Lightweight mediated semi-quantum key distribution protocol with a dishonest third party based on Bell states

Area of Science:

• Quantum Information Science
• Cryptography
• Quantum Communication

Background:

• Mediated semi-quantum key distribution (MSQKD) enables secure key sharing between classical users via a third party (TP).
• Existing MSQKD protocols often require expensive detectors for classical users and assume an honest TP.
• These limitations hinder the practical application and security of current MSQKD protocols.

Purpose of the Study:

• To propose a novel MSQKD protocol that addresses the limitations of existing methods.
• To enable secure key distribution without requiring classical users to have expensive detectors.
• To ensure security even when the third party is untrustworthy (dishonest).

Main Methods:

• Utilizes Bell states as the quantum resource for key distribution.
• Designs a protocol where classical participants do not need specialized Trojan horse detectors.
• Develops a security framework that accounts for a potentially dishonest third party.

Main Results:

• The proposed MSQKD protocol eliminates the need for expensive detectors for classical participants.
• It demonstrates security against common quantum attacks, even with a dishonest TP.
• Classical participants require only two basic quantum capabilities.

Conclusions:

• The developed MSQKD protocol offers enhanced practicality compared to existing solutions.
• It overcomes the security and cost barriers associated with current MSQKD systems.
• This work contributes to more accessible and robust quantum key distribution.