基于Bell态的三方量子密钥协商

提出了基于两粒子纠缠态的一个三方量子密钥协商协议. 方案中的三个参与者是完全对等的, 且对建立的共享密钥具有相同的贡献. 除此之外, 三方中的任何一方或两方都不能事先单独决定共享密钥. 安全分析表明本协议既能抵抗外部窃听者的攻击, 又能抵抗内部参与者攻击. 关键词： 量子密码学 量子密钥协商 Bell态     

Quantum Dialogue with Authentication Based on Bell States

We propose an authenticated quantum dialogue protocol, which is based on a shared private quantum entangled channel. In this protocol, the EPR pairs are randomly prepared in one of the four Bell states for communication. By performing four Pauli operations on the shared EPR pairs to encode their shared authentication key and secret message, two legitimate users can implement mutual identity authentication and quantum dialogue without the help from the third party authenticator. Furthermore, due to the EPR pairs which are used for secure communication are utilized to implement authentication and the whole authentication process is included in the direct secure communication process, it does not require additional particles to realize authentication in this protocol. The updated authentication key provides the counterparts with a new authentication key for the next authentication and direct communication. Compared with other secure communication with authentication protocols, this one is more secure and efficient owing to the combination of authentication and direct communication. Security analysis shows that it is secure against the eavesdropping attack, the impersonation attack and the man-in-the-middle (MITM) attack.     

A New Secure Quantum Key Expansion Scheme

A new quantum key expansion scheme is proposed. The protocol of quantum key expansion proposed by Hwang is analyzed and the eavesdropping scheme is presented. We found that the using of the basis sequence shared by communicating parties is the weakness of the protocol. Hence we propose a ‘purification attack’ for the eavesdropper to steal partial information of the raw key and the new key between communicating parties. In view of this defect, we propose a new protocol of quantum key expansion, where the shared key is encrypted into a sequence of unitary operators which can be used securely against the presented attack.     

Improvement on “Quantum Key Agreement Protocol with Maximally Entangled States”

Recently, Hsueh and Chen [in Proceedings of the 14th Information Security Conference, National Taiwan University of Science and Technology, Taipei, pp. 236–242, 2004] proposed a quantum key agreement (QKA) protocol with maximally entangled states. Their protocol allows two users to negotiate a secret key in such a way that no one can predetermine the shared key alone. This study points out two security flaws in their protocol: (1) a legitimate but malicious user can fully control the shared key alone; (2) an eavesdropper can obtain the shared key without being detected. A possible solution is presented to avoid these attacks and also Tsai et al.’s CNOT attack [in Proceedings of the 20th Cryptology and Information Security Conference, National Chiao Tung University, Hsinchu, pp. 210–213, 2010] on Hsueh and Chen protocol to obtain the shared key without being detected.     

Security of Y-00 under heterodyne measurement and fast correlation attack

We provide a security analysis of the Y-00 protocol under heterodyne measurement and correlation attack. We show that the secrecy of the data encryption scheme is extremely sensitive to the running-key generation process. In many situations our simple attack succeeds in recovering the initial shared secret key. Our simulation results suggest that a truly secure implementation of the protocol should take into account the effective key generation method.     

智能卡和口令结合的动态认证方案

远程认证协议能有效的保证远程用户和服务器在公共网络上的通信安全。提出一种匿名的安全身份认证方案,通过登录 的动态变化,提供用户登录的匿名性,通过用户和服务器相互验证建立共享的会话密钥,抵抗重放攻击和中间人攻击,实现用户安全和隐私,通过BAN逻辑分析证明改进方案的有效性,通过安全性证明和性能分析说明了新协议比同类型的方案具有更高的安全性、高效性。     

Quantum secure direct communication with Greenberger-Horne-Zeilinger-type state （GHZ state） over noisy channels

We propose a quantum error-rejection scheme for direct communication with three-qubit quantum codes based on the direct communication of secret messages without any secret key shared in advance. Given the symmetric and independent errors of the transmitted qubits, our scheme can tolerate a bit of error rate up to 33.1%, thus the protocol is deterministically secure against any eavesdropping attack even in a noisy channel.     

