Résumé | Users of large scale distributed systems deployed in the public domain
do misbehave: MMOG players cheat, file sharing system users free-ride,
and social network users create multiple identities or try to
impersonate people they know. Traditional techniques to deal with
malicious users consist in masking their misbehaviors (e.g., BFT) or
preventing them (e.g., using cryptography). This talk presents dissuasive
methods against malicious behaviors based on distributed verifications:
users check each others actions and report detected faults. We first
illustrate our approach by analyzing an epidemic high-bandwidth
dissemination protocol where the inherent randomness of gossip protocols
allows lightweight collusion-resilient tracking of free-riders. We then
present our work on secured distributed computations in social networks
where the real persons' reputation concern acts as an incentive not to
misbehave.
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