scholarly journals Unconditional Security by the Laws of Classical Physics

2013 ◽  
Vol 20 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Robert Mingesz ◽  
Laszlo Bela Kish ◽  
Zoltan Gingl ◽  
Claes-Göran Granqvist ◽  
He Wen ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
Key Exchange ◽  
Johnson Noise ◽  
Ongoing Debate ◽  
Classical Physics ◽  
Information Theoretic ◽  
Information Theoretic Security ◽  
Essential Questions ◽  
Security Levels

Abstract There is an ongoing debate about the fundamental security of existing quantum key exchange schemes. This debate indicates not only that there is a problem with security but also that the meanings of perfect, imperfect, conditional and unconditional (information theoretic) security in physically secure key exchange schemes are often misunderstood. It has been shown recently that the use of two pairs of resistors with enhanced Johnsonnoise and a Kirchhoff-loop ‒ i.e., a Kirchhoff-Law-Johnson-Noise (KLJN) protocol ‒ for secure key distribution leads to information theoretic security levels superior to those of today’s quantum key distribution. This issue is becoming particularly timely because of the recent full cracks of practical quantum communicators, as shown in numerous peer-reviewed publications. The KLJN system is briefly surveyed here with discussions about the essential questions such as (i) perfect and imperfect security characteristics of the key distribution, and (ii) how these two types of securities can be unconditional (or information theoretical).

scholarly journals Device-independent quantum key distribution with random key basis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
René Schwonnek ◽  
Koon Tong Goh ◽  
Ignatius W. Primaatmaja ◽  
Ernest Y.-Z. Tan ◽  
Ramona Wolf ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Bell Inequality ◽  
Key Distribution ◽  
Theory And Practice ◽  
Information Theoretic ◽  
Information Theoretic Security ◽  
Experimental Parameters ◽  
Secret Keys ◽  
Simple Variant ◽  
First Time

AbstractDevice-independent quantum key distribution (DIQKD) is the art of using untrusted devices to distribute secret keys in an insecure network. It thus represents the ultimate form of cryptography, offering not only information-theoretic security against channel attacks, but also against attacks exploiting implementation loopholes. In recent years, much progress has been made towards realising the first DIQKD experiments, but current proposals are just out of reach of today’s loophole-free Bell experiments. Here, we significantly narrow the gap between the theory and practice of DIQKD with a simple variant of the original protocol based on the celebrated Clauser-Horne-Shimony-Holt (CHSH) Bell inequality. By using two randomly chosen key generating bases instead of one, we show that our protocol significantly improves over the original DIQKD protocol, enabling positive keys in the high noise regime for the first time. We also compute the finite-key security of the protocol for general attacks, showing that approximately 108–1010 measurement rounds are needed to achieve positive rates using state-of-the-art experimental parameters. Our proposed DIQKD protocol thus represents a highly promising path towards the first realisation of DIQKD in practice.

scholarly journals Physical-layer encryption on the public internet: A stochastic approach to the Kish-Sethuraman cipher

2014 ◽  
Vol 33 ◽  
pp. 1460361 ◽  
Author(s):  
Lachlan J. Gunn ◽  
James M. Chappell ◽  
Andrew Allison ◽  
Derek Abbott
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
Key Distribution ◽  
Stochastic Approach ◽  
Physical Layer ◽  
Information Theoretic ◽  
The Public ◽  
Information Theoretic Security ◽  
Transit Times ◽  
The One

While information-theoretic security is often associated with the one-time pad and quantum key distribution, noisy transport media leave room for classical techniques and even covert operation. Transit times across the public internet exhibit a degree of randomness, and cannot be determined noiselessly by an eavesdropper. We demonstrate the use of these measurements for information-theoretically secure communication over the public internet.

scholarly journals The attack strategy for a quantum key distribution protocol based on Bell’s theorem

2021 ◽  
Vol 2056 (1) ◽  
pp. 012011
Author(s):  
Chan Myae Hein ◽  
T F Kamalov
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
Bell’S Theorem ◽  
Bell's Theorem ◽  
Secret Key ◽  
Theoretical Concepts ◽  
Information Theoretic ◽  
Information Theoretic Security ◽  
Quantum Key Distribution Protocol ◽  
Attack Strategy

Abstract A new eavesdropping strategy is proposed for the Quantum Key Distribution (QKD) protocol. This scheme represents a new kind of intercept/resend strategy based on Bell’s theorem. Quantum key distribution (QKD) provides the foremost reliable form of secure key exchange, using only the input-output statistics of the devices to realize information-theoretic security. In this paper, we present an improved QKD protocol that can simultaneously distribute the quantum secret key. We are already using the QKD protocol with simulated results matched completely with the theoretical concepts.

