Brief History of Quantum Cryptography: A Personal Perspective

Quantum Key Distribution

This chapter describes the application of lasers, specifically diode lasers, in the area of quantum key distribution (QKD). First, we motivate the distribution of cryptographic keys based on quantum physical properties of light, give a brief introduction to QKD assuming the reader has no or very little knowledge about cryptography, and briefly present the state-of-the-art of QKD. In the second half of the chapter we describe, as an example of a real-world QKD system, the system deployed between the University of Calgary and SAIT Polytechnic. We conclude the chapter with a brief discussion of q…

Scalable quantum random number generator for cryptography based on the random flip-flop approach

For globally connected devices like smart phones, personal computers and Internet-of-things devices, the ability to generate random numbers is essential for execution of cryptographic protocols responsible for information security. Generally, a random number generator should be small, robust, utilize as few hardware and energy resources as possible, yet provide excellent randomness at a high enough speed (bitrate) for a given purpose. In this work we present a quantum random number generator (QRNG) which makes use of a photoelectric effect in single-photon avalanche diodes (SPADs) as a source …

Private quantum codes: introduction and connection with higher rank numerical ranges

We give a brief introduction to private quantum codes, a basic notion in quantum cryptography and key distribution. Private code states are characterized by indistinguishability of their output states under the action of a quantum channel, and we show that higher rank numerical ranges can be used to describe them. We also show how this description arises naturally via conjugate channels and the bridge between quantum error correction and cryptography.

分布式相位参考量子密钥分发协议的仿真

Simulations of distributed-phase-reference quantum key distribution protocols

本文在ANSYS Interconnect平台上仿真了分布式相位参考量子密钥分发协议的实际实现，并评估了后闪光、木马及探测器致盲等窃听攻击。

General Linear Group Action on Tensors: A Candidate for Post-Quantum Cryptography

Starting from the one-way group action framework of Brassard and Yung (Crypto '90), we revisit building cryptography based on group actions. Several previous candidates for one-way group actions no longer stand, due to progress both on classical algorithms (e.g., graph isomorphism) and quantum algorithms (e.g., discrete logarithm). We propose the general linear group action on tensors as a new candidate to build cryptography based on group actions. Recent works (Futorny--Grochow--Sergeichuk, Lin. Alg. Appl., 2019) suggest that the underlying algorithmic problem, the tensor isomorphism problem,…

Quantum Communication and Decoherence

In this contribution we will give a brief overview on the methods used to overcome decoherence in quantum communication protocols. We give an introduction to quantum error correction, entanglement purification and quantum cryptography. It is shown that entanglement purification can be used to create ``private entanglement'', which makes it a useful tool for cryptographic protocols.

Quantum key distribution via quantum encryption

A quantum key distribution protocol based on quantum encryption is presented in this Brief Report. In this protocol, the previously shared Einstein-Podolsky-Rosen pairs act as the quantum key to encode and decode the classical cryptography key. The quantum key is reusable and the eavesdropper cannot elicit any information from the particle Alice sends to Bob. The concept of quantum encryption is also discussed.

公钥密码学中的量子算术电路

Quantum Arithmetic Circuits in Public-Key Cryptography

介绍公钥密码学中量子算术电路，阐述其面临的设计挑战，强调基于测量的反计算等优化策略，回顾基本算术运算的最新设计及量子密码分析中容错运行时和资源估计技术，为评估量子密码分析能力提供基础。

Network-Centric Quantum Communications with Application to Critical Infrastructure Protection

Network-centric quantum communications (NQC) - a new, scalable instantiation of quantum cryptography providing key management with forward security for lightweight encryption, authentication and digital signatures in optical networks - is briefly described. Results from a multi-node experimental test-bed utilizing integrated photonics quantum communications components, known as QKarDs, include: quantum identification; verifiable quantum secret sharing; multi-party authenticated key establishment, including group keying; and single-fiber quantum-secured communications that can be applied as a s…

量子查询复杂度简介

A Brief Introduction to Quantum Query Complexity

本文介绍量子查询复杂度，重点阐述四种求解下界的主要技术及对手方法推导上界的双重作用，为初学者和研究人员提供自成体系的入门指南。

后量子安全：起源、基础与采用

Post-Quantum Security: Origin, Fundamentals, and Adoption

本文阐述后量子安全的起源与基础，介绍格基密码学及Kyber和Dilithium两种量子安全算法，并概述政府与行业的标准化行动，旨在提供自包含的数学基础。

Information Gain vs. State Disturbance in Quantum Theory

The engine that powers quantum cryptography is the principle that there are no physical means for gathering information about the identity of a quantum system's state (when it is known to be prepared in one of a set of nonorthogonal states) without disturbing the system in a statistically detectable way. This situation is often mistakenly described as a consequence of the ``Heisenberg uncertainty principle.'' A more accurate account is that it is a unique feature of quantum phenomena that rests ultimately on the Hilbert space structure of the theory along with the fact that time evolutions for…

Insecurity of Quantum Secure Computations

It had been widely claimed that quantum mechanics can protect private information during public decision in for example the so-called two-party secure computation. If this were the case, quantum smart-cards could prevent fake teller machines from learning the PIN (Personal Identification Number) from the customers' input. Although such optimism has been challenged by the recent surprising discovery of the insecurity of the so-called quantum bit commitment, the security of quantum two-party computation itself remains unaddressed. Here I answer this question directly by showing that all ``one-si…