Secure Ping-Pong quantum key distribution protocol with 33.3% bit error rate

The security of the previous quantum key distribution protocols, which is guaranteed by the nature of physics law, is based on the legitimate users. However, the impersonation of Alice or Bob by eavesdropper, in practice. will be existed in a large probability. In this paper an improvement scheme for the security quantum key is proposed.

This paper has been withdrawn due to security loophole. We thank Dr G. P. he for pointing this to us.

This paper has been withdrawn by the author due to a crucial error in eq.59. I apologize for the inconveniences.

We propose a quantum key distribution protocol with quantum based user authentication. Our protocol is the first one in which users can authenticate each other without previously shared secret and then securely distribute a key where the key may not be exposed to even a trusted third party. The security of our protocol is guaranteed by the properties of the entanglement.

It is widely believed that quantum key distribution (QKD) has been proved unconditionally secure for realistic models applicable to various current experimental schemes. Here we summarize briefly why this is not the case, from both the viewpoints of fundamental quantitative security and applicable models of security analysis, with some morals drawn.

This paper has been withdrawn: it does not evade the no-go results of Mayers, Lo and Chau, to whom I am most grateful for helpful correspondences.

This paper has been temporarily withdrawn by the authors.

This paper has been withdrawn due to a fatal error in the argument of the simulation scheme.

This paper has been withdrawn.

This paper has been withdrawn by the author due to a crucial error.