Publications related to Digital signature

Side-channel analysis of isogeny-based key encapsulation mechanisms and hash-based digital signatures

Current cryptographic solutions will become obsolete with the arrival of large-scale universal quantum computers. As a result, the National Institute of Standards and Technology supervises a post-quantum standardization process which involves evaluating ca ...

EPFL2024

Exploring SIDH-Based Signature Parameters

Tako Boris Fouotsa, Laurane Chloé Angélina Marco, Andrea Basso

Isogeny-based cryptography is an instance of post-quantum cryptography whose fundamental problem consists of finding an isogeny between two (isogenous) elliptic curves E and E′. This problem is closely related to that of computing the endomorphism ring of ...

Springer2024

On the Theory and Practice of Modern Secure Messaging

Daniel Patrick Collins

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

Lattice-Based Blind Signatures: Short, Efficient, and Round-Optimal

Ngoc Khanh Karol Nguyen

We propose a 2-round blind signature protocol based on the random oracle heuristic and the hardness of standard lattice problems (Ring/Module-SIS/LWE and NTRU) with a signature size of 22 KB. The protocol is round-optimal and has a transcript size that can ...

Assoc Computing Machinery2023

Making Classical (Threshold) Signatures Post-quantum for Single Use on a Public Ledger

Serge Vaudenay, Laurane Chloé Angélina Marco, Abdullah Talayhan

The Bitcoin architecture heavily relies on the ECDSA signature scheme which is broken by quantum adversaries as the secret key can be computed from the public key in quantum polynomial time. To mitigate this attack, bitcoins can be paid to the hash of a pu ...

2023

Global, Passive Detection of Connection Tampering

Louis-Henri Manuel Jakob Merino

In-network devices around the world monitor and tamper with connections for many reasons, including intrusion prevention, combating spam or phishing, and country-level censorship. Connection tampering seeks to block access to specific domain names or keywo ...

Assoc Computing Machinery2023

Reliable Microsecond-Scale Distributed Computing

Athanasios Xygkis

The landscape of computing is changing, thanks to the advent of modern networking equipment that allows machines to exchange information in as little as one microsecond. Such advancement has enabled microsecond-scale distributed computing, where entire dis ...

EPFL2023

New SIDH Countermeasures for a More Efficient Key Exchange

Tako Boris Fouotsa, Andrea Basso

The Supersingular Isogeny Diffie-Hellman (SIDH) protocol has been the main and most efficient isogeny-based encryption protocol, until a series of breakthroughs led to a polynomial-time key-recovery attack. While some countermeasures have been proposed, th ...

Springer2023

BLOOM: Bimodal Lattice One-out-of-Many Proofs and Applications

Ngoc Khanh Karol Nguyen

We give a construction of an efficient one-out-of-many proof system, in which a prover shows that he knows the pre-image for one element in a set, based on the hardness of lattice problems. The construction employs the recent zero-knowledge framework of Ly ...

SPRINGER INTERNATIONAL PUBLISHING AG2022

Oracular Byzantine Reliable Broadcast

Rachid Guerraoui, Martina Camaioni, Matteo Monti, Manuel José Ribeiro Vidigueira

Byzantine Reliable Broadcast (BRB) is a fundamental distributed computing primitive, with applications ranging from notifications to asynchronous payment systems. Motivated by practical consideration, we study Client-Server Byzantine Reliable Broadcast (CS ...

Schloss Dagstuhl - Leibniz-Zentrum für Informatik2022

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

On the Effectiveness of Time Travel to Inject COVID-19 Alerts

Serge Vaudenay, Martin Vuagnoux

Digital contact tracing apps allow to alert people who have been in contact with people who may be contagious. The Google/Apple Exposure Notification (GAEN) system is based on Bluetooth proximity estimation. It has been adopted by many countries around the ...

Springer, Cham2021

The Performance of Byzantine Fault Tolerant Blockchains

Vincent Gramoli

Blockchains have captured the attention of many, resulting in an abundance of new systems available for use. However, selecting an appropriate blockchain for an application is challenging due to the lack of comparative information discussing core metrics s ...

IEEE2020

Are Cloud FPGAs Really Vulnerable to Power Analysis Attacks?

Francesco Regazzoni, Mirjana Stojilovic, Ognjen Glamocanin, Louis Coulon

Recent works have demonstrated the possibility of extracting secrets from a cryptographic core running on an FPGA by means of remote power analysis attacks. To mount these attacks, an adversary implements a voltage fluctuation sensor in the FPGA logic, rec ...

IEEE2020

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

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

Cryptanalysis of ForkAES

Subhadeep Banik, Willi Meier

Forkciphers are a new kind of primitive proposed recently by Andreeva et al. for efficient encryption and authentication of small messages. They fork the middle state of a cipher and encrypt it twice under two smaller independent permutations. Thus, forkci ...

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

Misuse Attacks on Post-quantum Cryptosystems

Serge Vaudenay, Loïs Evan Huguenin-Dumittan, Abdullah Talayhan, Fatma Betül Durak, Ciprian Baetu

Many post-quantum cryptosystems which have been proposed in the National Institute of Standards and Technology (NISI) standardization process follow the same meta-algorithm, but in different algebras or different encoding methods. They usually propose two ...

SPRINGER INTERNATIONAL PUBLISHING AG2019