Title
Privacy-preserving matrix factorization
Abstract
Recommender systems typically require users to reveal their ratings to a recommender service, which subsequently uses them to provide relevant recommendations. Revealing ratings has been shown to make users susceptible to a broad set of inference attacks, allowing the recommender to learn private user attributes, such as gender, age, etc. In this work, we show that a recommender can profile items without ever learning the ratings users provide, or even which items they have rated. We show this by designing a system that performs matrix factorization, a popular method used in a variety of modern recommendation systems, through a cryptographic technique known as garbled circuits. Our design uses oblivious sorting networks in a novel way to leverage sparsity in the data. This yields an efficient implementation, whose running time is O(Mlog^2M) in the number of ratings M. Crucially, our design is also highly parallelizable, giving a linear speedup with the number of available processors. We further fully implement our system, and demonstrate that even on commodity hardware with 16 cores, our privacy-preserving implementation can factorize a matrix with 10K ratings within a few hours.
Year
DOI
Venue
2013
10.1145/2508859.2516751
ACM Conference on Computer and Communications Security
Keywords
Field
DocType
recommender system,modern recommendation system,efficient implementation,matrix factorization,ratings user,available processor,privacy-preserving implementation,recommender service,revealing rating,ratings m. crucially,recommender systems,privacy
Recommender system,Sorting network,Computer security,Cryptography,Computer science,Inference,Matrix (mathematics),Matrix decomposition,Theoretical computer science,Factorization,Speedup
Conference
Citations 
PageRank 
References 
79
1.90
48
Authors
6
Name
Order
Citations
PageRank
Valeria Nikolaenko133210.45
Stratis Ioannidis271551.97
Udi Weinsberg345422.51
Marc Joye42413170.74
Nina Taft52109154.92
Dan Boneh6212541398.98