A Logical Key Hierarchy Based Approach to Preserve Content Privacy in Decentralized Online Social Networks

Andrea De Salve*, Roberto Di Pietro, Paolo Mori, Laura Ricci

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Distributed Online Social Networks (DOSNs) have been proposed to shift the control over user data from a unique entity, the online social network provider, to the users of the DOSN themselves. In this paper we focus on the problem of preserving the privacy of the contents shared to large groups of users. In general, content privacy is enforced by encrypting the content, having only authorized parties being able to decrypt it. When efficiency has to be taken into account, new solutions have to be devised that: i) minimize the re-encryption of the contents published in a group when the composition of the group changes; and, ii) enable a fast distribution of the cryptographic keys to all the members (nn) of a group, each time a set of users is removed from or added to the group by the group owner. Current solutions fall short in meeting the above criteria, while our approach requires only O(d\cdot logd (n))O(d·logd(n)) encryption operations when a user is removed from a group (where dd is an input parameter of the system), and O(2\cdot logd (n))O(2·logd(n)) when a user joins the group. The effectiveness of our approach is evaluated through simulations based on a real online social network.

Original languageEnglish (US)
Article number7987004
Pages (from-to)2-21
Number of pages20
JournalIEEE Transactions on Dependable and Secure Computing
Issue number1
StatePublished - Jan 1 2020

Bibliographical note

Publisher Copyright:
© 2004-2012 IEEE.


  • decentralized online social networks
  • group communication
  • Information privacy
  • key management

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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