Publications associées à Pretty Good Privacy

Rapidly verifiable aggregate signatures

Rachid Guerraoui, Gauthier Jérôme Timothée Voron, Martina Camaioni, Matteo Monti, Manuel José Ribeiro Vidigueira, Pierre-Louis Blaise Roman

A method for aggregating digital signatures comprises the following steps carried out by a signature aggregator: receiving first data packages from signers, each first data package comprising a signer identifier, a payload, and a payload signature; verifyi ...

2024

Secure and Efficient Cryptographic Algorithms in a Quantum World

Loïs Evan Huguenin-Dumittan

Since the advent of internet and mass communication, two public-key cryptographic algorithms have shared the monopoly of data encryption and authentication: Diffie-Hellman and RSA. However, in the last few years, progress made in quantum physics -- and mo ...

EPFL2024

Authenticated private information retrieval

Bryan Alexander Ford, Simone Maria Stefano Colombo, Henry Nathaniel Corrigan-Gibbs, Kirill Nikitin

This paper introduces protocols for authenticated private information retrieval. These schemes enable a client to fetch a record from a remote database server such that (a) the server does not learn which record the client reads, and (b) the client either ...

Usenix Assoc2023

Attestable Software Versioning for Stateful Confidential Computing

Edouard Bugnion, Charly Nicolas Lucien Castes

Trusted execution environments enable the creation of confidential and attestable enclaves that exclude the platform and service providers from the trusted base. From its initial attestable state, a stateful enclave such as a confidential database can hold ...

2022

Optimal 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 PRESS2022

Integrity and Metadata Protection in Data Retrieval

Kirill Nikitin

Secure retrieval of data requires integrity, confidentially, transparency, and metadata-privacy of the process. Existing protection mechanisms, however, provide only partially these properties: encryption schemes still expose cleartext metadata, protocols ...

EPFL2021

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

Timed-Release Encryption With Master Time Bound Key

Serge Vaudenay, Gwangbae Choi

Timed-release encryption allows senders to send a message to a receiver which cannot decrypt until a server releases a time bound key at the release time. The release time usually supposed to be known to the receiver, the ciphertext therefore cannot be dec ...

2019

Six Shades of AES

Subhadeep Banik, Muhammed Fatih Balli

Recently there have been various attempts to construct light weight implementations of the AES-128 encryption and combined encryption/ decryption circuits. However no known lightweight circuit exists forAES-192 and AES-256, the variants of AES that use lon ...

2019

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

Experimental Comparison of Multicast Authentication for Wide Area Monitoring Systems

Jean-Yves Le Boudec, Teklemariam Tsegay Tesfay

Multicast is proposed as a preferred communication mechanism for many power grid applications. One of the biggest challenges for multicast in smart grid is ensuring source authentication without violating the stringent time requirement. The research commun ...

2017

Privacy-Friendly Photo Sharing and Relevant Applications Beyond

Lin Yuan

Popularization of online photo sharing brings people great convenience, but has also raised concerns for privacy. Researchers proposed various approaches to enable image privacy, most of which focus on encrypting or distorting image visual content. In this ...

EPFL2017

Breaking the FF3 Format Preserving Encryption

Serge Vaudenay, Fatma Betül Durak

The NIST standard FF3 scheme (also known as BPS scheme) is a tweakable block cipher based on a 8-round Feistel Network. We break it with a practical attack. Our attack exploits the bad domain separation in FF3 design. The attack works with chosen plaintext ...

2017

Building Privacy-Preserving Cryptographic Credentials from Federated Online Identities

Bryan Alexander Ford, Ennan Zhai

Federated identity providers, e.g., Facebook and PayPal, offer a convenient means for authenticating users to third-party applications. Unfortunately such cross-site authentications carry privacy and tracking risks. For example, federated identity provider ...

Association for Computing Machinery2016

Authenticated Encryption with Variable Stretch

Serge Vaudenay, Damian Vizár, Reza Reyhanitabar

In conventional authenticated-encryption (AE) schemes, the ciphertext expansion, a.k.a.stretch or tag length, is a constant or a parameter of the scheme that must be fixed per key. However, using variable-length tags per key can be desirable in practice or ...

Springer-Verlag Berlin2016

GenoGuard: Protecting Genomic Data against Brute-Force Attacks

Jean-Pierre Hubaux, Jacques Fellay, Erman Ayday, Zhicong Huang, Ari Juels

Secure storage of genomic data is of great and increasing importance. The scientific community's improving ability to interpret individuals' genetic materials and the growing size of genetic database populations have been aggravating the potential conseque ...

2015

Privacy-Preserving Photo Sharing based on a Public Key Infrastructure

Touradj Ebrahimi, Lin Yuan, David Mc Nally

A significant number of pictures are posted to social media sites or exchanged through instant messaging and cloud-based sharing services. Most social media services offer a range of access control mechanisms to protect users privacy. As it is not in the b ...

Spie-Int Soc Optical Engineering2015

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

User-side adaptive protection of location privacy in participatory sensing

Karl Aberer, Jean-Pierre Hubaux, Rammohan Narendula, Berker Agir

The participatory sensing paradigm, through the growing availability of cheap sensors in mobile devices, enables applications of great social and business interest, e.g., electrosmog exposure measurement and early earthquake detection. However, users' priv ...

Springer Verlag2014

On the Cryptanalysis of Public-Key Cryptography

Joppe Willem Bos

Nowadays, the most popular public-key cryptosystems are based on either the integer factorization or the discrete logarithm problem. The feasibility of solving these mathematical problems in practice is studied and techniques are presented to speed-up the ...

EPFL2012