Concept

Semantic security

Related publications (22)

Secure and Efficient Cryptographic Algorithms in a Quantum World

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

Cryptanalysis of LowMC instances using single plaintext/ciphertext pair

Serge Vaudenay, Subhadeep Banik, Fatma Betül Durak, Khashayar Barooti

Arguably one of the main applications of the LowMC family ciphers is in the post-quantum signature scheme PICNIC. Although LowMC family ciphers have been studied from a cryptanalytic point of view before, none of these studies were directly concerned with ...

2020

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

Improving Stateless Hash-Based Signatures

Jean-Philippe Aumasson

present several optimizations to SPHINCS, a stateless hash-based signature scheme proposed by Bernstein et al. in (2015): PORS, a more secure variant of the HORS few-time signature scheme used in SPHINCS; secret key caching, to speed-up signing and reduce ...

SPRINGER INTERNATIONAL PUBLISHING AG2018

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

Implications of Position in Cryptography

Handan Kilinç Alper

In our daily lives, people or devices frequently need to learn their location for many reasons as some services depend on the absolute location or the proximity. The outcomes of positioning systems can have critical effects e.g., on military, emergency. Th ...

EPFL2018

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

Optimal Proximity Proofs

Serge Vaudenay

Provably secure distance-bounding is a rising subject, yet an unsettled one; indeed, very few distance-bounding protocols, with formal security proofs, have been proposed. In fact, so far only two protocols, namely SKI (by Boureanu et al.) and FO (by Fisch ...

Springer2015

Algebraic Cryptanalysis of Deterministic Symmetric Encryption

Petr Susil

Deterministic symmetric encryption is widely used in many cryptographic applications. The security of deterministic block and stream ciphers is evaluated using cryptanalysis. Cryptanalysis is divided into two main categories: statistical cryptanalysis and ...

EPFL2015

HELEN: A Public-Key Cryptosystem Based on the LPN and the Decisional Minimal Distance Problems

Serge Vaudenay, Alexandre Raphaël Duc

We propose HELEN, a code-based public-key cryptosystem whose security is based on the hardness of the Learning from Parity with Noise problem (LPN) and the decisional minimum distance problem. We show that the resulting cryptosystem achieves indistinguisha ...

Springer2013

Securing Broadcast Against Dishonest Receivers

Christina Fragouli, Suhas Diggavi, László Czap, Vinod Malathidevi Prabhakaran

Consider a sender, Alice, who wants to transmit private messages to two receivers, Bob and Calvin, using unreliable wireless broadcast transmissions and short public feedback from Bob and Calvin. In [1], we assumed that Bob and Calvin provide honest feedba ...

IEEE2013

Asynchronous Gossip

Rachid Guerraoui, Seth Gilbert

We study the complexity of gossip in an asynchronous, message-passing fault-prone distributed system. We show that an adaptive adversary can significantly hamper the spreading of a rumor, while an oblivious adversary cannot. The algorithmic techniques prop ...

Association for Computing Machinery2013

Primeless Factoring-Based Cryptography

Serge Vaudenay, Sonia Mihaela Bogos, Ioana Cristina Carlson

Factoring-based public-key cryptosystems have an overall complexity which is dominated by the key-production algorithm, which requires the generation of prime numbers. This is most inconvenient in settings where the key-generation is not an one-off process ...

2013

HELEN: a Public-key Cryptosystem Based on the LPN Problem (Extended Abstract)

Serge Vaudenay, Alexandre Raphaël Duc

We propose HELEN, a new code-based public-key cryptosystem whose security is based on the hardness of the Learning from Parity with Noise problem~(LPN) and the decisional minimum distance problem. We show that the resulting cryptosystem achieves indistingu ...

2012

Primeless Modular Cryptography (Extended Abstract)

Serge Vaudenay, Sonia Mihaela Bogos, Ioana Cristina Carlson

Most of the known public-key cryptosystems have an overall complexity which is dominated by the key-production algorithm, which requires the generation of prime numbers. This is most inconvenient in settings where the key-generation is not an one-off proce ...

2012

How to Allocate Tasks Asynchronously

Rachid Guerraoui, Seth Gilbert, Dan Alistarh

Asynchronous task allocation is a fundamental problem in distributed computing in which p asynchronous processes must execute a set of m tasks. Also known as write-all or do-all, this problem been studied extensively, both independently and as a key buildi ...

IEEE2012

On Hiding a Plaintext Length by Preencryption

Serge Vaudenay, Cihangir Tezcan

It is a well known fact that encryption schemes can not hide a plaintext length when it is unbounded. We thus admit that an approximation of it may leak and we focus on hiding its precise value. Some standards such as TLS or SSH offer to do it by applying ...

Springer2011

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

Enabling Secure Secret Sharing in Distributed Online Social Networks

Karl Aberer, Anwitaman Datta, Sonja Buchegger

We study a new application of threshold-based secret sharing in a distributed online social network (DOSN), where users need a means to back up and recover their private keys in a network of untrusted servers. Using a simple threshold-based secret sharing ...

Ieee Computer Soc Press, Customer Service Center, Po Box 3014, 10662 Los Vaqueros Circle, Los Alamitos, Ca 90720-1264 Usa2009

On the Complexity of Asynchronous Gossip

Rachid Guerraoui, Seth Gilbert

In this paper, we study the complexity of gossip in an asynchronous, message-passing fault-prone distributed system. In short, we show that an adaptive adversary can significantly hamper the spreading of a rumor, while an oblivious adversary cannot. In the ...

2008