5 research outputs found
Weakly-Private Information Retrieval
Private information retrieval (PIR) protocols make it possible to retrieve a file from a database without disclosing any information about the identity of the file being retrieved. These protocols have been rigorously explored from an information-theoretic perspective in recent years. While existing protocols strictly impose that no information is leaked on the file’s identity, this work initiates the study of the tradeoffs that can be achieved by relaxing the requirement of perfect privacy. In case the user is willing to leak some information on the identity of the retrieved file, we study how the PIR rate, as well as the upload cost and access complexity, can be improved. For the particular case of replicated servers, we propose two weakly-private information retrieval schemes based on two recent PIR protocols and a family of schemes based on partitioning. Lastly, we compare the performance of the proposed schemes
Weakly-Private Information Retrieval
Private information retrieval (PIR) protocols make it possible to retrieve a
file from a database without disclosing any information about the identity of
the file being retrieved. These protocols have been rigorously explored from an
information-theoretic perspective in recent years. While existing protocols
strictly impose that no information is leaked on the file's identity, this work
initiates the study of the tradeoffs that can be achieved by relaxing the
requirement of perfect privacy. In case the user is willing to leak some
information on the identity of the retrieved file, we study how the PIR rate,
as well as the upload cost and access complexity, can be improved. For the
particular case of replicated servers, we propose two weakly-private
information retrieval schemes based on two recent PIR protocols and a family of
schemes based on partitioning. Lastly, we compare the performance of the
proposed schemes.Comment: To be presented at 2019 IEEE International Symposium on Information
Theory (ISIT
The Capacity of Single-Server Weakly-Private Information Retrieval
A private information retrieval (PIR) protocol guarantees that a user can
privately retrieve files stored in a database without revealing any information
about the identity of the requested file. Existing information-theoretic PIR
protocols ensure perfect privacy, i.e., zero information leakage to the servers
storing the database, but at the cost of high download. In this work, we
present weakly-private information retrieval (WPIR) schemes that trade off
perfect privacy to improve the download cost when the database is stored on a
single server. We study the tradeoff between the download cost and information
leakage in terms of mutual information (MI) and maximal leakage (MaxL) privacy
metrics. By relating the WPIR problem to rate-distortion theory, the
download-leakage function, which is defined as the minimum required download
cost of all single-server WPIR schemes for a given level of information leakage
and a fixed file size, is introduced. By characterizing the download-leakage
function for the MI and MaxL metrics, the capacity of single-server WPIR is
fully described.Comment: To appear in IEEE Journal of Selected Areas in Information Theory
(JSAIT), Special Issue on Privacy and Security of Information Systems, 202