A study on quantum key expansion method based on Chaos

According to quantum key distribution of discrete variables, especially in the free space, it is difficult for single photon to be generated and detected, and high information transmission rate is no easy to get. This paper puts forward a kind of key expansion method based on chaos, initial key that is generated by information coordination is divided into blocks, and using Chaos system sensitivity for initial value can get new initial key with excellent performance. Experiments have proved that this method can effectively lengthen key and improve information transmission rate, at the same time, the new initial key has good randomness. Thus it can effectively reduce eavesdropper´s useful information from the initial key, and improve security of information transmission.