Monnerat

This paper is devoted to the design and analysis of short undeniable signatures based on a random oracle. Exploiting their online property, we can achieve signatures with a fully scalable size depending on the security level. To this end, we develop a gene ...

Springer Verlag2011

(In)Security of an Efficient Fingerprinting Scheme with Symmetric and Commutative Encryption of IWDW 2005

We analyze the security of a fingerprinting scheme proposed at IWDW 2005. We show two results, namely that this scheme (1) does not provide seller security: a dishonest buyer can repudiate the fact that he redistributed a content, and (2) does not provide ...

Springer2008

SAS-Based Group Authentication and Key Agreement Protocols

Sylvain Pasini

New trends in consumer electronics have created a strong demand for fast, reliable and user-friendly key agreement protocols. However, many key agreement protocols are secure only against passive attacks. Therefore, message authentication is often unavoida ...

Springer2008