Paper 2015/364

Privacy-preserving Context-aware Recommender Systems: Analysis and New Solutions

Qiang Tang and Jun Wang

Abstract

Nowadays, recommender systems have become an indispensable part of our daily life and provide personalized services for almost everything. However, nothing is for free -- such systems have also upset the society with severe privacy concerns because they accumulate a lot of personal information in order to provide recommendations. In this work, we construct privacy-preserving recommendation protocols by incorporating cryptographic techniques and the inherent data characteristics in recommender systems. We first revisit the protocols by Jeckmans et al. at ESORICS 2013 and show a number of security and usability issues. Then, we propose two privacy-preserving protocols, which compute predicted ratings for a user based on inputs from both the user's friends and a set of randomly chosen strangers. A user has the flexibility to retrieve either a predicted rating for an unrated item or the Top-N unrated items. The proposed protocols prevent information leakage from both protocol executions and the protocol outputs: a somewhat homomorphic encryption scheme is used to make all computations run in encrypted form, and inputs from the randomly-chosen strangers guarantee that the inputs of a user's friends will not be compromised even if this user's outputs are leaked. Finally, we use the well-known MovieLens 100k dataset to evaluate the performances for different parameter sizes.

Metadata
Available format(s)
PDF
Category
Applications
Publication info
Preprint. MINOR revision.
Keywords
recommender systemshomomorphic encryptionkey recovery attacks
Contact author(s)
qiang tang @ uni lu
History
2015-04-23: received
Short URL
https://ia.cr/2015/364
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2015/364,
      author = {Qiang Tang and Jun Wang},
      title = {Privacy-preserving Context-aware Recommender Systems: Analysis and New Solutions},
      howpublished = {Cryptology ePrint Archive, Paper 2015/364},
      year = {2015},
      note = {\url{https://eprint.iacr.org/2015/364}},
      url = {https://eprint.iacr.org/2015/364}
}
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