Towards Quantum Enigma Cipher II-A protocol based on quantum illumination-

TL;DR

This paper explores a quantum enigma cipher protocol utilizing quantum illumination to enhance security by exploiting quantum noise and entanglement, making it resistant to brute-force attacks.

Contribution

It introduces a novel quantum enigma cipher protocol based on quantum illumination, highlighting how quantum effects can improve security against brute-force attacks.

Findings

Quantum illumination can differentiate error performance between legitimate and eavesdropper.

Entanglement enhances the legitimate receiver's ability to decode ciphertext.

Quantum noise randomization is crucial for the security of the cipher.

Abstract

This research note II introduces a way to understand a basic concept of the quantum enigma cipher. The conventional cipher is designed by a mathematical algorithm and its security is evaluated by the complexity of the algorithm in security analysis and ability of computers. This kind of cipher can be decrypted with probability one in principle by the Brute force attack in which an eavesdropper tries all the possible keys based on the correct ciphertext and some known plaintext. A cipher with quantum effects in physical layer may protect the system from the Brute force attack by means of the quantum no cloning theorem and randomizations based on quantum noise effect. The randomizations for the ciphertext which is the output from the mathematical encryption box is crucial to realize a quantum enigma cipher. Especially, by randomizations, it is necessary to make a substantial difference in accuracy of ciphertext in eavesdropper's observation and legitimate user's observation. The quantum illumination protocol can make a difference in error performance of the legitimate's receiver and the eavesdropper's receiver. This difference is due to differences in ability of the legitimate's receiver with entanglement and the eavesdropper's receiver without entanglement. It is shown in this note that the quantum illumination can be employed as an element of the most simple quantum enigma cipher.