Giuseppe Persiano

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We study the problem of searching on data that is encrypted using a public key system. Consider user Bob who sends email to user Alice encrypted under Alice’s public key. An email gateway wants to test whether the email contains the keyword “urgent” so that it could route the email accordingly. Alice, on the other hand does not wish to give the gateway the(More)
Non-Interactive Zero Knowledge (NIZK), introduced by Blum, Feldman, and Micali in 1988, is a fundamental cryptographic primitive which has attracted considerable attention in the last decade and has been used throughout modern cryptography in several essential ways. For example, NIZK plays a central role in building provably secure public-key cryptosystems(More)
This paper investigates the possibility of disposing of interaction between prover and verifier in a zero-knowledge proof if they share beforehand a short random string. Without any assumption, it is proven that noninteractive zero-knowledge proofs exist for some number-theoretic languages for which no efficient algorithm is known. If deciding quadratic(More)
We consider the problem of scheduling jobs on parallel related machines owned by selfish agents. We provide deterministic polynomial-time (2 + ǫ)-approximation algorithms and suitable payment functions that yield truthful mechanisms for several NP-hard restrictions of this problem. Up to our knowledge, our result is the first non-trivial polynomial-time(More)
We consider the following pebble motion problem. We are given a tree T with n vertices and two arrangements $\cal R$ and $\cal S$ of k<n distinct pebbles numbered 1, . . ., k on distinct vertices of the tree. Pebbles can move along edges of T provided that at any given time at most one pebble is traveling along an edge and each vertex of T contains at most(More)
We study combinatorial optimization problems involving one-parameter selfish agents considered by Archer and Tardos [FOCS 2001]. In particular, we show that, if agents can lie in one direction (that is they either overbid or underbid) then any (polynomial-time) capproximation algorithm, for the optimization problem without selfish agents, can be turned into(More)