KCQ: A New Approach to Quantum Cryptography I. General Principles and Key Generation

TL;DR

The paper introduces KCQ, a quantum cryptography method leveraging shared secret keys and quantum detection theory to enhance security and generate fresh keys, differing from traditional protocols.

Contribution

It develops a new quantum cryptography approach based on quantum detection and communication theory, providing a general information-theoretic framework and concrete system illustration.

Findings

Better error performance for legitimate users compared to attackers

Ability to generate fresh keys from quantum advantage

Contrast with traditional detection/coding protocols

Abstract

A new approach to quantum cryptography to be called KCQ, keyed communication in quantum noise, is developed on the basis of quantum detection and communication theory for classical information transmission. By the use of a shared secret key that determines the quantum states generated for different data bit sequences, the users may employ the corresponding optimum quantum measurement to decode the data. This gives them a better error performance than an attacker who does not know the key when she makes her quantum measurement, and an overall generation of a fresh key may be obtained from the resulting advantage. This principle is illustrated in the operation of a concrete qubit system A general information-theoretic description of the overall approach will be presented, and contrasted with the detection/coding description necessary for specific protocols.