Publications associées à Ciphertext-only attack

Analyzing and Protecting Communication Metadata

Most communication systems (e.g., e-mails, instant messengers, VPNs) use encryption to prevent third parties from learning sensitive information. However, encrypted communications protect the contents but often leak metadata: the amount of data sent and th ...

EPFL2021

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

Can Caesar Beat Galois?

Serge Vaudenay, Damian Vizár

The Competition for Authenticated Encryption: Security, Applicability and Robustness (CAESAR) has as its official goal to “identify a portfolio of authenticated ciphers that offer advantages over [the Galois-Counter Mode with AES]” and are suitable for wid ...

2018

The Hidden Vulnerability of Distributed Learning in Byzantium

Rachid Guerraoui, El Mahdi El Mhamdi, Sébastien Louis Alexandre Rouault

While machine learning is going through an era of celebrated success, concerns have been raised about the vulnerability of its backbone: stochastic gradient descent (SGD). Recent approaches have been proposed to ensure the robustness of distributed SGD aga ...

2018

Breaking The FF3 Format-Preserving Encryption Standard Over Small Domains

Serge Vaudenay, Fatma Betül Durak

The National Institute of Standards and Technology (NIST) recently published a Format-Preserving Encryption standard accepting two Feistel structure based schemes called FF1 and FF3. Particularly, FF3 is a tweakable block cipher based on an 8-round Feistel ...

2017

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

On Selection of Samples in Algebraic Attacks and a New Technique to Find Hidden Low Degree Equations

Serge Vaudenay, Pouyan Sepehrdad, Petr Susil

The best way of selecting samples in algebraic attacks against block ciphers is not well explored and understood. We introduce a simple strategy for selecting the plaintexts and demonstrate its strength by breaking reduced-round KATAN, LBLOCK and SIMON. Fo ...

Springer Verlag2016

Protecting against Multidimensional Linear and Truncated Differential Cryptanalysis by Decorrelation

Serge Vaudenay

The decorrelation theory provides a different point of view on the security of block cipher primitives. Results on some statistical attacks obtained in this context can support or provide new insight on the security of symmetric cryptographic primitives. I ...

Springer-Verlag Berlin2015

On Selection of Samples in Algebraic Attacks and a New Technique to Find Hidden Low Degree Equations

Serge Vaudenay, Pouyan Sepehrdad, Petr Susil

The best way of selecting samples in algebraic attacks against block ciphers is not well explored and understood. We introduce a simple strategy for selecting the plaintexts and demonstrate its strength by breaking reduced-round KATAN32 and LBlock. In both ...

Springer-Verlag Berlin2014

Unifying Leakage Models: From Probing Attacks to Noisy Leakage

Alexandre Raphaël Duc, Sebastian Faust

A recent trend in cryptography is to formally show the leakage resilience of cryptographic implementations in a given leakage model. One of the most prominent leakage models -- the so-called bounded leakage model -- assumes that the amount of leakage is a- ...

Springer2014