Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:quant-ph/0106046 · Journal of Experimental and Theoretical Physics Letters

The role of causality in ensuring the ultimate security of relativistic quantum cryptography

S. N. Molotkov, S. S. Nazin

Published Jun 1, 2001• 1 citation
arXivHTMLPDF

Abstract

One of the central points of quantum information theory is the problem of ultimate security of quantum cryptography; i.e., the security that is due only to the fundamental laws of nature rather than to technical restrictions. It is shown that a relativistic quantum cryptosystem proposed in this paper is ultimately secure against any eavesdropping attempts. The application of relativistic causality makes it possible to simply prove the security of the cryptosystem. Moreover, because the scheme does not involve collective measurements and quantum codes, it can be experimentally implemented even at the current level of optical fiber technologies.

DOI
10.1134/1.1397755

Related papers

Relativistic quantum cryptography

S. N. Molotkov, S. S. Nazin

The problem of unconditional security of quantum cryptography (i.e. the security which is guaranteed by the fundamental laws of nature rather than by technical limitations) is one of the central points in quantum information theory. We propose a relativistic quantum cryptosystem and prove its unconditional security against any eavesdropping attempts. Relativistitic causality arguments allow to demonstrate the security of the system in a simple way. Since the proposed protocol does not empoly collective measurements and quantum codes, the cryptosystem can be experimentally realized with the present state-of-art in fiber optics technologies. The proposed cryptosystem employs only the individual measurements and classical codes and, in addition, the key distribution problem allows to postpone the choice of the state encoding scheme until after the states are already received instead of choosing it before sending the states into the communication channel (i.e. to employ a sort of "antedate" coding).

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jul 23, 2003•0 citations

Free-space quantum cryptography using multiphoton states

S. N. Molotkov

Whereas quantum cryptography ensures security by virtue of complete indistinguishability of nonorthogonal quantum states attenuation in quantum communication channels and unavailability of single-photon sources present major problems. In view of these difficulties the security of quantum cryptography can change from unconditional to conditional. Since the restrictions imposed by nonrelativistic quantum mechanics and used to formulate key distribution protocols are largely exhausted new principles are required. The fundamental relativistic causality principle in quantum cryptography can be used to propose a new approach to ensuring unconditional security of quantum cryptosystems that eliminates the aforementioned difficulties. Quantum cryptosystems of this kind should obviously be called relativistic. It is shown that relativistic quantum cryptosystems remain unconditionally secure: first attenuation in a quantum communication channel can only reduce the key generation rate but not the security of the key second the source may not generate pure single-photon states and a nonzero single-photon probability will suffice. The scheme remains secure even if the contribution of a single-photon component is arbitrarily small. This formally implies that a state may be characterized by an arbitrarily large mean photon number. The single-photon probability affects only the key generation rate but not security.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jun 1, 2005•0 citations

Free-space quantum cryptography using multiphoton states: Secure key distribution to satellites

S. N. Molotkov

Whereas quantum cryptography ensures security by virtue of complete indistinguishability of nonorthogonal quantum states, attenuation in quantum communication channels and the unavailability of single-photon sources present major problems. In view of these difficulties, the security of quantum cryptography can change from unconditional to conditional. Since the restrictions imposed by nonrelativistic quantum mechanics and used to formulate key distribution protocols have been largely exhausted, new principles are required. The fundamental relativistic causality principle in quantum cryptography can be used to propose a new approach to ensuring unconditional security of quantum cryptosystems that eliminates the aforementioned difficulties. Quantum cryptosystems of this kind should obviously be called relativistic. It is shown that relativistic quantum cryptosystems remain unconditionally secure: first, attenuation in a quantum communication channel can only reduce the key generation rate, but not the security of the key; second, the source may not generate pure single-photon states, and a nonzero single-photon probability will suffice. The scheme remains secure even if the contribution of a single-photon component is arbitrarily small. This formally implies that a state may be characterized by an arbitrarily large mean photon number. The single-photon probability affects only the key generation rate, but not security.

Journal of Experimental and Theoretical Physics•Oct 1, 2004•0 citations

Quantum Cryptography: Realizing next generation information security

Payal P. Kilor

Quantum cryptography is a technology that ensures ultimate security. Compared to current cryptography that could be defeated by by the development of an ultra high-speed computer, quantum cryptography ensures secure communication because it is based on the fundamental physical laws. It is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. Quantum cryptography is a new method for secret communications offering the ultimate security assurance of the inviolability of a Law of Nature. The quantum cryptography relies relies on two important elements of quantum mechanics-the Heisenberg Uncertainty principle and the principle of photon polarization. This research paper concentrates on the principle of quantum cryptography, and how this technology contributes to the network security. This paper outlines the real world application implementation of this technology and the future direction in which quantum cryptography accelerates.

