Quantum Private Information Retrieval

Locally Decodable Codes are error-correcting codes which make it possible to recover entries from the original string by only looking at a certain number of entries from the codeword. In Private Information Retrieval a user wants to get data from a database without giving any information about the data she is interested in. The goal is to minimise the amount of communication which takes place between the user and the database. For a database on a single server the trivial protocol of sending the whole database is optimal [9], but when the database is replicated over a number of non-communicating servers much better schemes exist. There is a connection between Locally Decodable Codes and Private Information Retrieval in the sense that they can be converted into each other. The best known Private Information Retrieval Schemes are derived from Locally Decodable Codes. Allowing quantum bits as communication yields better Private Information Retrieval Schemes. Title: Quantum Private Information Retrieval Author: Klaas Ruben Brokkelkamp, rubenbrokkelkamp@gmail.com, 6282628 Supervisor: Prof. Ronald de Wolf Second examiner: Prof. Hans Maassen Date: July 19, 2013 The cover image is taken from Bianca Kramer, Information retrieval and literature searching in today’s information landscape, http://journals.sfu.ca/ hypot/index.php/main/article/view/182. University of Amsterdam Science Park 904 1098 XH Amsterdam