Secure Quantum Communication with Orthogonal States

TL;DR

This paper reviews recent developments in orthogonal-state-based secure quantum communication protocols, highlighting their transition from theoretical concepts to experimental realizations and extensions beyond quantum key distribution.

Contribution

It provides a comprehensive overview of recent orthogonal-state-based protocols, including their experimental realization and extension to other cryptographic tasks.

Findings

Orthogonal-state protocols have been experimentally realized.

These protocols extend beyond quantum key distribution.

Recent protocols enhance secure quantum communication capabilities.

Abstract

In majority of protocols of secure quantum communication (such as, BB84, B92, etc.), the unconditional security of the protocols are obtained by using conjugate coding (two or more mutually unbiased bases). Initially all the conjugate-coding-based protocols of secure quantum communication were restricted to quantum key distribution (QKD), but later on they were extended to other cryptographic tasks (such as, secure direct quantum communication and quantum key agreement). In contrast to the conjugate-coding-based protocols, a few completely orthogonal-state-based protocols of unconditionally secure QKD (such as, Goldenberg-Vaidman (GV) and N09) were also proposed. However, till the recent past orthogonal-state-based protocols were only a theoretical concept and were limited to QKD. Only recently, orthogonal-state-based protocols of QKD are experimentally realized and extended to cryptographic tasks beyond QKD. This paper aims to briefly review the orthogonal-state-based protocols of secure quantum communication that are recently introduced by our group and other researchers.