•Jan 1, 2014•18 citations

A simple proof of unconditional security of relativistic quantum cryptography

S. N. Molotkov, S. S. Nazin

A simple proof of the unconditional security of a relativistic quantum cryptosystem based on orthogonal states is given. Limitations imposed by the special relativity theory allow the proof to be markedly simplified as compared to the case of nonrelativistic cryptosystems based on nonorthogonal states. An important point in the proposed protocol is a space-time structure of the quantum states, which is ignored in the non-relativistic protocols using only the properties of the space of states of the information carriers. As a consequence, the simplification is related to the inefficacy of using the collective measurements against an eavesdropper, the allowance for which is an especially difficult task in the nonrelativistic case.

arXiv:quant-ph/0008008•Journal of Experimental and Theoretical Physics•May 1, 2001•2 citations

Simple delay scheme for quantum cryptography based on a Mach-Zehnder optic fiber interferometer

S. N. Molotkov

A simple experimental scheme is proposed for a relativistic quantum cryptosystem based on a Mach-Zehnder optic fiber interferometer. In this scheme, quantum mechanical laws, along with the restrictions imposed by the Special Relativity, ensure the detection of any eavesdropping attempt.

Journal of Experimental and Theoretical Physics Letters•Aug 1, 2003•0 citations
One of the central points of quantum information theory is the problem of ultimate security of quantum cryptography; i.e., the security that is due only to the fundamental laws of nature rather than to technical restrictions. It is shown that a relativistic quantum cryptosystem proposed in this paper is ultimately secure against any eavesdropping attempts. The application of relativistic causality makes it possible to simply prove the security of the cryptosystem. Moreover, because the scheme does not involve collective measurements and quantum codes, it can be experimentally implemented even at the current level of optical fiber technologies.
The problem of unconditional security of quantum cryptography (i.e. the security which is guaranteed by the fundamental laws of nature rather than by technical limitations) is one of the central points in quantum information theory. We propose a relativistic quantum cryptosystem and prove its unconditional security against any eavesdropping attempts. Relativistitic causality arguments allow to demonstrate the security of the system in a simple way. Since the proposed protocol does not empoly collective measurements and quantum codes, the cryptosystem can be experimentally realized with the present state-of-art in fiber optics technologies. The proposed cryptosystem employs only the individual measurements and classical codes and, in addition, the key distribution problem allows to postpone the choice of the state encoding scheme until after the states are already received instead of choosing it before sending the states into the communication channel (i.e. to employ a sort of "antedate" coding).
Whereas quantum cryptography ensures security by virtue of complete indistinguishability of nonorthogonal quantum states attenuation in quantum communication channels and unavailability of single-photon sources present major problems. In view of these difficulties the security of quantum cryptography can change from unconditional to conditional. Since the restrictions imposed by nonrelativistic quantum mechanics and used to formulate key distribution protocols are largely exhausted new principles are required. The fundamental relativistic causality principle in quantum cryptography can be used to propose a new approach to ensuring unconditional security of quantum cryptosystems that eliminates the aforementioned difficulties. Quantum cryptosystems of this kind should obviously be called relativistic. It is shown that relativistic quantum cryptosystems remain unconditionally secure: first attenuation in a quantum communication channel can only reduce the key generation rate but not the security of the key second the source may not generate pure single-photon states and a nonzero single-photon probability will suffice. The scheme remains secure even if the contribution of a single-photon component is arbitrarily small. This formally implies that a state may be characterized by an arbitrarily large mean photon number. The single-photon probability affects only the key generation rate but not security.
Whereas quantum cryptography ensures security by virtue of complete indistinguishability of nonorthogonal quantum states, attenuation in quantum communication channels and the unavailability of single-photon sources present major problems. In view of these difficulties, the security of quantum cryptography can change from unconditional to conditional. Since the restrictions imposed by nonrelativistic quantum mechanics and used to formulate key distribution protocols have been largely exhausted, new principles are required. The fundamental relativistic causality principle in quantum cryptography can be used to propose a new approach to ensuring unconditional security of quantum cryptosystems that eliminates the aforementioned difficulties. Quantum cryptosystems of this kind should obviously be called relativistic. It is shown that relativistic quantum cryptosystems remain unconditionally secure: first, attenuation in a quantum communication channel can only reduce the key generation rate, but not the security of the key; second, the source may not generate pure single-photon states, and a nonzero single-photon probability will suffice. The scheme remains secure even if the contribution of a single-photon component is arbitrarily small. This formally implies that a state may be characterized by an arbitrarily large mean photon number. The single-photon probability affects only the key generation rate, but not security.
Quantum cryptography is a technology that ensures ultimate security. Compared to current cryptography that could be defeated by by the development of an ultra high-speed computer, quantum cryptography ensures secure communication because it is based on the fundamental physical laws. It is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. Quantum cryptography is a new method for secret communications offering the ultimate security assurance of the inviolability of a Law of Nature. The quantum cryptography relies relies on two important elements of quantum mechanics-the Heisenberg Uncertainty principle and the principle of photon polarization. This research paper concentrates on the principle of quantum cryptography, and how this technology contributes to the network security. This paper outlines the real world application implementation of this technology and the future direction in which quantum cryptography accelerates.
A simple proof of the unconditional security of a relativistic quantum cryptosystem based on orthogonal states is given. Limitations imposed by the special relativity theory allow the proof to be markedly simplified as compared to the case of nonrelativistic cryptosystems based on nonorthogonal states. An important point in the proposed protocol is a space-time structure of the quantum states, which is ignored in the non-relativistic protocols using only the properties of the space of states of the information carriers. As a consequence, the simplification is related to the inefficacy of using the collective measurements against an eavesdropper, the allowance for which is an especially difficult task in the nonrelativistic case.