Quantum Inf Process (2015) 14:1017–1024
Private database queries using one quantum state
Yu-Guang Yang · Ming-Ou Zhang · Rui Yang
Received: 2 March 2014 / Accepted: 15 December 2014 / Published online: 23 December 2014
© Springer Science+Business Media New York 2014
Abstract A novel private database query protocol with only one quantum state is
proposed. The database owner Bob sends only one quantum state to the user Alice.
The proposed protocol combines the idea of semiquantum key distribution and private
query. It can be implemented in the situation where not all the parties can afford
expensive quantum resources and operations. So our proposal is more practical in use.
We also prove that the proposed protocol is secure in terms of the user security and
the database security.
Keywords Quantum private query · Semiquantum key distribution · User security ·
Privacy is a major security problem in many applications. For example, in database
query, the user, Alice, wants to retrieve an item from a database, but does not want
the database holder, Bob to know which item she wants (user privacy). Also, Bob
would like not to disclose more information than what Alice has paid for (database pri-
vacy). The problem has been formalized as symmetrically private information retrieval
(SPIR) by Gerther et al. . SPIR problem is just a generalization of the private infor-
mation retrieval (PIR) problem , which deals with user privacy alone.
Y. - G . Ya ng (
) · M.-O. Zhang · R. Yang
College of Computer Science and Technology, Beijing University of Technology,
Beijing 100124, China
Y. - G . Ya ng
State Key Laboratory of Information Security Institute of Information Engineering,
Chinese Academy of Sciences, Beijing 100093, China