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

Study of Quantum Cryptography with a Thorlabs Teaching Apparatus

Dana Lamberton

Published Jan 1, 2019• 0 citations
OpenAlex

Abstract

A pseudo-quantum system consisting of laser diodes, wave retarders, beamsplitters, and photodetectors was employed to study encryption of data through binary transmission. The Jones vectors for each optical element can be represented in matrix notation and operated on through linear algebra computation. The laser diodes emit polarized photon pulses which can be represented by 2 x 1 matrices which are treated as transmitted bits. Because of the inherent randomness of polarized photons through a beamsplitter any intermediate detection and subsequent transmission of bits by a third party can immediately be detected. In this study, a total error of 25% was calculated for a 20-bit key and 52-bit protocol when the transmitted signal was intercepted in agreement with theory.

Related papers

Experimental System for Quantum Cryptography Based on Two Nonorthogonal Photon Polarization States

Yong Zhang, Le Deng, Min Mao +1 more

Quantum cryptography allows the establishing of a highly confidential sequence of random bits between two parties who share no secret information in advance. Its security is guaranteed by the basic laws of quantum mechanics rather than mathematical difficulty. An experimental system based on a novel protocol for quantum cryptography using only two nonorthogonal photon polarization states is implemented. The photon sources are two semiconductor laser diodes operated at 680 nm, their light pulses which are heavily attenuated to far below one photon per pulse are employed to encode the key. Gated single photon detection technique is used to minimize the dark count effect of the photon multiplier tube. Key establishing rate of 40 b/s and error rate of 2.1% are obtained. Compared with other systems, our system has the simplest experimental setup.

Chinese Physics Letters•Apr 1, 1998•13 citations

Experimental Realization of Quantum Cryptography by Arduino

Harith A. Qaisi, Mohammed Falih AL-Gailani

This paper is concerned with the experimental realization of an Arduino-based quantum cryptography system, in which a setup of five laser diodes is constructed in the transmitter that randomly emits photons to encode information consisting of a sequence of "0" and "1" bits. The receiver contains five photoresistor sensors that detect the presence or absence of light as well as determine the intensity of the light. Laser light is used to securely transmit data, such as text or numbers, in this technology.

Iraqi Journal of Information & Communications Technology•Apr 30, 2023•0 citations

Heisenberg, Bell, and experimental quantum cryptography

John Rarity, P. C. M. Owens, P. R. Tapster

When single photons are used to code for individual bits, security can be guaranteed by exploiting Heisenberg's uncertainty principle. Binary information can be coded into two orthogonal states, such as polarization or relative phase (in an interferometer). To receive this information we require an analyzer able to discriminate between the two states in an error-free way. In a linear-polarization system a polarizing beam splitter is used with its axes aligned to the two possible polarization directions. However, using a polarizer at 45° to these directions will ensure a random output uncorrelated to the single-photon-coded bit stream. The principle of secure key sharing, or quantum cryptography, is that a random bit stream is encoded onto individual photons while randomly switching the coding basis between the 0° and 45° polarization bases (in general, any non-orthogonal measurement bases). The receiver also randomly switches between these basis, and information is shared only when a photon is received and the same basis is used for coding and for measurement. An initial experiment of this type was carried out by using faint pulses of polarized visible light over a 40-cm transmission distance.1

•May 8, 1994•0 citations

Advanced Quantum Communication Protocols

Paul G. Kwiat

We have realized the first demonstration of "relativistic" quantum cryptography, using both faint laser pulses and entangled photons. By incorporating an optical delay cavity, Bob is able to measure every photon from Alice in the correct basis, leading to enhanced key rates, as well as some security advantages. We have also implemented our proposal for a high-speed quantum random number generator, in which the arrival time of a detected photon is used to generate -8 random bits per photon. Our system produced cryptographically secure bits at over 4 Mbits/s, with a clear path toward even higher rates. In addition, we solved a number of technical problems to produce 99%-fidelity polarization-entangled pairs from a diode-laser pumped source. Extending our previous implementation of remote state preparation, we have incorporated hyperentanglement to successfully remotely prepare entangled states. Finally, we studied the use of hyperentangled photons as a resource for improved quantum dense coding. Although our experimental verification is still in progress, we identified the theoretically optimal configuration, and compared hyperentangled and multi-pair encoding.

•Dec 17, 2005•0 citations

Link-layer vulnerabilities of quantum cryptography

Stamatios V. Kartalopoulos

The last two decades have witnessed an exciting advanced research field that stems from non-classical atomic theory, quantum mechanics. This field promises an important applicability in secure data communications, known as quantum cryptography. Quantum cryptography takes advantage of the inherent random polarization state of single photons, which is not reproducible by a third party or an eavesdropper located between the source and the destination. Thus, when polarization states of photons are associated with binary logic an algorithm may intelligently developed according to which a cryptographic key is disseminated by the source terminal to the destination. This is a process known as quantum key distribution. However, as photons propagate in a non-linear medium such as fiber, their polarization state does not remain intact and thus the quantum key distribution and quantum cryptography becomes vulnerable to attacks. In this paper we consider the applicability of quantum cryptography in a pragmatic fiber-optic medium and in a popular communication network topology. We identify major weaknesses for each step of the quantum key distribution process, and also potential attacks to incapacitate quantum cryptography in fiber communications, so that better countermeasure strategies can be developed.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Sep 16, 2005•3 citations

An Autocompensating Quantum Key Distribution System Using Polarization Splitting of Light

Donald S. Bethune, W. P. Risk

Quantum cryptographic key distribution (QKD) systems1 transmit cryptographic key data encoded in the quantum states of individual optical photons with security of the data guaranteed by the fundamental quantum properties of light, rather than by computational complexity or barriers to interception. Beamsplitter attacks are avoided by using single photons, while attempts to read and replace the photons with copies are thwarted by randomly switching between two non-orthogonal bases for the photon states. This so-called 4-state protocol1 forces an eavesdropper trying to read-and-replace photons to induce errors at a minimum rate of about 25%, which can be readily detected by the parties exchanging the key data. Several groups have performed QKD experiments that demonstrate its feasibility2.

