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

By changing the initial values in entangled Fibonacci-sequence spiral sources in Simon et al.'s (2013) experimental setup [13], we propose a controllable quantum private query protocol. Moreover, our protocol achieves flexible key expansion and even exhibits secure advantages during communications because of the following observations. We observe the close relationships between Lucas numbers and the first kind of Chebyshev maps, and the Chebyshev maps and k-Chebyshev maps; by adjusting the parameter m in k-Chebyshev maps, Alice and Bob can obtain their expected values of the key blocks and database respectively. (C) 2015 Elsevier B.V. All rights reserved.