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Security of Quantum Cryptography Against Trojan Horse Attacking

Zeng Gui

Published Jan 1, 2004• 1 citation
OpenAlex

Abstract

Trojan horse attacking strategy on quantum cryptography is investigated. First, the fragility of the quantum cryptographic algorithm employing EPR (Einstein-Podosky-Rosen) pairs as a key against the Trojan horse attacking strategy is analyzed. To prevent the Trojan horse attacking, an improved scheme which makes use of the non-orthogonal entangled states is proposed. This scheme is robust to the Trojan horse attacking, without reducing the security on other kinds of attacking strategies.

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Trojan horse attack is a common eavesdropping strategy which can attack various quantum secure communication systems. Its basic idea is to send auxiliary photons into a legitimate communicator's apparatuses and steal information by analyzing the reflected photons. In this paper, we consider a different kind of Trojan horse attack, the so-called counterfactual Trojan horse attack, which has not been studied in detail so far. In such an attack, the eavesdropper may steal the secret information by ``ghost'' photons, which can spontaneously avoid being detected, even if the detector is an ideal one. We present the details and requirements of such an attack. We also illustrate our results by considering two protocols, the ping-pong protocol and the counterfactual quantum cryptography. Furthermore, we discuss the nature of the counterfactual Trojan horse attack and the strategy to successfully deal with it. Our results indicate that additional resources may be required for the protection against such an attack.

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Analysis of Trojan-Horse Attack against Untrusted Source

家涛 于

飞速发展的信息时代对信息安全保护提出了更高的要求，近年来基于量子物理属性的量子密码因其安全高效的优点而受到广泛关注。然而实际量子密钥分发系统往往达不到理想状态，这给实际通信系统带来很多安全性问题。本文首先介绍了基于量子纠缠的Ekert91量子密钥分发协议的原理和基本流程，在此基础上，借鉴基于极化单光子量子密钥分发协议中的特洛伊木马攻击思想，设计了针对纠缠协议的量子黑客攻击方案，同时对攻击思想、攻击原理、攻击步骤以及攻击效果进行了详细的分析。通过验证分析，所提攻击方案针对构成安全密钥的EPR光子对总量的30%进行测量，窃听者可以获得29.25%的安全密钥且只引入0.75%的误码率，具有重要的理论意义和现实可行性。 The rapid development of information age puts forward higher requirements on information se-curity protection. In recent years, quantum cryptography based on the theory of quantum physics gets more and more attention because of its reliability and high efficiency. However, the practical quantum key distribution system often cannot achieve the ideal state, which causes many security problems to the practical communication system. Firstly, this paper introduces the Ekert91 quantum key distribution (QKD) protocol based on quantum entanglement. Then, we propose a partial Trojan-horse attack scheme against this protocol and analyze the theory, process and the effect of the attack. The scheme measures thirty percent of EPR photon pairs used in the formation of security keys, the eavesdropper can obtain twenty-nine point two-five percent of security keys and only causes zero point seven-five percent error rate. The scheme possesses important theoretical significance and realistic feasibility.

Computer Science and Application•Jan 1, 2018•1 citation
Trojan horse attacking strategy on quantum cryptography is investigated. First, the fragility of the quantum cryptographic algorithm employing EPR (Einstein-Podosky-Rosen) pairs as a key against the Trojan horse attacking strategy is analyzed. To prevent the Trojan horse attacking, an improved scheme which makes use of the non-orthogonal entangled states is proposed. This scheme is robust to the Trojan horse attacking, without reducing the security on other kinds of attacking strategies.
Realistic experimental apparatus of quantum cryptography are imperfect, which may be utilized by a potential eavesdropper to eavesdrop on the communication. We show that quantum communication may be improved with quantum teleportation and entanglement swapping, which is robustly secure against the most general Trojan horse attacks. Our scheme is not an improvement of the communication apparatus, but the improvement of quantum communication protocol itself. We show that our modified schemes may be implemented with current technology.
Trojan horse attack is a common eavesdropping strategy which can attack various quantum secure communication systems. Its basic idea is to send auxiliary photons into a legitimate communicator's apparatuses and steal information by analyzing the reflected photons. In this paper, we consider a different kind of Trojan horse attack, the so-called counterfactual Trojan horse attack, which has not been studied in detail so far. In such an attack, the eavesdropper may steal the secret information by ``ghost'' photons, which can spontaneously avoid being detected, even if the detector is an ideal one. We present the details and requirements of such an attack. We also illustrate our results by considering two protocols, the ping-pong protocol and the counterfactual quantum cryptography. Furthermore, we discuss the nature of the counterfactual Trojan horse attack and the strategy to successfully deal with it. Our results indicate that additional resources may be required for the protection against such an attack.
A quantum cryptographic communication protocol with entanglement state is proposed to distribute secret messages deterministically. In this scheme the messages are encoded in the particles of the Einstein-Podolsky-Rosen (EPR) pairs rotated random polarization angles by applying random and independent operations. Security analysis indicates that this scheme is secure against the present Trojan horse attack strategy and the impersonation attack strategy, and it can also ensure the security of the messages in a low noisy channel. Moreover, it has an advantage that communication can be launched by the sender just like an actual communication system.
Abstract Early security proofs of the keys in quantum cryptography systems were based on the assumption that the transmitting and receiving stations were completely isolated from the outside world—the eavesdropper. However, this condition cannot be implemented in practice, since quantum cryptography systems are open systems, in the sense that an eavesdropper can have indirect access, for example, through a fiber communication channel to critical equipment elements (phase modulators, intensity modulators, etc) using active sensing of the state of these elements—Trojan-horse attacks. A new Trojan-horse attack based on joint unambiguous measurements of reflected probing states from an intensity modulator and information states in a quantum communication channel is proposed. Estimates of attack parameters for a number of quantum key distribution protocols are given, when an attack leads to compromise of keys.
飞速发展的信息时代对信息安全保护提出了更高的要求，近年来基于量子物理属性的量子密码因其安全高效的优点而受到广泛关注。然而实际量子密钥分发系统往往达不到理想状态，这给实际通信系统带来很多安全性问题。本文首先介绍了基于量子纠缠的Ekert91量子密钥分发协议的原理和基本流程，在此基础上，借鉴基于极化单光子量子密钥分发协议中的特洛伊木马攻击思想，设计了针对纠缠协议的量子黑客攻击方案，同时对攻击思想、攻击原理、攻击步骤以及攻击效果进行了详细的分析。通过验证分析，所提攻击方案针对构成安全密钥的EPR光子对总量的30%进行测量，窃听者可以获得29.25%的安全密钥且只引入0.75%的误码率，具有重要的理论意义和现实可行性。 The rapid development of information age puts forward higher requirements on information se-curity protection. In recent years, quantum cryptography based on the theory of quantum physics gets more and more attention because of its reliability and high efficiency. However, the practical quantum key distribution system often cannot achieve the ideal state, which causes many security problems to the practical communication system. Firstly, this paper introduces the Ekert91 quantum key distribution (QKD) protocol based on quantum entanglement. Then, we propose a partial Trojan-horse attack scheme against this protocol and analyze the theory, process and the effect of the attack. The scheme measures thirty percent of EPR photon pairs used in the formation of security keys, the eavesdropper can obtain twenty-nine point two-five percent of security keys and only causes zero point seven-five percent error rate. The scheme possesses important theoretical significance and realistic feasibility.