Improvement of “Novel Multiparty Quantum Key Agreement Protocol with GHZ States”

Quantum key agreement (QKA) protocol is a method for negotiating a fair and secure key among mutually untrusted participants. Recently, Xu et al. (Quantum Inf. Process. 13:2587–2594, 2014) proposed a multi-party QKA protocol based on Greenberger-Horne-Zeilinger (GHZ) states. However, this study points out that Xu et al.’s protocol cannot provide the fairness property. That is, the last involved participant in the protocol can manipulate the final shared secret key without being detected by the other participants. Moreover, according to Yu et al.’s research (2015), Xu et al.’s protocol cannot avoid the public discussion attack too. To avoid these weaknesses, an improved QKA protocol is proposed.     

Three-Party Quantum Key Agreement Protocol Based on Continuous Variable Single-Mode Squeezed States

The difficulty of quantum key agreement is to realize its security and fairness at the same time.This paper presents a new three-party quantum key agreement protocol based on continuous variable single-mode squeezed state.The three parties participating in the agreement are peer entities,making same contributions to the final key.Any one or two participants of the agreement cannot determine the shared key separately.The security analysis shows that the proposed protocol can resist both external and internal attacks.     

Cryptanalysis of a Semi-Quantum Bi-Signature Scheme Based on W States

Recently, Zhao et al. proposed a semi-quantum bi-signature (SQBS) scheme based on W states with two quantum signers and just one classical verifier. In this study, we highlight three security issues with Zhao et al.’s SQBS scheme. In Zhao et al.’s SQBS protocol, an insider attacker can perform an impersonation attack in the verification phase and an impersonation attack in the signature phase to capture the private key. In addition, an eavesdropper can perform a man-in-the-middle attack to obtain all of the signer’s secret information. All of the above three attacks can pass the eavesdropping check. Without considering these security issues, the SQBS protocol could fail to ensure the signer’s secret information.     

Polarization Attack on Continuous-Variable Quantum Key Distribution with a Local Local Oscillator

The estimation of phase noise of continuous-variable quantum key distribution protocol with a local local oscillator (LLO CVQKD), as a major process in quantifying the secret key rate, is closely relevant to the intensity of the phase reference. However, the transmission of the phase reference through the insecure quantum channel is prone to be exploited by the eavesdropper (Eve) to mount attacks. Here, we introduce a polarization attack scheme against the phase reference. Presently, in a practical LLO CVQKD system, only part of the phase reference pulses are measured to compensate for the polarization drift of the quantum signal pulses in a compensation cycle due to the limited polarization measurement rate, while the other part of the phase reference pulses are not measured. We show that Eve can control the phase noise by manipulating the polarization direction of the unmeasured phase reference to hide her attack on the quantum signal. Simulations show that Eve can obtain partial or total key rates information shared between Alice and Bob as the transmission distance increases. Improving the polarization measurement rate to 100% or monitoring the phase reference intensity in real-time is of great importance to protect the LLO CVQKD from polarization attack.     

Three Attacks on the Mediated Semi-Quantum Key Distribution without Invoking Quantum Measurement

Semi-quantum key distribution is a very interesting new branch of quantum key distribution. It can be implemented when one or more participants are restricted to operate quantum states only on the quantum computational basis. Very recently, a mediated semi-quantum key distribution protocol without invoking two participants' quantum measurement has been proposed. The protocol allows two “classical” participants without sophisticated quantum capability to establish a shared secret key under an untrusted third party. It is claimed that the protocol is secure against several well-known attacks. However, in this paper, it is first pointed out that there exist three attacks “Measurement Attack, Modification Attack, and Collective Attack” on the mediated semi-quantum key distribution protocol without invoking quantum measurement. By proposed attacks, a malicious third party can obtain the secret key without being noticed by legitimated participants.     

Multiparty Quantum Key Agreement with Four-Qubit Symmetric W State

Based on four-qubit symmetric W state, the delayed measurement, decoy photos method, block transmission technique and the dense coding method, a multi-party quantum key agreement protocol is proposed. By utilizing the delayed measurement and decoy photos method, the fairness and security of the protocol are ensured. That is, the final generation key can be got fairly by m participants and the outside eavesdropper (includes Trojan-horse attacks, Measure-resend attack, Intercept-resend attack and Entangle-measure attack) and the dishonest participants attacks can be resisted in this protocol. By utilizing block transmission technique and the dense coding method, the efficiency of the protocol is improved. The efficiency analysis shows that the proposed protocol is more efficient than other multi-party QKA protocols.     

