Private database queries based on counterfactual quantum key distribution

Abstract

Based on the fundamental concept of quantum counterfactuality, we propose a protocol to achieve quantum private database queries, which is a theoretical study of how counterfactuality can be employed beyond counterfactual quantum key distribution (QKD). By adding crucial detecting apparatus to the device of QKD, the privacy of both the distrustful user and the database owner can be guaranteed. Furthermore, the proposed private-database-query protocol makes full use of the low efficiency in the counterfactual QKD, and by adjusting the relevant parameters, the protocol obtains excellent flexibility and extensibility.

Novel classical post-processing for quantum key distribution-based quantum private query

“…Similar to existing QKD-based QPQ protocols [11,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], our protocol is also cheatsensitive in terms of user privacy. The user privacy is based on the impossibility of perfectly distinguishing non-orthogonal quantum states and superluminal communication.…”

Counterfactual distribution of Schrödinger cat states

“…where |ψ A1B1 (|ψ A2B2 ) indicate the optical channel between Alice 1 (Alice 2 ) and Bob, evolves under the partial propagator (16) to…”

“…Since the proposal of the counterfactual key distribution protocol Noh-2009 (N09) [8], there has been an upsurge of interest in this area, leading to contributions devoted to improving its efficiency [9,10], to security considerations under various attacks [11][12][13], to modified communication schemes [14,15], applications [16][17][18] and experimental proposals or realizations [19].…”

Controllable quantum private queries using an entangled Fibonacci-sequence spiral source

“…In recent years, there has been a growing interest in quantum private queries (QPQ) [1][2][3][4][5][6][7][8][9]. QPQ are quantum protocols that provide symmetrical private information retrieval (SPIR), which is designed for the user and data privacy.…”