Publications related to Secure channel

On the Theory and Practice of Modern Secure Messaging

Billions of people now have conversations daily over the Internet. A large portion of this communication takes place via secure messaging protocols that offer "end-to-end encryption'" guarantees and resilience to compromise like the widely-used Double Ratc ...

EPFL2024

Beyond Security and Efficiency: On-Demand Ratcheting with Security Awareness

Serge Vaudenay, Fatma Betül Durak, Andrea Felice Caforio

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

CALYPSO: Private Data Management for Decentralized Ledgers

Bryan Alexander Ford, Linus Gasser, Eleftherios Kokoris Kogias, Philipp Svetolik Jovanovic, Enis Ceyhun Alp

Distributed ledgers provide high availability and integrity, making them a key enabler for practical and secure computation of distributed workloads among mutually distrustful parties. Many practical applications also require strong confidentiality, howeve ...

2021

Towards 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 Publishing AG2021

Secrecy by Design With Applications to Privacy and Compression

Yanina Yurina Shkel

Secrecy by design is examined as an approach to information-theoretic secrecy. The main idea behind this approach is to design an information processing system from the ground up to be perfectly secure with respect to an explicit secrecy constraint. The pr ...

2021

Symmetric Asynchronous Ratcheted Communication with Associated Data

Serge Vaudenay, Hailun Yan

Following up mass surveillance and privacy issues, modern secure communication protocols now seek strong security, such as forward secrecy and post-compromise security, in the face of state exposures. To address this problem, ratcheting was thereby introdu ...

Springer, Cham2020

Methods and systems for secure data exchange

Bryan Alexander Ford, Linus Gasser, Eleftherios Kokoris Kogias

The present invention concerns a computer-implemented method for secure data exchange between a sender (A) and a recipient (B), wherein the method is performed by the sender (A) and comprises encrypting data using a symmetric key k, creating a write transa ...

2019

On the Security of Two-Round Multi-Signatures

Bryan Alexander Ford, Manu Drijvers, Kasra Edalatnejadkhamene

A multi-signature scheme allows a group of signers to collaboratively sign a message, creating a single signature that convinces a verifier that every individual signer approved the message. The increased interest in technologies to decentralize trust has ...

IEEE Computer Society2019

Bidirectional Asynchronous Ratcheted Key Agreement with Linear Complexity

Serge Vaudenay, Fatma Betül Durak

Following up mass surveillance and privacy issues, modern secure communication protocols now seek more security such as forward secrecy and post-compromise security. They cannot rely on an assumption such as synchronization, predictable sender/receiver rol ...

Springer2019

SUNDAE: Small Universal Deterministic Authenticated Encryption for the Internet of Things

Subhadeep Banik

Lightweight cryptography was developed in response to the increasing need to secure devices for the Internet of Things. After significant research effort, many new block ciphers have been designed targeting lightweight settings, optimizing efficiency metri ...

2018

Provably Secure Authenticated Encryption

Damian Vizár

Authenticated Encryption (AE) is a symmetric key cryptographic primitive that ensures confidentiality and authenticity of processed messages at the same time. The research of AE as a primitive in its own right started in 2000. The security goals of AE wer ...

EPFL2018

LPN in Cryptography : an Algorithmic Study

Sonia Mihaela Bogos

The security of public-key cryptography relies on well-studied hard problems, problems for which we do not have efficient algorithms. Factorization and discrete logarithm are the two most known and used hard problems. Unfortunately, they can be easily solv ...

EPFL2017

PriFi: A Low-Latency and Tracking-Resistant Protocol for Local-Area Anonymous Communication

Jean-Pierre Hubaux, Ludovic Barman, Bryan Alexander Ford, Mahdi Zamani, Italo Ivan Dacosta Petrocelli

Popular anonymity mechanisms such as Tor provide low communication latency but are vulnerable to traffic analysis attacks that can de-anonymize users. Moreover, known traffic-analysis-resistant techniques such as Dissent are impractical for use in latency- ...

ACM2016

Practical and Provably Secure Distance-Bounding

Serge Vaudenay, Aikaterini Mitrokotsa

From contactless payments to remote car unlocking, many applications are vulnerable to relay attacks. Distance bounding protocols are the main practical countermeasure against these attacks. In this paper, we present a formal analysis of SKI, which recentl ...

IOS Press2015

Secure Wireless Communications via Cooperative Transmitting

Ninoslav Marina

Information-theoretic secrecy is combined with cryptographic secrecy to create a secret-key exchange protocol for wireless networks. A network of transmitters, which already have cryptographically secured channels between them, cooperate to exchange a secr ...

Hindawi Publishing Corporation2014

Bounded Tamper Resilience: How to go beyond the Algebraic Barrier

Sebastian Faust

Related key attacks (RKAs) are powerful cryptanalytic attacks where an adversary can change the secret key and observe the effect of such changes at the output. The state of the art in RKA security protects against an a-priori unbounded number of certain a ...

2013

Practical & Provably Secure Distance-Bounding

Serge Vaudenay, Aikaterini Mitrokotsa

From contactless payments to remote car unlocking, many applications are vulnerable to relay attacks. Distance bounding protocols are the main practical countermeasure against these attacks. At FSE 2013, we presented SKI as the first family of provably sec ...

2013

OREN: Optimal Revocations in Ephemeral Networks

Jean-Pierre Hubaux, Maxime Raya, Igor Bilogrevic

Public-key certificates allow a multitude of entities to securely exchange and verify the authenticity of data. However, the ability to effectively revoke compromised or untrustworthy certificates is of great importance when coping with misbehavior. In thi ...

2011

Broadcast Encryption and Traitor Tracing for Conditional Access Systems

Alexandre Karlov

In the context of the thesis we are studying the notions of broadcast encryption and traitor tracing in an industrial framework of conditional access systems related to Pay-TV. Broadcast encryption represents a cryptographic primitive which allows confiden ...

EPFL2011

Cryptographic Hash Functions in Groups and Provable Properties

Juraj Sarinay

We consider several "provably secure" hash functions that compute simple sums in a well chosen group (G,*). Security properties of such functions provably translate in a natural way to computational problems in G that are simple to define and possibly also ...

EPFL2011