Novel Multi-Party Quantum Key Agreement Protocol with G-Like States and Bell States

A significant aspect of quantum cryptography is quantum key agreement (QKA), which ensures the security of key agreement protocols by quantum information theory. The fairness of an absolute security multi-party quantum key agreement (MQKA) protocol demands that all participants can affect the protocol result equally so as to establish a shared key and that nobody can determine the shared key by himself/herself. We found that it is difficult for the existing multi-party quantum key agreement protocol to withstand the collusion attacks. Put differently, it is possible for several cooperated and untruthful participants to determine the final key without being detected. To address this issue, based on the entanglement swapping between G-like state and Bell states, a new multi-party quantum key agreement protocol is put forward. The proposed protocol makes full use of EPR pairs as quantum resources, and adopts Bell measurement and unitary operation to share a secret key. Besides, the proposed protocol is fair, secure and efficient without involving a third party quantum center. It demonstrates that the protocol is capable of protecting users’ privacy and meeting the requirement of fairness. Moreover, it is feasible to carry out the protocol with existing technologies.     

New Probabilistic Quantum Key Distribution Protocol

On the basis of entanglement swapping of Bell states, Hwang et al. proposed a probabilistic quantum key distribution (PQKD) protocol Quantum Inf. Comput. 11(7-8), 615–637 (2011). Recently, Lin et al. Quantum Inf. Comput. 14(9-10), 757–762 (2014) proposed a unitary operation attack on Hwang et al.’s PQKD. However, unlike the unitary operation attack, this work points out that a malicious participant in Hwang et al.’s PQKD protocol can manipulate the secret key. As a result, the security requirements of a PQKD protocol, i.e., fairness, cannot be satisfied in their protocol. Moreover, the same attack can also crack the fairness requirement of the existing quantum key agreement (QKA) protocols. To overcome both problems, this paper proposes a new PQKD protocol based on the order rearrangement of the transmitted photons. Furthermore, the rearrangement method can also solve the key manipulation attack in QKA protocols.     

Mediated Semi‐Quantum Key Distribution Without Invoking Quantum Measurement

This paper proposes a new semi‐quantum key distribution protocol, allowing two “classical” participants without sophisticated quantum capability to establish a shared secret key under an untrusted third party (a quantum server). The proposed protocol is free from several well‐known attacks. Furthermore, the efficiency is better than the existing three‐party SQKD protocol in which the classical participants must have the quantum measurement capability.     

Quantum key distribution in a single-photon regime with nonorthogonal basis states

A quantum key distribution protocol with nonorthogonal basis states is a generalization of the known BB84 key distribution protocol. The critical error and length of a secure key have been determined for the protocol with nonorthogonal basis states for an arbitrary angle between information states. An explicit optimal attack on the distributed key has been constructed; this attack maximizes eavesdropper information at a given error on the receiver side.     

Improvement on ‘Multiparty Quantum Key Agreement with Four-Qubit Symmetric W State’

Recently, Wang et al. (Int J Theo Phys: pp. 3716–3726, 2018) proposed a multiparty quantum key agreement scheme with four-particles W state. Their protocol uses the delayed measurement technique, the block transmission technique, and the single decoy photon technique to determine a shared secret key between three or more participants. They claimed that their protocol could resist both internal/participant and external attacks. However, this work indicates that two dishonest participants can collude to get the private data of a participant who executes the protocol honestly. To solve this issue, a simple modification is suggested in this work.

     

Quantum identity authentication based on ping-pong technique for photons

To prevent active attack, an one-way quantum identity authentication scheme is proposed by employing mechanism of ping-pong protocol and property of quantum controlled-NOT gate. It can verify the user's identity as well as distribute an updated key as the authentication key. Analytical results show the proposed scheme is secure under general individual attack.     

Multi-party Quantum Key Agreement without Entanglement

A new efficient quantum key agreement protocol without entanglement is proposed. In this protocol, each user encodes his secret key into the traveling particles by performing one of four rotation operations that one cannot perfectly distinguish. In the end, all users can simultaneously obtain the final shared key. The security of the presented protocol against some common attacks is discussed. It is shown that this protocol can effectively protect the privacy of each user and satisfy the requirement of fairness in theory. Moreover, the quantum carriers and the encoding operations used in the protocol can be achieved in realistic physical devices. Therefore, the presented protocol is feasible with current technology.