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The security proof of the ping-pong protocol is wrong (2008).
| Content Provider | CiteSeerX |
|---|---|
| Author | Zhang, Zhan-Jun |
| Abstract | In 2002, Bostrom and Felbinger presented a novel quantum secure direct communication protocol (named often as ping-pong protocol) [1] with a security proof in the case of ideal quantum channel. In this paper, we will show that the security proof is wrong in the strict sense. To prove the security of their protocol, Bostrom and Felbinger assume that Eve adds an ancilla in the state χ 〉 and performs a unitary operation Ê on the composite system consisting of the travel qubit and the ancilla. Then they worked out the von-Neumann entropy S of the state of the travel qubit after Eve’s attack operation and after Alice’s encoding operation. Von-Neumann entropy S is taken as the maximal amount I0 of classical information that can be extracted from a state. After some deductions, they got function I0(d), where d is the detection probability for Eve’s attack. By analyzing I0(d), they conclude that any effective eavesdropping attack can be detected. However, it should be emphasized that in Ref.[1] the I0 is extracted from the travel-qubit state. This is clearly stated by Bostrom and Felbinger themselves nearby the equation 8 in Ref.[1]. Incidentally, if the equations 7 and 8 in Ref.[1] denote the compositesystem state, then the calculation of S is wrong according to Ref.[2]. As will also lead to the fact that the security proof is wrong. About Bostrom and Felbinger’s proof, there exists a very serious question: Is it reasonable to assume in |
| File Format | |
| Publisher Date | 2008-01-01 |
| Access Restriction | Open |
| Subject Keyword | Security Proof Ping-pong Protocol Von-neumann Entropy Travel Qubit Travel-qubit State Compositesystem State Strict Sense Effective Eavesdropping Attack Composite System Serious Question Unitary Operation Function I0 Eve Attack Ideal Quantum Channel Maximal Amount I0 Classical Information Detection Probability Attack Operation |
| Content Type | Text |
