Privacy homomorphisms for social networks with private relationships
ABSTRACT Enabling private relationships in social networks is an important issue recently raised in the literature. We describe in this paper a new protocol which offers private relationships allowing resource access through indirect relationships without requiring a mediating trusted third party (although an optimistic trusted third party is used which only acts in case of conflict). Thanks to homomorphic encryption, our scheme prevents the resource owner from learning the relationships and trust levels between the users who collaborate in the resource access. In this way, the number of users who might refuse collaboration due to privacy concerns is minimized. This results in increased resource availability, as the chances that certain nodes become isolated at a given period of time are reduced. Empirical evidence is provided about the proposed protocol being scalable and deployable in practical social networks.
Full-textDOI: · Available from: Alexandre Viejo, May 23, 2015
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ABSTRACT: We introduce the novel concept of coprivacy or co-operative privacy to make privacy preservation attractive. A protocol is coprivate if the best option for a player to preserve her privacy is to help another player in preserving his privacy. Coprivacy makes an individual's privacy preservation a goal that rationally interests other individuals: it is a matter of helping oneself by helping someone else. We formally define coprivacy in terms of Nash equilibria. We then extend the concept to: i) general coprivacy, where a helping player's utility (i.e. interest) may include earning functionality and security in addition to privacy; ii) mixed coprivacy, where mixed strategies and mixed Nash equilibria are allowed with some restrictions; iii) correlated coprivacy, in which Nash equilibria are replaced by correlated equilibria. Coprivacy can be applied to any peer-to-peer (P2P) protocol. We illustrate coprivacy in P2P anonymous keyword search, in content privacy in social networks, in vehicular network communications and in controlled content distribution and digital oblivion enforcement.
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ABSTRACT: The technological advancements in Internet speeds, increased computing power and smart phones have pushed the rise of new digital methods supporting mobile person-to-person (P2P) payments. Despite the growing interest in these new methods, we be-lieve that, to fully enable this increasing rise of digital wallets, there is the need for tools helping a person in judging the risk of a money transfer. For this purpose, this paper aims at exploiting social net-work connections. This is achieved by making pay-ers/payees able to state their trust preferences with respect to the potential payees/payers. Trust pref-erence evaluation requires to find social connections between a payer and a payee across, possible, differ-ent social network realms. We therefore propose a light cryptography protocol, specifically targeted to mobile P2P payments, that besides providing good performance, ensures user information privacy.
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ABSTRACT: Because people usually establish their online social network based on their offline relationship, the social networks (i.e., the graph of friendship relationships) are often used to share contents. Mobile devices let it easier in these days, but it also increases the privacy risk such as access control of shared data and relationship exposure to untrusted server. To control the access on encrypted data and protect relationship from the server, M. Atallah et al. proposed a hop-based scheme in 2009. Their scheme assumed a distributed environment such as p2p, and each user in it shares encrypted data on their social network. On the other hand, it is very inefficient to keep their relationship private, so we propose an improved scheme. In this paper, among encrypted contents and relationships, some authenticated users can only access the data in distributed way. For this, we adopt 'circular-secure symmetric encryption' first. Proposed scheme guarantees the improved security and efficiency compared to the previous work.01/2012; 22(3).