arXiv subjects

Qiao-Yan Wen

Publications and source records attributed to Qiao-Yan Wen.

47 records · Page 3Linked to original sources

arXiv2011

Dense-Coding Attack on Three-Party Quantum Key Distribution Protocols

Cryptanalysis is an important branch in the study of cryptography, including both the classical cryptography and the quantum one. In this paper we analyze the security of two three-party quantum key distribution protocols (QKDPs) proposed recently, and point out that they are susceptible to a simple and effective attack, i.e. the dense-coding attack. It is shown that the eavesdropper Eve can totally obtain the session key by sending entangled qubits as the fake signal to Alice and performing collective measurements after Alice's encoding. The attack process is just like a dense-coding communication between Eve and Alice, where a special measurement basis is employed. Furthermore, this attack does not introduce any errors to the transmitted information and consequently will not be discovered by Alice and Bob. The attack strategy is described in detail and a proof for its correctness is given. At last, the root of this insecurity and a possible way to improve these protocols are discussed.

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arXiv2011

Three-tangle for high-rank mixed states

A family of rank-n (n=5,6,7,8) three-qubit mixed states are constructed. The explicit expressions for the three-tangle and optimal decompositions for all these states are given. The CKW relations for these states are also discussed.

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arXiv2008

Quantum asymmetric cryptography with symmetric keys

Based on quantum encryption, we present a new idea for quantum public-key cryptography (QPKC) and construct a whole theoretical framework of a QPKC system. We show that the quantum-mechanical nature renders it feasible and reasonable to use symmetric keys in such a scheme, which is quite different from that in conventional public-key cryptography. The security of our scheme is analyzed and some features are discussed. Furthermore, the state-estimation attack to a prior QPKC scheme is demonstrated.

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arXiv2008

Revisiting the security of quantum dialogue and bidirectional quantum secure direct communication

From the perspective of information theory and cryptography, we analyze the security of two quantum dialogue protocols and a bidirectional quantum secure direct communication (QSDC) protocol, and point out that the transmitted information would be partly leaked out in them. That is, any eavesdropper can elicit some information about the secrets from the public annunciations of the legal users. This phenomenon should have been strictly forbidden in a quantum secure communication. In fact, this problem exists in quite a few recent proposals and, therefore, it deserves more research attention in the following related study.

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arXiv2008

Cryptanalysis of the Hillery-Buzek-Berthiaume quantum secret-sharing protocol

The participant attack is the most serious threat for quantum secret-sharing protocols. We present a method to analyze the security of quantum secret-sharing protocols against this kind of attack taking the scheme of Hillery, Buzek, and Berthiaume (HBB) [Phys. Rev. A 59 1829 (1999)] as an example. By distinguishing between two mixed states, we derive the necessary and sufficient conditions under which a dishonest participant can attain all the information without introducing any error, which shows that the HBB protocol is insecure against dishonest participants. It is easy to verify that the attack scheme of Karlsson, Koashi, and Imoto [Phys. Rev. A 59, 162 (1999)] is a special example of our results. To demonstrate our results further, we construct an explicit attack scheme according to the necessary and sufficient conditions. Our work completes the security analysis of the HBB protocol, and the method presented may be useful for the analysis of other similar protocols.

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arXiv2008

Consistency of shared reference frames should be reexamined

In a recent Letter [G. Chiribella et al., Phys. Rev. Lett. 98, 120501 (2007)], four protocols were proposed to secretly transmit a reference frame. Here We point out that in these protocols an eavesdropper can change the transmitted reference frame without being detected, which means the consistency of the shared reference frames should be reexamined. The way to check the above consistency is discussed. It is shown that this problem is quite different from that in previous protocols of quantum cryptography.

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arXiv2006

Fake one-time pad cannot be used to improve the efficiency of quantum communication

Two misuses of one-time pad in improving the efficiency of quantum communication are pointed out. One happens when using some message bits to encrypt others, the other exists because the key bits are not truly random. Both of them result in the decrease of security. Therefore, one-time pad should be used carefully in designing quantum communication protocols.

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arXiv2006

Improving the security of multiparty quantum secret sharing based on entanglement swapping against participant attack

In a recent paper [Z. J. Zhang and Z. X. Man, Phys. Rev. A 72, 022303(2005)], a multiparty quantum secret sharing protocol based on entanglement swapping was presented. However, as we show, this protocol is insecure in the sense that an unauthorized agent group can recover the secret from the dealer. Hence, we propose an improved version of this protocol which can stand against this kind of attack.

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arXiv2006

Threshold quantum cryptograph based on Grover's algorithm

Grover's operator in the two-qubit case can transform a basis into its conjugated basis. A permutation operator can transform a state in the two conjugated bases into its orthogonal state. These properties are included in a threshold quantum protocol. The proposed threshold quantum protocol is secure based the proof that the legitimate participators can only eavesdrop 2 bits of 3 bits operation information on one two-qubit with error probability 3/8. We propose a scheme to detect the Trojan horse attack without destroying the legal qubit.

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arXiv2006

Entanglement Split:Comment on ``Quantum secret sharing based on reusable Greenberger-Horne-Zeilinger states as secure carriers'' [Phys. Rev. A 67, 044302 (2003)]

In a recent paper [S. Bagherinezhad and V. Karimipour, Phys. Rev. A 67, 044302 (2003)], a quantum secret sharing protocol based on reusable GHZ states was proposed. However, in this comment, it is shown that this protocol is insecure because a cheater can gain all the secret bits before sharing, while introducing one data bit error at most in the whole communication, which makes the cheater avoid the detection by the communication parities.

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arXiv2006

Improving the security of quantum exam against cheating

The security of quantum exam [Phys. Lett. A 350 (2006) 174] is analyzed and it is found that this protocol is secure for any eavesdropper except for the "students" who take part in the exam. Specifically, any student can steal other examinees' solutions and then cheat in the exam. Furthermore, a possible improvement of this protocol is presented.

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