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

International Journal of Computer Applications

A Practical Quantum Cryptography Transmitter

Fouad AliYaseen

Published Feb 13, 2014• 0 citations
Publisher

Abstract

The extend success of any communication system essentially depends on the strength of the secrecy of transporting the information between the partners.The classical cryptography for the wired and wireless communication systems can not withstand against the challenges of new technologies.So, it is necessary to invent a new method to encrypt the information.The solution is quantum cryptography in communication system.The absolute security can be achieve with quantum cryptography protocol via building an effective hardware for satisfying the single-photon source must requirement by controlling the value of mean photon number.This was approximately achieved in this work by building a driving circuit that provide very short pulses, less than 10 ns for Laser Diode with output maximum power of 0.99 mW and wavelength 650 nm.These short pulses enable getting faint laser pulses that were further attenuated to reach mean photon number equal to 0.08 or less.

DOI
10.5120/15205-3607

Related papers

A Practical Quantum Cryptography Transmitter

Fouad Ali Yaseen

Computer center The extend success of any communication system essentially depends on the strength of the secrecy of transporting the information between the partners. The classical cryptography for the wired and wireless communication systems can not withstand against the challenges of new technologies. So, it is necessary to invent a new method to encrypt the information. The solution is quantum cryptography in communication system. The absolute security can be achieve with quantum cryptography protocol via building an effective hardware for satisfying the single-photon source must requirement by controlling the value of mean photon number. This was approximately achieved in this work by building a driving circuit that provide very short pulses, less than 10 ns for Laser Diode with output maximum power of 0.99 mW and wavelength 650 nm. These short pulses enable getting faint laser pulses that were further attenuated to reach mean photon number equal to 0.08 or less.

International Journal of Computer Applications•Feb 14, 2014•0 citations

Quantum communications

J. D. Franson

Quantum mechanics allows a number of communications protocols that would not be possible classically, including provably-secure messages (quantum cryptography), increased channel capacity, and the ability to transmit an unknown quantum state (quantum teleportation). This tutorial will provide an introductory description of what appear to be the most promising applications of quantum communications, including quantum cryptography and quantum repeaters. The most commonly-used methods for quantum cryptography will be described, including the advantages and disadvantages of each in practical applications. The maximum range of current quantum cryptography systems is limited by the fact that optical amplifiers would destroy the quantum coherence of single photons and cannot be used in these kinds of systems. One potential solution to this problem is the transmission of single photons in free space, which would allow a global system for quantum cryptography based on a network of satellites and ground stations. Free-space quantum cryptography systems of that kind have now been demonstrated over relatively short distances. The range of quantum cryptography systems in optical fibers can also be extended using quantum repeaters that make use of entanglement purification and quantum teleportation. These same techniques could also be used to implement a “quantum Internet” for the transmission of qubits from one quantum computer to another. The practical challenges that will have to be met in order to implement quantum repeaters and quantum teleportation over large distances will be discussed.

Optical Fiber Communication Conference•Jan 1, 2001•1 citation

Design and construction of a high speed quantum key distribution device

Stuart Holt

Quantum cryptography has been proven to be the only practical method for fast distribution of secret keys needed for encryption. It enables absolutely secure information transfer from one party to another and allows for the detection of an eavesdropper without sacrificing security. This project involved designing and building a quantum cryptography device. This device has applications in many fields, including internet security as well as military communications. The data are encoded on single photons, which are sent through free space over a distance of about 30 cm. The electronics, which control the device however, are equally suitable for operation with fibre optic cables. The device was designed to operate in dark conditions within a laboratory. Currently, no research group has demonstrated transmission speeds faster than 8 kb/s. The aim of this project was to achieve bit rates faster than 10 kb/s, while operating under strict economic constraints. Although quantum cryptography was not demonstrated in the laboratory due to problems with the detector, the emission end, which generates single photons of light with one of two different polarisations, was shown to work as it was designed. The current design has limited commercial future due to the dark conditions under which the communication must take place. The project however has demonstrated that quantum cryptography is getting closer to becoming a reality.

•Jan 1, 2001•0 citations

Single-photon devices in quantum cryptography

Wlodzimierz Nakwaski, Robert P. Sarzała, Michał Wasiak +2 more

Modern communication in absolute secrecy requires creation of new intrinsically secure quantum communication channels. It is particularly necessary during the first connection between two parties establishing then in assumed unconditional security the secret cryptographic key which is supposed to be used afterwards during normal information exchanging. This new emerging field of quantum information technology is based on a new type of light sources, in which numbers of emitted photons can be carefully controlled. Especially advantageous are sources of single photons emitted at strictly predetermined moments, so called single-photon devices. Then any possible eavesdropper activity will be followed by some unavoidable disturbance which alerts both communication parties to an event. In the present paper, the Purcell effect associated with enhancement of spontaneous emission coupled to a resonator is explained, methods used to produce streams of antibunched photons are given, mechanisms applied to control carrier injection into quantum dots are shown and some possible designs of single-photon devices are presented and described. These devices are based on taking advantage of both the Purcell effect and the atom-like energy spectrum of quantum dots.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 21, 2003•2 citations

