Ruggero Morselli

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We present LMS, a protocol for efficient lookup on unstructured networks. Our protocol uses a virtual namespace <i>without imposing specific topologies</i>. It is more efficient than existing lookup protocols for unstructured networks, and thus is an attractive alternative for applications in which the topology cannot be structured as a Distributed Hash(More)
We revisit the following question: what are the minimal assumptions needed to construct statistically-hiding commitment schemes? Naor et al. show how to construct such schemes based on any one-way permutation. We improve upon this by showing a construction based on any approximable preimage-size one-way function. These are one-way functions for which it is(More)
The number and heterogeneity of requests to Web sites are increasing also because the Web technology is becoming the preferred interface for information systems. Many systems hosting current Web sites are complex architectures composed by multiple server layers with strong scalability and reliability issues. In this paper we compare the performance of(More)
We describe a method for performing trustpreserving set operations by untrusted parties. Our motivation for this is the problem of securely reusing content-based search results in peer-to-peer networks. We model search results and indexes as data sets. Such sets have value for answering a new query only if they are trusted. In the absence of any system-wide(More)
We propose a novel game-theoretic framework for analyzing the robustness of trust-inference protocols in the presence of adversarial (but rational) users. To the best of our knowledge, this is the first such framework which simultaneously (1) admits a rigorous and precise definition, thereby enabling formal proofs of security (in various adversarial(More)
A Certification Authority (CA) can be used to certify keys and build a public-key infrastructure (PKI) when all users trust the same CA. A decentralized PKI trades off absolute assurance on keys for independence from central control and improved scalability and robustness. The PGP “web of trust” model has been suggested as a decentralized certification(More)
Social networks, of which webs of trust are a particular type, have been shown to be effective ways of moving information with minimal external configuration, setup, or management. For applications requiring information assurance, a web of trust is an appealing system architecture, since trust is an inherent component of both the network design and(More)
P2P deployments are a natural infrastructure for building distributed search networks. Proposed systems support locating and retrieving all results, but lack the information necessary to rank them. Users, however, are primarily interested in the most relevant results, not necessarily all possible results. Using random sampling, we extend a class of(More)
Ring signatures, first introduced by Rivest, Shamir, and Tauman, enable a user to sign a message so that a ring of possible signers (of which the user is a member) is identified, without revealing exactly which member of that ring actually generated the signature. In contrast to group signatures, ring signatures are completely “ad-hoc” and do not require(More)