Publications related to Adversary (cryptography)

Bayes Security: A Not So Average Metric

Carmela González Troncoso, Giovanni Cherubin

Security system designers favor worst-case security metrics, such as those derived from differential privacy (DP), due to the strong guarantees they provide. On the downside, these guarantees result in a high penalty on the system's performance. In this pa ...

IEEE2023

Thwarting Malicious Adversaries in Homomorphic Encryption Pipelines

Sylvain Chatel

Homomorphic Encryption (HE) enables computations to be executed directly on encrypted data. As such, it is an auspicious solution for protecting the confidentiality of sensitive data without impeding its usability. However, HE does not provide any guarant ...

EPFL2023

Analysis and Improvements of the Sender Keys Protocol for Group Messaging

Daniel Patrick Collins

Messaging between two parties and in the group setting has enjoyed widespread attention both in practice, and, more recently, from the cryptographic community. One of the main challenges in the area is constructing secure (end-to- end encrypted) and effici ...

2022

Six shades lighter: a bit-serial implementation of the AES family

Subhadeep Banik, Muhammed Fatih Balli, Sergio Roldán Lombardía

Recently, cryptographic literature has seen new block cipher designs such as PRESENT, GIFT or SKINNY that aim to be more lightweight than the current standard, i.e., AES. Even though AES family of block ciphers were designed two decades ago, they still rem ...

2021

Sublinear Bounds on the Distinguishing Advantage for Multiple Samples

Serge Vaudenay

The maximal achievable advantage of a (computationally unbounded) distinguisher to determine whether a source

Z

is distributed according to distribution

P_0

or

P_1

, when given access to one sample of

Z

, is characterized by the statistical distance ...

Springer, Cham2020

Secure, Confidential Blockchains Providing High Throughput and Low Latency

Eleftherios Kokoris Kogias

One of the core promises of blockchain technology is that of enabling trustworthy data dissemination in a trustless environment. What current blockchain systems deliver, however, is slow dissemination of public data, rendering blockchain technology unusabl ...

EPFL2019

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

Building Security Protocols Against Powerful Adversaries

Iris Safaka

As our sensitive data is increasingly carried over the Internet and stored remotely, security in communications becomes a fundamental requirement. Yet, today's security practices are designed around assumptions the validity of which is being challenged. In ...

EPFL2016

Affine-malleable Extractors, Spectrum Doubling, and Application to Privacy Amplification

Divesh Aggarwal

The study of seeded randomness extractors is a major line of research in theoretical computer science. The goal is to construct deterministic algorithms which can take a weak random source x with min-entropy k and a uniformly random seed Y of length d, and ...

Ieee2016

Secret Communication Over Broadcast Erasure Channels With State-Feedback

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

We consider a 1-to-K communication scenario, where a source transmits private messages to K receivers through a broadcast erasure channel, and the receivers feedback strictly, causally, and publicly their channel states after each transmission. We explore ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Secure Communication in Erasure Networks with State-feedback

László Czap

The security and efficiency of communication are two of the main concerns for networks of today and the future. Our understanding of how to efficiently send information over various channels and networks has significantly increased in the past decade (see ...

EPFL2014

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

Creating Secrets out of Erasures

Aikaterini Argyraki, Christina Fragouli, Suhas Diggavi, Panagiotis Kostopoulos

Current security systems often rely on the adversary's computational limitations. Wireless networks offer the opportunity for a different, complementary kind of security, which relies on the adversary's limited network presence (i.e., that the adversary ca ...

2013

Creating Shared Secrets out of Thin Air

Aikaterini Argyraki, Christina Fragouli, Suhas Diggavi, Iris Safaka

Current security systems typically rely on the adversary's computational limitations (e.g., the fact that it cannot invert a hash function or perform large-integer factorization). Wireless networks offer the opportunity for a different, complementary kind ...

Assoc Computing Machinery2012

Scalable and Secure Polling in Dynamic Distributed Networks

Rachid Guerraoui, Anne-Marie Kermarrec, Hamza Harkous, Florian Huc

We consider the problem of securely conducting a poll in synchronous dynamic networks equipped with a Public Key Infrastructure (PKI). Whereas previous distributed solutions had a communication cost of O(n^2) in an n nodes system, we present SPP (Secure an ...

2012

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

Equivalences and calculi for formal verification of cryptographic protocols

Johannes Borgström

Security protocols are essential to the proper functioning of any distributed system running over an insecure network but often have flaws that can be exploited even without breaking the cryptography. Formal cryptography, the assumption that the cryptograp ...

EPFL2008

Short 2-Move Undeniable Signatures

Serge Vaudenay, Jean Monnerat

Attempting to reach a minimal number of moves in cryptographic protocols is a quite classical issue. Besides the theoretical interests, minimizing the number of moves can clearly facilitate practical implementations in environments with communication const ...

2006