Quantum Cryptography: From Theory to Practice

Xiongfeng Ma

Quantum cryptography or quantum key distribution (QKD) applies fundamental laws of quantum physics to guarantee secure communication. The security of quantum cryptography was proven in the last decade. Many security analyses are based on the assumption that QKD system components are idealized. In practice, inevitable device imperfections may compromise security unless these imperfections are well investigated.\n\nA highly attenuated laser pulse which gives a weak coherent state is widely used in QKD experiments. A weak coherent state has multi-photon components, which opens up a security loophole to the sophisticated eavesdropper. With a small adjustment of the hardware, we will prove that the decoy state method can close this loophole and substantially improve the QKD performance. We also propose a few practical decoy state protocols, study statistical fluctuations and perform experimental demonstrations. Moreover, we will apply the methods from entanglement distillation protocols based on two-way classical communication to improve the decoy state QKD performance. Furthermore, we study the decoy state methods for other single photon sources, such as triggering parametric down-conversion (PDC) source. Note that our work, decoy state protocol, has attracted a lot of scientific and media interest. The decoy state QKD becomes a standard technique for prepare-and-measure QKD schemes.\n\nAside from single-photon-based QKD schemes, there is another type of scheme based on entangled photon sources. A PDC source is commonly used as an entangled photon source. We propose a model and post-processing scheme for the entanglement-based QKD with a PDC source. Although the model is proposed to study the entanglement-based QKD, we emphasize that our generic model may also be useful for other non-QKD experiments involving a PDC source. By simulating a real PDC experiment, we show that the entanglement-based QKD can achieve longer maximal secure distance than the single-photon-based QKD schemes.\n\nWe propose a time-shift attack that exploits the efficiency mismatch of two single photon detectors in a QKD system. This eavesdropping strategy can be realized by current technology. We will also discuss counter measures against the attack and study the security of a QKD system with efficiency mismatch detectors.

