Convert Communication Based On Quantum Cryptography

Nowday, with the rapid development of information technology, communication security has become an essential requirement for information security. However, both encrypted communication and convert communication, which are based on cryptographic systems, cannot guarantee unconditional security. They also have no capacity to check the simple eavesdropping. Therefore, quantum cryptography is proposed for its two basic properties: unconditional security and eavesdropping detectability.Convert communication, which serves as a basic module to design cryptography protocols, is widely used in practical application. To satisfy the special requirements in the wide applications of military communication and E-commerce, convert communication is well studied. However, the classical convert communication cannot guarantee the unconditional security and detectability. As a result, the research on quantum convert communication is of great significance.In this thesis, we have proposed several quantum convert communication protocols, which adopt the No-cloning Theory and Heisenberg Uncertainty Principle. The main contributions of this thesis are as follows:First, we are the first to introduce the concept of quantum convert communication. Then, the protocol based on quantum dense coding and the prisoner's problem is proposed. Different from classical convert communication schemes and current quantum communication schemes, our schemes could not only guarantee the unconditional security and detect the eavesdropping effectively, but also conceal the fact that a message is very existence.Second, this thesis is the first to propose a quantum convert communication protocol based on the redundancy. Different from existing convert communication protocols, our scheme could guarantee the unconditionally security and detect the eavesdropping effectively. To achieve that, quantum dense coding and quantum teleportation are adopted in our protocol.Third, to the best of our knowledge, we are the first to apply the quantum convert communication protocol which is based on GHZ identity authentication to E-payment systems. Different from existing convert communication protocols, our scheme could detect the eavesdropping effectively, and guarantee the unconditionally security and anonymity. To achieve that, we introduce the quantum cryptography into the protocol and identify the two parts who communicate with each other by making use of the GHZ triplet state. After making the identification, it is able to realize the quantum convert communication by combining the shared redundant photon during the period of identification and the quantum dense coding. This scheme could be applied to electronic cash system, for the convert communication between banks and customers.The proposed protocols are of profound theoretical significance. With the development of quantum experimenting technology, our protocols will get widespread applications.