Home

Person

Rachid Guerraoui

About
Privacy
Disclaimer

Graph Chatbot

Related publications (292)

Finding Trojan Message Vulnerabilities in Distributed Systems

Rachid Guerraoui, George Candea, Radu Banabic

Trojan messages are messages that seem correct to the receiver but cannot be generated by any correct sender. Such messages constitute major vulnerability points of a distributed system---they constitute ideal targets for a malicious actor and facilitate f ...

ACM2014

Personalizing Top-k Processing Online in a Peer-to-Peer Social Tagging Network

Rachid Guerraoui, Anne-Marie Kermarrec

The rapidly increasing amount of user-generated content in social tagging systems provides a huge source of information. Yet, performing effective search in these systems is very challenging, especially when we seek the most appropriate items that match a ...

Assoc Computing Machinery2014

The PCL Theorem. Transactions cannot be Parallel, Consistent and Live

Rachid Guerraoui, Victor Bushkov, Panagiota Fatourou

We show that it is impossible to design a transactional memory system which ensures parallelism, i.e. transactions do not need to synchronize unless they access the same application objects, while ensuring very little consistency, i.e. a consistency condit ...

2014

Privacy-Preserving Distributed Collaborative Filtering

Rachid Guerraoui, Anne-Marie Kermarrec, Davide Frey

We propose a new mechanism to preserve privacy while leveraging user profiles in distributed recommender systems. Our mechanism relies on (i) an original obfuscation scheme to hide the exact profiles of users without significantly decreasing their utility, ...

Springer International Publishing2014

Tracking freeriders in gossip-based content dissemination systems

Rachid Guerraoui, Maxime Monod, Anne-Marie Kermarrec, Kévin Clément Huguenin

Gossip-based protocols have proven very efficient for disseminating high-bandwidth content such as video streams in a peer-to-peer fashion. However, for the protocols to work, nodes are required to collaborate by devoting a fraction of their upload bandwid ...

Elsevier2014

Computing in social networks

Rachid Guerraoui, Anne-Marie Kermarrec, Kévin Clément Huguenin, Andrei Giurgiu

This paper defines the problem of Scalable Secure computing in a Social network: we call it the S-3 problem. In short, nodes, directly reflecting on associated users, need to compute a symmetric function f : V-n -> U of their inputs in a set of constant si ...

Elsevier2014

Tight Bounds for Asynchronous Renaming

Rachid Guerraoui, Seth Gilbert, Dan Alistarh

This article presents the first tight bounds on the time complexity of shared-memory renaming, a fundamental problem in distributed computing in which a set of processes need to pick distinct identifiers from a small namespace. We first prove an individual ...

Association for Computing Machinery2014

Democratizing Transactional Programming

Rachid Guerraoui, Vincent Gramoli

Association for Computing Machinery2014

Disjoint-Access Parallelism Does Not Entail Scalability

Rachid Guerraoui, Mihai Letia

Disjoint Access Parallelism (DAP) stipulates that operations involving disjoint sets of memory words must be able to progress independently, without interfering with each other. In this work we argue towards revising the two decade old wisdom saying that D ...

2014

A Distributed Polling with Probabilistic Privacy

Rachid Guerraoui, Yahya Benkaouz, Florian Huc

In this paper, we present PDP, a distributed polling protocol that enables a set of participants to gather their opinion on a common interest without revealing their point of view. PDP does not rely on any centralized authority or on heavyweight cryptograp ...

2013

Composing Relaxed Transactions

Rachid Guerraoui, Vincent Gramoli, Mihai Letia

As the classic transactional abstraction is sometimes considered too restrictive in leveraging parallelism, a lot of work has been devoted to devising relaxed transactional models with the goal of improving concurrency. Nevertheless, the quest for improvin ...

IEEE Computer Society2013

WHATSUP: A Decentralized Instant News Recommender

Rachid Guerraoui, Anne-Marie Kermarrec, Davide Frey

We present WhatsUp, a collaborative filtering system for disseminating news items in a large-scale dynamic setting with no central authority. WhatsUp constructs an implicit social network based on user profiles that express the opinions of users about the ...

2013

Fast Byzantine Agreement

Rachid Guerraoui, Florian Huc

This paper presents the first probabilistic Byzantine Agreement algorithm whose communication and time complexities are poly-logarithmic. So far, the most effective probabilistic Byzantine Agreement algorithm had communication complexity and time complexit ...

2013

Byzantine Agreement with Homonyms

Rachid Guerraoui, Eric Ruppert, Anne-Marie Kermarrec

So far, the distributed computing community has either assumed that all the processes of a distributed system have distinct identifiers or, more rarely, that the processes are anonymous and have no identifiers. These are two extremes of the same general mo ...

Springer2013

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

Early Deciding Synchronous Renaming in O( logf ) Rounds or Less

Rachid Guerraoui, Hagit Albo Attiya, Dan Alistarh

Renaming is a fundamental problem in distributed computing, in which a set of n processes need to pick unique names from a namespace of limited size. In this paper, we present the first early-deciding upper bounds for synchronous renaming, in which the run ...

Springer Berlin Heidelberg2012

Of Choices, Failures and Asynchrony: The Many Faces of Set Agreement

Rachid Guerraoui, Seth Gilbert, Dan Alistarh

Set agreement is a fundamental problem in distributed computing in which processes collectively choose a small subset of values from a larger set of proposals. The impossibility of fault-tolerant set agreement in asynchronous networks is one of the seminal ...

2012

Special section with selected papers from PODC 2010

Rachid Guerraoui

Springer Verlag2012

Decentralized polling with respectable participants

Rachid Guerraoui, Maxime Monod, Anne-Marie Kermarrec, Kévin Clément Huguenin

We consider the polling problem in a social network: participants express support for a given option and expect an outcome reflecting the opinion of the majority. Individuals in a social network care about their reputation: they do not want their vote to b ...

Elsevier2012

Of Choices, Failures and Asynchrony: The Many Faces of Set Agreement

Rachid Guerraoui, Seth Gilbert, Dan Alistarh

2012

Page 9 of 15