•Feb 26, 2009•21 citations

Investigations on Long Wavelength Quantum Cryptography Systems

F. Gibson, Alexandru Hening, Mohamed Bourennane +4 more

Quantum cryptography is a technique for establishing a fundamentally secure key for cryptography using the encoding of the key on single photon states in such a way that an eavesdropper cannot acquire any information about the key without impairing detectable errors in the communication channel [1]. In the recent years there has been a remarkable progress in experimental implementations at 850 nm and 1300 nm wavelengths with secret key generation at kbits/s up to 48 km distance. However, for 1550 nm wavelength, where fiber losses are as smallest, progress has been hampered by the lack of good single photon detectors.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jan 1, 1998•0 citations
The extend success of any communication system essentially depends on the strength of the secrecy of transporting the information between the partners.The classical cryptography for the wired and wireless communication systems can not withstand against the challenges of new technologies.So, it is necessary to invent a new method to encrypt the information.The solution is quantum cryptography in communication system.The absolute security can be achieve with quantum cryptography protocol via building an effective hardware for satisfying the single-photon source must requirement by controlling the value of mean photon number.This was approximately achieved in this work by building a driving circuit that provide very short pulses, less than 10 ns for Laser Diode with output maximum power of 0.99 mW and wavelength 650 nm.These short pulses enable getting faint laser pulses that were further attenuated to reach mean photon number equal to 0.08 or less.
Computer center The extend success of any communication system essentially depends on the strength of the secrecy of transporting the information between the partners. The classical cryptography for the wired and wireless communication systems can not withstand against the challenges of new technologies. So, it is necessary to invent a new method to encrypt the information. The solution is quantum cryptography in communication system. The absolute security can be achieve with quantum cryptography protocol via building an effective hardware for satisfying the single-photon source must requirement by controlling the value of mean photon number. This was approximately achieved in this work by building a driving circuit that provide very short pulses, less than 10 ns for Laser Diode with output maximum power of 0.99 mW and wavelength 650 nm. These short pulses enable getting faint laser pulses that were further attenuated to reach mean photon number equal to 0.08 or less.
Quantum mechanics allows a number of communications protocols that would not be possible classically, including provably-secure messages (quantum cryptography), increased channel capacity, and the ability to transmit an unknown quantum state (quantum teleportation). This tutorial will provide an introductory description of what appear to be the most promising applications of quantum communications, including quantum cryptography and quantum repeaters. The most commonly-used methods for quantum cryptography will be described, including the advantages and disadvantages of each in practical applications. The maximum range of current quantum cryptography systems is limited by the fact that optical amplifiers would destroy the quantum coherence of single photons and cannot be used in these kinds of systems. One potential solution to this problem is the transmission of single photons in free space, which would allow a global system for quantum cryptography based on a network of satellites and ground stations. Free-space quantum cryptography systems of that kind have now been demonstrated over relatively short distances. The range of quantum cryptography systems in optical fibers can also be extended using quantum repeaters that make use of entanglement purification and quantum teleportation. These same techniques could also be used to implement a “quantum Internet” for the transmission of qubits from one quantum computer to another. The practical challenges that will have to be met in order to implement quantum repeaters and quantum teleportation over large distances will be discussed.
Quantum cryptography has been proven to be the only practical method for fast distribution of secret keys needed for encryption. It enables absolutely secure information transfer from one party to another and allows for the detection of an eavesdropper without sacrificing security. This project involved designing and building a quantum cryptography device. This device has applications in many fields, including internet security as well as military communications. The data are encoded on single photons, which are sent through free space over a distance of about 30 cm. The electronics, which control the device however, are equally suitable for operation with fibre optic cables. The device was designed to operate in dark conditions within a laboratory. Currently, no research group has demonstrated transmission speeds faster than 8 kb/s. The aim of this project was to achieve bit rates faster than 10 kb/s, while operating under strict economic constraints. Although quantum cryptography was not demonstrated in the laboratory due to problems with the detector, the emission end, which generates single photons of light with one of two different polarisations, was shown to work as it was designed. The current design has limited commercial future due to the dark conditions under which the communication must take place. The project however has demonstrated that quantum cryptography is getting closer to becoming a reality.
Modern communication in absolute secrecy requires creation of new intrinsically secure quantum communication channels. It is particularly necessary during the first connection between two parties establishing then in assumed unconditional security the secret cryptographic key which is supposed to be used afterwards during normal information exchanging. This new emerging field of quantum information technology is based on a new type of light sources, in which numbers of emitted photons can be carefully controlled. Especially advantageous are sources of single photons emitted at strictly predetermined moments, so called single-photon devices. Then any possible eavesdropper activity will be followed by some unavoidable disturbance which alerts both communication parties to an event. In the present paper, the Purcell effect associated with enhancement of spontaneous emission coupled to a resonator is explained, methods used to produce streams of antibunched photons are given, mechanisms applied to control carrier injection into quantum dots are shown and some possible designs of single-photon devices are presented and described. These devices are based on taking advantage of both the Purcell effect and the atom-like energy spectrum of quantum dots.
Quantum cryptography or quantum key distribution (QKD) applies fundamental laws of quantum physics to guarantee secure communication. The security of quantum cryptography was proven in the last decade. Many security analyses are based on the assumption that QKD system components are idealized. In practice, inevitable device imperfections may compromise security unless these imperfections are well investigated.\n\nA highly attenuated laser pulse which gives a weak coherent state is widely used in QKD experiments. A weak coherent state has multi-photon components, which opens up a security loophole to the sophisticated eavesdropper. With a small adjustment of the hardware, we will prove that the decoy state method can close this loophole and substantially improve the QKD performance. We also propose a few practical decoy state protocols, study statistical fluctuations and perform experimental demonstrations. Moreover, we will apply the methods from entanglement distillation protocols based on two-way classical communication to improve the decoy state QKD performance. Furthermore, we study the decoy state methods for other single photon sources, such as triggering parametric down-conversion (PDC) source. Note that our work, decoy state protocol, has attracted a lot of scientific and media interest. The decoy state QKD becomes a standard technique for prepare-and-measure QKD schemes.\n\nAside from single-photon-based QKD schemes, there is another type of scheme based on entangled photon sources. A PDC source is commonly used as an entangled photon source. We propose a model and post-processing scheme for the entanglement-based QKD with a PDC source. Although the model is proposed to study the entanglement-based QKD, we emphasize that our generic model may also be useful for other non-QKD experiments involving a PDC source. By simulating a real PDC experiment, we show that the entanglement-based QKD can achieve longer maximal secure distance than the single-photon-based QKD schemes.\n\nWe propose a time-shift attack that exploits the efficiency mismatch of two single photon detectors in a QKD system. This eavesdropping strategy can be realized by current technology. We will also discuss counter measures against the attack and study the security of a QKD system with efficiency mismatch detectors.
Quantum cryptography is a technique for establishing a fundamentally secure key for cryptography using the encoding of the key on single photon states in such a way that an eavesdropper cannot acquire any information about the key without impairing detectable errors in the communication channel [1]. In the recent years there has been a remarkable progress in experimental implementations at 850 nm and 1300 nm wavelengths with secret key generation at kbits/s up to 48 km distance. However, for 1550 nm wavelength, where fiber losses are as smallest, progress has been hampered by the lack of good single photon detectors.