Research On Quantum Proxy Signature Scheme Based On Entanglement Swapping

The beginning of the network information age make the communication become more and more convenient and frequent. However, when we enjoy the convenience at the same time, how to protect personal privacy and information security become increasingly prominent, and cryptography play an important role in this issue.Digital signature, which is a digital simulation of handwritten signature, is the main part of cryptography and information security. It has experienced from the classical signature to quantum digital signature, and the main difference is the way that how to guarantee the security of the signature scheme:in traditional cryptography, its security is mainly based on the computational complexity and difficult math problems; in quantum cryptography, its security is based on the uncertainty principle of quantum states and not on the physical properties of cloning theorem. Because the generation of the quantum computer, quantum cryptography poses a great threat to the security of the digital signature scheme in the classical cryptography, and it is becoming a hot spot to many scholars.Our thesis mainly study quantum signature scheme and quantum proxy signature scheme based on the exchange of entanglement of the quantum state, the main results are as follows:In chapter 3, we propose a proxy signature scheme based on quantum entanglement swapping; it refers to a situation that when the original signers cannot work their right of the signature, they will delegate proxy signers to generate a valid signature.Compared with other schemes, bell state is easy to set up, so the implement ation complexity is reduced. We only use the two-particle entangled state, so the reso urce is saved. Security analysis shows that our scheme satisfies unconditional security, unforgeability and undeniability.In chapter 4, we propose a proxy-blind signature scheme based on quantum entanglement swapping; Blind signature makes use of one-time quantum encryption algorithm, not only ensure the quantum unconditional security, but also meet the blind signature non-repudiation and unforgeability. and so on.