Numerical finite-key analysis of quantum key distribution

AbstractQuantum key distribution (QKD) allows for secure communications safe against attacks by quantum computers. QKD protocols are performed by sending a sizeable, but finite, number of quantum signals between the distant parties involved. Many QKD experiments, however, predict their achievable key rates using asymptotic formulas, which assume the transmission of an infinite number of signals, partly because QKD proofs with finite transmissions (and finite-key lengths) can be difficult. Here we develop a robust numerical approach for calculating the key rates for QKD protocols in the finite-key regime in terms of two semi-definite programs (SDPs). The first uses the relation between conditional smooth min-entropy and quantum relative entropy through the quantum asymptotic equipartition property, and the second uses the relation between the smooth min-entropy and quantum fidelity. The numerical programs are formulated under the assumption of collective attacks from the eavesdropper and can be promoted to withstand coherent attacks using the postselection technique. We then solve these SDPs using convex optimization solvers and obtain numerical calculations of finite-key rates for several protocols difficult to analyze analytically, such as BB84 with unequal detector efficiencies, B92, and twin-field QKD. Our numerical approach democratizes the composable security proofs for QKD protocols where the derived keys can be used as an input to another cryptosystem.

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Quantum cryptography

Quantum Information ◽

10.1093/oso/9780198527626.003.0006 ◽

2009 ◽

Author(s):

Stephen Barnett

Keyword(s):

Quantum Information ◽

Quantum Cryptography ◽

Quantum Key Distribution ◽

Communication Systems ◽

Information Technologies ◽

Key Distribution ◽

Julius Caesar ◽

Secure Communications ◽

Quantum Communications ◽

History Of

The practical implementation of quantum information technologies requires, for the most part, highly advanced and currently experimental procedures. One exception is quantum cryptography, or quantum key distribution, which has been successfully demonstrated in many laboratories and has reached an advanced level of development. It will probably become the first commercial application of quantum information. In quantum key distribution, Alice and Bob exploit a quantum channel to create a secret shared key comprising a random string of binary digits. This key can then be used to protect a subsequent communication between them. The principal idea is that the secrecy of the key distribution is ensured by the laws of quantum physics. Proving security for practical communication systems is a challenging problem and requires techniques that are beyond the scope of this book. At a fundamental level, however, the ideas are simple and may readily be understood with the knowledge we have already acquired. Quantum cryptography is the latest idea in the long history of secure (and not so secure) communications and, if it is to develop, it will have to compete with existing technologies. For this reason we begin with a brief survey of the history and current state of the art in secure communications before turning to the possibilities offered by quantum communications. The history of cryptography is a long and fascinating one. As a consequence of the success or, more spectacularly, the failure of ciphers, wars have been fought, battles decided, kingdoms won, and heads lost. In the information age, ciphers and cryptosystems have become part of everyday life; we use them to protect our computers, to shop over the Internet, and to access our money via an ATM (automated teller machine). One of the oldest and simplest of all ciphers is the transposition or Caesarean cipher (attributed to Julius Caesar), in which the letters are shifted by a known (and secret) number of places in the alphabet. If the shift is 1, for example, then A is enciphered as B, B→C, · · ·, Y→Z, Z→A. A shift of five places leads us to make the replacements A→F, B→G, · · ·, Y→D, Z→E.

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Efficient and universal quantum key distribution based on chaos and middleware

International Journal of Modern Physics B ◽

10.1142/s0217979216502647 ◽

2017 ◽

Vol 31 (02) ◽

pp. 1650264 ◽

Cited By ~ 6

Author(s):

Dong Jiang ◽

Yuanyuan Chen ◽

Xuemei Gu ◽

Ling Xie ◽

Lijun Chen

Keyword(s):

Quantum Key Distribution ◽

High Speed ◽

Key Distribution ◽

Secure Communications ◽

Bit Rate ◽

Chaotic Cryptography ◽

Secret Keys ◽

Middleware Technology ◽

Universal Quantum ◽

The Many

Quantum key distribution (QKD) promises unconditionally secure communications, however, the low bit rate of QKD cannot meet the requirements of high-speed applications. Despite the many solutions that have been proposed in recent years, they are neither efficient to generate the secret keys nor compatible with other QKD systems. This paper, based on chaotic cryptography and middleware technology, proposes an efficient and universal QKD protocol that can be directly deployed on top of any existing QKD system without modifying the underlying QKD protocol and optical platform. It initially takes the bit string generated by the QKD system as input, periodically updates the chaotic system, and efficiently outputs the bit sequences. Theoretical analysis and simulation results demonstrate that our protocol can efficiently increase the bit rate of the QKD system as well as securely generate bit sequences with perfect statistical properties. Compared with the existing methods, our protocol is more efficient and universal, it can be rapidly deployed on the QKD system to increase the bit rate when the QKD system becomes the bottleneck of its communication system.

