Patent ID: 7178277
Filing Date: 2007-02-20
Classification: H04L

Abstract:
1. A quantum cryptography communication system comprising: a first data communication unit; a second data communication unit connected with said first data communication unit; a third data communication unit connected with said first data communication unit; a fourth data communication unit connected with said second and third data communication units, respectively, wherein a first shared key is generated in said first data communication unit and said second data communication unit, a second shared key is generated in said second data communication unit and said fourth data communication unit, a third shared key is generated in said first data communication unit and said third data communication unit, a fourth shared key is generated in said third data communication unit and said fourth data communication unit, said first data communication unit encrypts said first shared key by using said third shared key to produce a composite key, encrypts said composite by using said first shared key, and then transmits said encrypted composite key to said second data communication unit, and said second data communication unit decrypts said encrypted composite key to reproduce said composite key, encrypts said composite by using said second shared key, and then transmits said encrypted composite key to said third data communication unit, said third data communication unit encrypts said third shared key by using said fourth shared key, and then transmits said encrypted third shared key to said fourth data communication unit, and said third data communication unit decrypts said encrypted third shared key by using said fourth shared key to reproduce said third shared key, decrypts said encrypted composite key by using said second shared key to reproduce said composite key, and decrypts said composite key by using said third shared key to reproduce said first shared key.