Multiparty quantum cryptographic protocol

TL;DR

This paper introduces a secure, efficient multiparty quantum cryptographic protocol that encodes classical information using unitary operations on entangled qubits, allowing for deterministic key distribution and eavesdropper detection.

Contribution

It presents a novel multiparty quantum cryptographic scheme that combines key distribution and eavesdropper detection in a single protocol with high efficiency.

Findings

Protocol is secure against intercept-resend attacks.

Achieves deterministic transfer of two classical bits per entangled pair.

Enables simultaneous key distribution and eavesdropper detection.

Abstract

We propose a multiparty quantum cryptographic protocol. Unitary operators applied by Bob and Charlie, on their respective qubits of a tripartite entangled state encodes a classical symbol that can be decoded at Alice's end with the help of a decoding matrix. Eve's presence can be detected by the disturbance of the decoding matrix. Our protocol is secure against intercept-resend attacks. Furthermore, it is efficient and deterministic in the sense that two classical bits can be transferred per entangled pair of qubits. It is worth mentioning that in this protocol same symbol can be used for key distribution and Eve's detection that enhances the efficiency of the protocol.