1 research outputs found
A Random Server Model for Private Information Retrieval (or How to Achieve Information Theoretic PIR Avoiding Data Replication)
Private information retrieval (PIR) schemes enable users to obtain
information from databases while keeping their queries secret from the
database managers. We propose a new model for PIR, utilizing
auxiliary random servers to provide privacy services for database
access. In this model, prior to any on-line communication where users
request queries, the database engages in an initial preprocessing
setup stage with the random servers. Using this model we achieve the
first PIR information theoretic solution in which the database does
not need to give away its data to be replicated, and with minimal
on-line computation cost for the database. This solves privacy and
efficiency problems inherent to all previous solutions.
In particular, all previous information theoretic PIR schemes required
multiple replications of the database into separate entities which are
not allowed to communicate with each other; and in all previous
schemes (including ones which do not achieve information theoretic
security), the amount of computation performed by the database on-line
for every query is at least linear in the size of the database.
In contrast, in our solutions the database does not give away its
contents to any other entity; and after the initial setup stage, which
costs at most O(n log n) in computation, the database needs to
perform only O(1) amount of computation to answer questions of users
on-line. All the extra on-line computation is done by the auxiliary
random servers