Quantum cryptography: key distribution and beyond

Uniquely among the sciences, quantum cryptography has driven both foundational research as well as practical real-life applications. We review the progress of quantum cryptography in the last decade, covering quantum key distribution and other applications.Comment: It's a review on quantum cryptography and it is not restricted to QK

Quantum Cryptography: Key Distribution and Beyond

Uniquely among the sciences, quantum cryptography has driven both foundational research as well as practical real-life applications. We review the progress of quantum cryptography in the last decade, covering quantum key distribution and other applications.Quanta 2017; 6: 1–47

Field test of a practical secure communication network with decoy-state quantum cryptography

We present a secure network communication system that operated with decoy-state quantum cryptography in a real-world application scenario. The full key exchange and application protocols were performed in real time among three nodes, in which two adjacent nodes were connected by approximate 20 km of commercial telecom optical fiber. The generated quantum keys were immediately employed and demonstrated for communication applications, including unbreakable real-time voice telephone between any two of the three communication nodes, or a broadcast from one node to the other two nodes by using one-time pad encryption.Comment: 10 pages, 2 figures, 2 tables, typos correcte

Fast and secure key distribution using mesoscopic coherent states of light

This work shows how two parties A and B can securely share sequences of random bits at optical speeds. A and B possess true-random physical sources and exchange random bits by using a random sequence received to cipher the following one to be sent. A starting shared secret key is used and the method can be described as an unlimited one-time-pad extender. It is demonstrated that the minimum probability of error in signal determination by the eavesdropper can be set arbitrarily close to the pure guessing level. Being based on the $M$-ry encryption protocol this method also allows for optical amplification without security degradation, offering practical advantages over the BB84 protocol for key distribution.Comment: 11 pages and 4 figures. This version updates the one published in PRA 68, 052307 (2003). Minor changes were made in the text and one section on Mutual Information was adde

Learners' shifting perceptions of randomness.

This is a phenomenographic study of learners’ perceptions of randomness. Underpinning the study is a sense of randomness as a dynamic process, in which events emerge unpredictably from a generating process, into the determined past, through the curtain separating past from future. Previous research into perceptions of randomness has often used tasks in which people are asked to recognise randomness in a given sequence of outcomes. Other research has asked people to make up sequences of random outcomes. Such tasks do not carry the sense of randomness as dynamic. Interview tasks in this study were designed to present the dynamic sense of randomness using outcomes from random generators such as dice, coins and sampling bags in situ. Interviewees were invited to talk about their experiences of making sense of the emerging sequence of outcomes. The analysis of the interview transcripts addressed two related questions: • What do learners believe about randomness? • To what situations and circumstances do learners consider randomness to be an appropriate model? The first question encompasses learners’ expectations of a random generator and the methods, strategies and heuristics by which learners discern what is random from what is not. Drawing on local and global meanings of randomness identified by Pratt (1998), the thesis argues that learners’ perspectives on randomness shift rapidly and frequently between the local and global as the learners seek to interpret the observed outcomes. Learners’ interpretations of and beliefs about randomness are found to have significant impact upon the kinds of situations to which learners are able and willing to apply the model of randomness