Quantum public-key cryptosystem without quantum channel between any two users based on the Bell state measurement

Xiaoyu Li, Dai Wang 

School of Information Engineering, Zhengzhou University, Zhengzhou City, China

In this paper, a quantum public-key cryptosystem without quantum channel between any two users based on the Bell state measurement is presented. A user Alice shares a set of Einstein-Podolsky-Rosen (EPR) pairs with key management centre (KMC) as the private key and the public key. By performing the Bell state measurement on the public key and the auxiliary qubits any other user can send encrypted message to Alice. On the other hand, digital signature can also be achieved by this public-key cryptosystem. The laws of quantum physics guarantee the unconditional security of this public-key cryptosystem. No quantum channels are needed between any two users. So it is easier to carry out in practice and more robust against possible attacks.