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An Overview of Quantum Key Distribution Protocols

Information Technology and Management Science ◽

10.7250/itms-2018-0005 ◽

2018 ◽

Vol 21 ◽

pp. 37-44 ◽

Cited By ~ 1

Author(s):

Anastasija Trizna ◽

Andris Ozols

Keyword(s):

Quantum Key Distribution ◽

Quantum Physics ◽

Key Distribution ◽

Quantum Computers ◽

Rapid Progress ◽

Close Attention ◽

Potential Threat ◽

Classical Systems ◽

Mathematical Problems ◽

System Improvement

Quantum key distribution (QKD) is the objects of close attention and rapid progress due to the fact that once first quantum computers are available – classical cryptography systems will become partially or completely insecure. The potential threat to today’s information security cannot be neglected, and efficient quantum computing algorithms already exist. Quantum cryptography brings a completely new level of security and is based on quantum physics principles, comparing with the classical systems that rely on hard mathematical problems. The aim of the article is to overview QKD and the most conspicuous and prominent QKD protocols, their workflow and security basement. The article covers 17 QKD protocols and each introduces novel ideas for further QKD system improvement.

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Numerical approach for unstructured quantum key distribution

Nature Communications ◽

10.1038/ncomms11712 ◽

2016 ◽

Vol 7 (1) ◽

Cited By ~ 40

Author(s):

Patrick J. Coles ◽

Eric M. Metodiev ◽

Norbert Lütkenhaus

Keyword(s):

Quantum Key Distribution ◽

Key Distribution ◽

Numerical Approach

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High-dimensional entanglement-enabled holography for quantum encryption

10.21203/rs.3.rs-658825/v1 ◽

2021 ◽

Author(s):

Ling-Jun Kong ◽

Furong Zhang ◽

Jingfeng Zhang ◽

Yifan Sun ◽

Xiangdong Zhang

Keyword(s):

Information Security ◽

Quantum Cryptography ◽

Quantum Key Distribution ◽

Quantum Algorithms ◽

Key Distribution ◽

High Dimensional ◽

Entangled State ◽

Quantum Computers ◽

Transmission Of Information ◽

Quantum Encryption

Abstract Cryptography plays an important role in information security, which is widely applied in the various fields of society. Quantum cryptography has shown its great advantages in information security compared with the classical one. Two major directions of quantum cryptography are quantum key distribution (QKD) and quantum encryption, with the former focusing on secure key distribution and the latter focusing on encryption using quantum algorithms. In contrast to the well accepted success of the QKD, the development of quantum encryption is rather limited because of the difficulties of building up algorithms and the constructing the practical quantum computers. Here we propose a new scheme of quantum encryption based on high-dimensional entanglement holography. Firstly, we experimentally realize the quantum holography based on the high-dimensional orbital angular momentum (OAM) entanglement. Then, OAM-selective holographic scheme for quantum encryption is proposed and demonstrated. Our results show that introducing quantum entangled state into OAM holography makes the OAM holography possess infinite information channels and the transmission of information be absolute security in principle. Furthermore, decryption in the presence of strong noise is achieved. Our work opens up a new way to realize quantum information security.

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Demonstrating BB84 Quantum Key Distribution in the Physical Layer of an Optical Fiber Based System

Infocommunications journal ◽

10.36244/icj.2021.3.5 ◽

2021 ◽

Vol 13 (2) ◽

pp. 45-55

Author(s):

Márton Czermann ◽

Péter Trócsányi ◽

Zsolt Kis ◽

Benedek Kovács ◽

László Bacsárdi

Keyword(s):

Quantum Key Distribution ◽

Quantum Physics ◽

Quantum Algorithm ◽

Key Distribution ◽

Public Key Cryptography ◽

Practical Significance ◽

Quantum Computers ◽

Symmetric Key ◽

Symmetric Key Cryptography ◽

Shor’S Quantum Algorithm

Nowadays, widely spread encryption methods (e.g., RSA) and protocols enabling digital signatures (e.g., DSA, ECDSA) are an integral part of our life. Although recently developed quantum computers have low processing capacity, huge dimensions and lack of interoperability, we must underline their practical significance – applying Peter Shor’s quantum algorithm (which makes it possible to factorize integers in polynomial time) public key cryptography is set to become breakable. As an answer, symmetric key cryptography proves to be secure against quantum based attacks and with it quantum key distribution (QKD) is going through vast development and growing to be a hot topic in data security. This is due to such methods securely generating symmetric keys by protocols relying on laws of quantum physics.

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