A quantum encryption design featuring confusion, diffusion, and mode of operation

TL;DR

This paper introduces a novel non-one-time-pad quantum encryption scheme that employs confusion, diffusion, and a mode of operation to enhance security and practicality in quantum cryptography.

Contribution

It presents a new quantum encryption method that combines confusion, diffusion, and block cipher modes, addressing limitations of existing quantum encryption algorithms.

Findings

Provides complex key-ciphertext relation (confusion)

Ensures complex plaintext-ciphertext relation (diffusion)

Supports practical multi-block encryption mode

Abstract

Quantum cryptography -- the application of quantum computing techniques to cryptography has been extensively investigated. Two major directions of quantum cryptography are quantum key distribution (QKD) and quantum encryption, with the former focusing on secure key distribution and the latter focusing on encryption using quantum algorithms. In contrast to the success of the QKD, the development of quantum encryption algorithms is limited to designs of mostly one-time pads (OTP) that are unsuitable for most communication needs. In this work we propose a non-OTP quantum encryption scheme utilizing a quantum state creation process to encrypt messages. As essentially a non-OTP quantum block cipher the method stands out against existing methods with the following features: 1. complex key-ciphertext relation (i.e. confusion) and complex plaintext-ciphertext relation (i.e. diffusion); 2. mode of operation design for practical encryption on multiple blocks. These features provide key reusability and protection against eavesdropping and standard cryptanalytic attacks.