Optics and Photonics News•May 3, 1998•3 citations
A pseudo-quantum system consisting of laser diodes, wave retarders, beamsplitters, and photodetectors was employed to study encryption of data through binary transmission. The Jones vectors for each optical element can be represented in matrix notation and operated on through linear algebra computation. The laser diodes emit polarized photon pulses which can be represented by 2 x 1 matrices which are treated as transmitted bits. Because of the inherent randomness of polarized photons through a beamsplitter any intermediate detection and subsequent transmission of bits by a third party can immediately be detected. In this study, a total error of 25% was calculated for a 20-bit key and 52-bit protocol when the transmitted signal was intercepted in agreement with theory.
Quantum cryptography allows the establishing of a highly confidential sequence of random bits between two parties who share no secret information in advance. Its security is guaranteed by the basic laws of quantum mechanics rather than mathematical difficulty. An experimental system based on a novel protocol for quantum cryptography using only two nonorthogonal photon polarization states is implemented. The photon sources are two semiconductor laser diodes operated at 680 nm, their light pulses which are heavily attenuated to far below one photon per pulse are employed to encode the key. Gated single photon detection technique is used to minimize the dark count effect of the photon multiplier tube. Key establishing rate of 40 b/s and error rate of 2.1% are obtained. Compared with other systems, our system has the simplest experimental setup.
This paper is concerned with the experimental realization of an Arduino-based quantum cryptography system, in which a setup of five laser diodes is constructed in the transmitter that randomly emits photons to encode information consisting of a sequence of "0" and "1" bits. The receiver contains five photoresistor sensors that detect the presence or absence of light as well as determine the intensity of the light. Laser light is used to securely transmit data, such as text or numbers, in this technology.
When single photons are used to code for individual bits, security can be guaranteed by exploiting Heisenberg's uncertainty principle. Binary information can be coded into two orthogonal states, such as polarization or relative phase (in an interferometer). To receive this information we require an analyzer able to discriminate between the two states in an error-free way. In a linear-polarization system a polarizing beam splitter is used with its axes aligned to the two possible polarization directions. However, using a polarizer at 45° to these directions will ensure a random output uncorrelated to the single-photon-coded bit stream. The principle of secure key sharing, or quantum cryptography, is that a random bit stream is encoded onto individual photons while randomly switching the coding basis between the 0° and 45° polarization bases (in general, any non-orthogonal measurement bases). The receiver also randomly switches between these basis, and information is shared only when a photon is received and the same basis is used for coding and for measurement. An initial experiment of this type was carried out by using faint pulses of polarized visible light over a 40-cm transmission distance.1
We have realized the first demonstration of "relativistic" quantum cryptography, using both faint laser pulses and entangled photons. By incorporating an optical delay cavity, Bob is able to measure every photon from Alice in the correct basis, leading to enhanced key rates, as well as some security advantages. We have also implemented our proposal for a high-speed quantum random number generator, in which the arrival time of a detected photon is used to generate -8 random bits per photon. Our system produced cryptographically secure bits at over 4 Mbits/s, with a clear path toward even higher rates. In addition, we solved a number of technical problems to produce 99%-fidelity polarization-entangled pairs from a diode-laser pumped source. Extending our previous implementation of remote state preparation, we have incorporated hyperentanglement to successfully remotely prepare entangled states. Finally, we studied the use of hyperentangled photons as a resource for improved quantum dense coding. Although our experimental verification is still in progress, we identified the theoretically optimal configuration, and compared hyperentangled and multi-pair encoding.
The last two decades have witnessed an exciting advanced research field that stems from non-classical atomic theory, quantum mechanics. This field promises an important applicability in secure data communications, known as quantum cryptography. Quantum cryptography takes advantage of the inherent random polarization state of single photons, which is not reproducible by a third party or an eavesdropper located between the source and the destination. Thus, when polarization states of photons are associated with binary logic an algorithm may intelligently developed according to which a cryptographic key is disseminated by the source terminal to the destination. This is a process known as quantum key distribution. However, as photons propagate in a non-linear medium such as fiber, their polarization state does not remain intact and thus the quantum key distribution and quantum cryptography becomes vulnerable to attacks. In this paper we consider the applicability of quantum cryptography in a pragmatic fiber-optic medium and in a popular communication network topology. We identify major weaknesses for each step of the quantum key distribution process, and also potential attacks to incapacitate quantum cryptography in fiber communications, so that better countermeasure strategies can be developed.
Quantum cryptographic key distribution (QKD) systems1 transmit cryptographic key data encoded in the quantum states of individual optical photons with security of the data guaranteed by the fundamental quantum properties of light, rather than by computational complexity or barriers to interception. Beamsplitter attacks are avoided by using single photons, while attempts to read and replace the photons with copies are thwarted by randomly switching between two non-orthogonal bases for the photon states. This so-called 4-state protocol1 forces an eavesdropper trying to read-and-replace photons to induce errors at a minimum rate of about 25%, which can be readily detected by the parties exchanging the key data. Several groups have performed QKD experiments that demonstrate its feasibility2.