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Private Discovery of Common Social Contacts

Cristofaro, ED, Manulis, Mark and Poettering, B (2011) Private Discovery of Common Social Contacts In: 9th International Conference on Applied Cryptography and Network Security (ACNS 2011), 2011-06-07 - 2011-06-10, Nerja, Spain.

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The increasing use of computing devices for social interactions propels the proliferation of online social applications, yet, it prompts a number of privacy concerns. One common problem occurs when two unfamiliar users, in the process of establishing social relationships, want to assess their social proximity by discovering mutual contacts. In this paper, we introduce Private Contact Discovery, a novel cryptographic primitive that lets two users, on input their respective contact lists, learn their common contacts (if any), and nothing else. We present an efficient and provably secure construction, that (i) prevents arbitrary list manipulation by means of contact certification, and (ii) guarantees user authentication and revocability. Following a rigorous cryptographic treatment of the problem, we define the privacy-protecting contact-hiding property and prove it for our solution, under the RSA assumption in the Random Oracle Model (ROM). We also show that other related cryptographic techniques, such as Private Set Intersection and Secret Handshakes, are unsuitable in this context. Experimental analysis attests to the practicality of our technique, which achieves computational and communication overhead (almost) linear in the number of contacts.

Item Type: Conference or Workshop Item (Conference Paper)
Divisions : Faculty of Engineering and Physical Sciences > Computer Science
Authors :
Cristofaro, ED
Poettering, B
Date : 2011
DOI : 10.1007/978-3-642-21554-4_9
Contributors :
ContributionNameEmailORCID Berlin Heidelberg,
Additional Information : The original publication is available at
Depositing User : Symplectic Elements
Date Deposited : 12 Jun 2013 13:42
Last Modified : 06 Jul 2019 05:12

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