Self-compensating GigaHertz-clocked Quantum Key Distribution

自补偿千兆赫时钟量子密钥分配

• 批准号: EP/E003729/1
• 负责人: Gerald Buller
• 金额: $ 39.14万
• 依托单位: Heriot-Watt University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FE003729%2F1
• 关键词: Self; compensating; GigaHertz; clocked; Quantum

All of our lives have been touched by cryptography at some point or another. From the simple secret diaries of childhood, through internet shopping and banking to the national security of governments, the scrambling of information to hide its contents from potential eavesdroppers is part of modern life.The most commonly used form of encryption today is the so-called public key system, as used in e-commerce and many other applications. This encryption method relies on the difficulty involved in reversing certain mathematical functions back from an answer to the initial starting values. This is analogous to baking a cake, where it is relatively easy to mix the ingredients and produce a cake but virtually impossible to take a finished cake and return to the initial ingredients. However, there is no long-term guarantee that these mathematical functions will remain as difficult to reverse. The development of quantum computers would allow relatively easy decryption of public key encrypted messages. It is fortunate that the same physics that may signal the end of public key encryption systems may also provide the solution in the form of quantum key distribution.Quantum key distribution (QKD) uses the science of quantum mechanics to provide a means of distributing the information needed to encrypt or decrypt a message (the key) in a way that provides verifiable security. It makes us of the fact that certain properties of a photon (a light particle ) cannot be determined with absolute certainty. If single binary digits (bits) of information are encoded onto single-photons using these properties, then any eavesdropper listening in on the key exchange will disturb the analysis of photons sufficiently to leave a virtual fingerprint on the transmission so that sender and receiver can detect the presence of the eavesdropper.QKD systems can either operate using optical fibres to transmit the single-photons to Bob or transmit them through the air. There has already been a large scale investment in a worldwide infrastructure of optical fibre to transmit telephone calls, so it could prove critical that a QKD system would have compatibility with this network. However, the detectors designed for use at the optimum transmission wavelengths for this fibre network have not yet attained the level of performance available from other detectors, leading to a massive reduction in the maximum rate of cryptographic key exchange.We have been able to use more advanced detectors designed for use at shorter wavelengths to develop an existing system for use in a campus sized implementation that is fully compatible with the telecommunications optical fibre. This QKD system is capable of transmission of bits generating up to several million bits per second, which is, to the best of our knowledge, the fastest clock rate QKD system currently in existence. At these bit transmission rates, after transmission and error correction techniques, real-time encrypted video conferencing becomes a possibility. This system has also been uniquely adapted for multi-user (one Alice and multiple Bobs) use.Although operating at world-class key exchange rates, this system does suffer from serious issues with long-term stability and is based on an arguably less secure QKD protocol. We propose to construct a series of three new, potentially much more stable, QKD systems using the expertise gained in the development of our existing system, all of which will use an arguably more secure protocol. The first two systems will be based on existing designs already operating at longer wavelengths but at much lower key exchange rates (ie a few thousands of bits per second). The third system will be based around a novel design that has never been fully implemented but has potentially greater security from eavesdropping attacks. With all three systems, the potential for multi-user operation will be investigated and demonstrations of multi-user networks will be made.

我们所有人的生活都在某个时候被密码学所触及。从简单的童年秘密日记，到网上购物和银行业务，再到政府的国家安全，对信息进行加密以隐藏其内容，使其不被潜在的窃听者窃听，这是现代生活的一部分。当今最常用的加密形式是所谓的公钥系统，用于电子商务和许多其他应用。这种加密方法依赖于将某些数学函数从答案逆回到初始值所涉及的困难。这类似于烘焙蛋糕，其中混合成分并制作蛋糕相对容易，但实际上不可能将成品蛋糕带回到初始成分。然而，无法保证这些数学函数将长期难以逆转。量子计算机的发展将允许相对容易地解密公钥加密的消息。幸运的是，可能标志着公钥加密系统终结的物理学也可能以量子密钥分发的形式提供解决方案。量子密钥分发（QKD）使用量子力学科学提供一种以提供可验证安全性的方式分发加密或解密消息（密钥）所需的信息的方法。它使我们认识到这样一个事实，即光子（一种光粒子）的某些性质不能绝对确定。如果使用这些属性将信息的单个二进制数字（比特）编码到单光子上，那么任何窃听者都会干扰光子的分析，从而在传输中留下虚拟指纹，这样发送者和接收者就可以检测到窃听者的存在。QKD系统可以使用光纤将单光子传输给Bob，也可以通过空气传输。已经有大规模的投资在全球光纤基础设施上传输电话，因此QKD系统与该网络的兼容性可能至关重要。然而，设计用于该光纤网络的最佳传输波长的检测器尚未达到其他检测器的性能水平，导致密钥交换的最大速率大幅降低。我们已经能够使用更先进的检测器，设计用于更短的波长，以开发一个现有的系统，用于校园规模的实施，完全兼容电信光纤。该QKD系统能够传输每秒产生高达数百万比特的比特，据我们所知，这是目前存在的最快时钟速率的QKD系统。在这些比特传输速率下，经过传输和纠错技术，实时加密视频会议成为可能。该系统也被独特地适配为多用户（一个Alice和多个Bob）使用。虽然以世界级的密钥交换率运行，但该系统确实存在长期稳定性方面的严重问题，并且基于可以说不太安全的QKD协议。我们建议使用我们现有系统开发中获得的专业知识构建一系列三个新的，可能更稳定的QKD系统，所有这些系统都将使用一个可以说更安全的协议。前两个系统将基于现有的设计，这些设计已经在更长的波长下运行，但密钥交换速率要低得多（即每秒几千比特）。第三个系统将基于一个从未完全实现过的新颖设计，但可能具有更大的安全性，不受窃听攻击。利用这三个系统，将调查多用户操作的潜力，并将进行多用户网络的演示。

项目成果

Single photon detection and quantum cryptography

单光子探测和量子密码学

• DOI: 10.1117/12.974666
• 发表时间: 2012
• 作者: Buller G

Quantum key distribution system in standard telecommunications fiber using a short wavelength single photon source

• DOI: 10.1063/1.3327427
• 发表时间: 2010-04-01
• 期刊: JOURNAL OF APPLIED PHYSICS
• 影响因子: 3.2
• 作者: Collins, R. J.;Clarke, P. J.;Buller, G. S.
• 通讯作者: Buller, G. S.

Single-photon detection in time-of-flight-depth imaging and quantum key distribution

飞行时间深度成像中的单光子检测和量子密钥分配

• DOI: 10.1117/12.873808
• 发表时间: 2011
• 作者: Buller G

Gigahertz Quantum Cryptography

千兆赫量子密码学

• 发表时间: 2010
• 作者: G Buller

Analysis of detector performance in a gigahertz clock rate quantum key distribution system

• DOI: 10.1088/1367-2630/13/7/075008
• 发表时间: 2011-07-22
• 期刊: NEW JOURNAL OF PHYSICS
• 影响因子: 3.3
• 作者: Clarke, Patrick J.;Collins, Robert J.;Buller, Gerald S.
• 通讯作者: Buller, Gerald S.