Quantum Private Query Protocol Based on EPR Pairs

We propose a Quantum private query (QPQ) protocol based on device-independent Quantum key distribution (QKD) by using Einstein-Podolsky-Rosen (EPR) pairs. We analyze coherent attacks by a third party in a weaker constraints (non-signaling condition) compared with the formalism of quantum physics. We deduce the relationship between the raw key bits of Alice and the third party's attack factor. Compared with existing QPQ protocols, our protocol is secure even when the source and measuring equipment used to distribute oblivious secret key can not be trusted. Quantum register is not needed in our protocol.