• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.1-5
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• 2016

The continuous variable quantum key distribution has been considered to have practical solution to provide high key rate. This paper explains the difference between DV-QKD and CV-QKD schemes. It describes CV-QKD as a theory that satisfies the uncertainty principle using continuous variable and homodyne detector. We shows varying length of secret key in QKD systems and amount of the exposed information to amplify privacy.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.5
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• pp.771-780
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• 2020

QKD(Quantum Key Distribution) is one of the protocols that can make two distant parties safely share secure keys against the threat of quantum computer. Generally, cryptographic applications which are connected to the QKD device have fixed roles as a transmitter and a receiver due to the race condition and complexity of implementation. Because the conventional QKD system is mainly applied to the link encryptor, there are no problems even if the roles of the cryptographic devices are fixed. We propose a new scheme of QKD system and protocol that is easy to extend to the QKD network by eliminating quantum key dependency between cryptographic device and QKD node. The secure keys which are generated by the TRNG(True Random Number Generator) are provided to the cryptographic applications instead of quantum keys. We design an architecture to transmit safely the secure keys using the inbound and outbound quantum keys which are shared between two nodes. In this scheme, since the dependency of shared quantum keys between two QKD nodes is eliminated, all cryptographic applicatons can be a master or a slave depending on who initiates the cryptographic communications.

• Information and Communications Magazine
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• v.31 no.9
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• pp.70-76
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• 2014

절대 보안성을 제공하는 양자 키 분배 (quantum key distribution, QKD)는 양자 역학을 이용한 정보통신 응용 중 가장 현실적으로 유망한 분야이다. BB84는 가장 널리 알려진 양자 암호키 분배 프로토콜로써, 4개의 양자 상태를 사용한다. 그 이후, 6개의 양자 상태를 사용하는 six-state 프로토콜이 제안되었으며, 이는 기 제안된 BB84프로토콜 대비 더 높은 보안성을 보이는 것으로 알려져 있다. 또한 QKD의 암호키 전송률 및 보안성 증가를 위해 이중 큐빗 QKD 프로토콜이 제안되었다. 이중 큐빗은 하나의 광자에 편광, 위상, 그리고 주파수 등의 서로 다른 두 개의 변조를 하는 것이다. 이중 큐빗 QKD 프로토콜은 16개의 양자 상태를 사용하며, 심볼 오류율 (Symbol Error Rate, SER)관점에서 앞서 언급한 두 개의 프로토콜 보다 더 높은 보안성을 보장할 수 있다. 본고에서는 앞서 언급한 총 3종류의 QKD 프로토콜의 보안성을 분석하고 비교함으로써 양자 상태 증가에 따른 QKD보안성을 성능을 살펴본다.

• Electronics and Telecommunications Trends
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• v.33 no.6
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• pp.94-106
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• 2018

A quantum key distribution (QKD) provides in principle an unconditional secure communication unlike the standard public key cryptography depending on the computational complexity. In particular, free-space QKD can give a secure solution even without a fiber-based infrastructure. In this paper, we investigate an overview of recent research trends in the free-space QKD system, including satellite and handheld moving platforms. In addition, we show the key components for a free-space QKD system such as the integrated components, single photon detectors, and quantum random number generator. We discuss the technical challenges and progress toward a future free- space QKD system and components.

• Journal of Information Science Theory and Practice
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• v.10 no.spc
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• pp.123-134
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• 2022

Existing network cryptography systems are threatened by recent developments in quantum computing. For example, the Shor algorithm, which can be run on a quantum computer, is capable of overriding public key-based network cryptography systems in a short time. Therefore, research on new cryptography systems is actively being conducted. The most powerful cryptography systems are quantum key distribution (QKD) and post quantum cryptograph (PQC) systems; in this study, a network based on both QKD and PQC is proposed, along with a quantum key management system (QKMS) and a Q-controller to efficiently operate the network. The proposed quantum cryptography communication network uses QKD as its backbone, and replaces QKD with PQC at the user end to overcome the shortcomings of QKD. This paper presents the functional requirements of QKMS and Q-Controller, which can be utilized to perform efficient network resource management.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.7-12
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• 2014

Quantum cryptography is one of the most feasible fields using quantum mechanics. Therefore, quantum cryptography has consistently been researched, and a variety of cryptographic exchange method has been developed, such as BB84, etc. This paper explains a basic concept of quantum communications and quantum key distribution systems using quantum mechanics. Also, it introduces a reason of the development of quantum cryptography and attack scenarios which threaten the security of QKD. Finally, the experiment of this paper simulates quantum key attack by estimating qubit phases through a modeled quantum channel, and discusses needs of post-processing methods for overcoming eavesdropping.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.152-156
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• 2017

This paper introduces the concept of random security amplification to amplify security in a quantum key distribution system. It seems to provide security amplification using the relationship between quantum error correction and security. In addition;we show that random security amplification in terms of security amplification offers better security than using existing universal hash function. We explain how the universal hash function enhances security using the BB84 protocol, which is a typical example of QKD. Finally, the proposed random security amplification and the conventional scheme compare the security according to the key generation rate in the quantum QKD.

• Review of KIISC
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• v.32 no.4
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• pp.99-107
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• 2022

본 논문에서는 표준화 기구에서 개발되었거나 아직 개발 중인, 양자 컴퓨팅에 의한 공격에 대해 안전한 양자 내성 보안체계로의 전환을 위해 양자 키 분배 (Quantum Key Distribution - QKD) 기술을 암호키 교환에 활용하는 다양한 하이브리드 접근 방식 들을 살펴보았다. 이러한 방법들은 두 가지 이상의 서로 다른 키 교환 방법을 결합하는 '키 교환을 위한 하이브리드 접근 방식'들을 의미한다. 양자 키 분배(QKD) 네트워크에서 생성하는 대칭 키를 활용하여 다른 방식으로 생성된 암호키와의 다양한 방식의 결합을 통한 하이브리드 접근 방식의 호환성에 대해서 살펴보았고, 아울러 다양한 네트워크 계층의 보안 통신 프로토콜과 함께 QKD를 함께 사용할 수 있도록 하는 표준들을 함께 분석하였으며, 이러한 표준들에서 추가적으로 개발이 필요한 영역들을 함께 살펴보았다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.4
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• pp.479-488
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• 2016

For a secure communication system, it is necessary to use secure cryptographic algorithms and keys. Modern cryptographic system generates high entropy encryption key through standard key derivation functions. Using recent progress in quantum key distribution(QKD) based on quantum physics, it is expected that we can enhance the security of modern cryptosystem. In this respect, the study on the dual key agreement is required, which combines quantum and modern cryptography. In this paper, we propose two key derivation functions using dual key agreement based on QKD and RSA cryptographic system. Furthermore, we demonstrate several simulations that estimate entropy of derived key so as to support the design rationale of our key derivation functions.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.38-42
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• 2017

This paper introduces the concept of a dual hash function to amplify security in a quantum key distribution system. We show the use of the relationship between quantum error correction and security to provide security amplification. Also, in terms of security amplification, the approach shows that phase error correction offers better security. We describe the process of enhancing security using the universal hash function using the BB84 protocol, which is a typical example of QKD. Finally, the deterministic universal hash function induces the security to be evaluated in the quantum Pauli channel without depending on the length of the message.