scholarly journals Quantum key distribution with correlated sources

2020 ◽  
Vol 6 (37) ◽  
pp. eaaz4487 ◽  
Author(s):  
Margarida Pereira ◽  
Go Kato ◽  
Akihiro Mizutani ◽  
Marcos Curty ◽  
Kiyoshi Tamaki
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
The Other ◽  
Correlated Sources ◽  
Information Theoretic ◽  
Security Proofs ◽  
Information Theoretic Security ◽  
Special Cases ◽  
New Framework ◽  
General Method

In theory, quantum key distribution (QKD) offers information-theoretic security. In practice, however, it does not due to the discrepancies between the assumptions used in the security proofs and the behavior of the real apparatuses. Recent years have witnessed a tremendous effort to fill the gap, but the treatment of correlations among pulses has remained a major elusive problem. Here, we close this gap by introducing a simple yet general method to prove the security of QKD with arbitrarily long-range pulse correlations. Our method is compatible with those security proofs that accommodate all the other typical device imperfections, thus paving the way toward achieving implementation security in QKD with arbitrary flawed devices. Moreover, we introduce a new framework for security proofs, which we call the reference technique. This framework includes existing security proofs as special cases, and it can be widely applied to a number of QKD protocols.

Performance analysis of the “intelligent” Kirchhoff-Law-Johnson-Noise secure key exchange

2014 ◽  
Vol 33 ◽  
pp. 1460368
Author(s):  
Janusz Smulko
Keyword(s):  
Performance Analysis ◽  
Distribution System ◽  
Key Distribution ◽  
Key Exchange ◽  
Johnson Noise ◽  
Statistical Tools ◽  
Information Theoretic ◽  
The Wire ◽  
Averaging Time

The Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system provides a way of exchanging information theoretic secure keys by measuring the random voltage and current through the wire connecting two different resistors at Alice's and Bob's ends. Recently new advanced protocols for the KLJN method have been proposed with enhanced performance. In this paper we analyze the KLJN system and compare with “intelligent” KLJN (iKLJN) scheme. This task requires the determination of the applied resistors and the identification of the various superpositions of known and unknown noise components. Some statistical tools to determine how the duration of the bit exchange window (averaging time) influences the performance of secure bit exchange will be explored.

scholarly journals Comments on “A New Transient Attack on the Kish Key Distribution System”

2016 ◽  
Vol 23 (3) ◽  
pp. 321-331 ◽  
Author(s):  
Laszlo B. Kish ◽  
Claes G. Granqvist
Keyword(s):  
Distribution System ◽  
Key Distribution ◽  
Key Exchange ◽  
Security Measures ◽  
Johnson Noise ◽  
Exchange System ◽  
Classical Physics ◽  
The One

Abstract A recent IEEE Access Paper by Gunn, Allison and Abbott (GAA) proposed a new transient attack against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system. The attack is valid, but it is easy to build a defense for the KLJN system. Here we note that GAA’s paper contains several invalid statements regarding security measures and the continuity of functions in classical physics. These deficiencies are clarified in our present paper, wherein we also emphasize that a new version of the KLJN system is immune against all existing attacks, including the one by GAA.

Experimental study of the Kirchhoff-Law-Johnson-Noise secure key exchange

2014 ◽  
Vol 33 ◽  
pp. 1460365 ◽  
Author(s):  
Robert Mingesz
Keyword(s):  
Experimental Study ◽  
Distribution System ◽  
Communication Protocol ◽  
Experimental Tests ◽  
Key Distribution ◽  
Key Exchange ◽  
Theoretical Studies ◽  
Johnson Noise ◽  
Classical Physics ◽  
Dedicated Hardware

The Kirchhoff-Law-Johnson-Noise (KLJN) secure key distribution system provides a way of exchanging secure keys by using classical physics (electricity and thermodynamics). Several theoretical studies have addressed the performance and applicability of the communication protocol, and they have indicated that it is protected against all known types of attacks. However, until now, there have been very few real physical implementations and experimental tests of the protocol. With our work, we continue filling this gap. Details of implementing a KLJN based system are presented using a dedicated hardware and an off-the-shelf solution as well. Furthermore, the results of experimental tests and analysis of the performance will be presented.

Cryptanalysis of a Practical Quantum Key Distribution with Polarization-Entangled Photons

2005 ◽  
Vol 5 (3) ◽  
pp. 181-186
Author(s):  
Th. Beth ◽  
J. Muller-Quade ◽  
R. Steinwandt
Keyword(s):  
Quantum Cryptography ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Key Exchange ◽  
Authentication Scheme ◽  
Entangled Photons ◽  
Key Exchange Protocol

Recently, a quantum key exchange protocol has been described\cite{PFLM04}, which served as basis for securing an actual bank transaction by means of quantum cryptography \cite{ZVS04}. The authentication scheme used to this aim has been proposed by Peev et al. \cite{PML04}. Here we show, that this authentication is insecure in the sense that an attacker can provoke a situation where initiator and responder of a key exchange end up with different keys. Moreover, it may happen that an attacker can decrypt a part of the plaintext protected with the derived encryption key.

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