Protocols for Secure Quantum Transmission: A Review of Recent Developments

Abstract

Data transmission has always been vulnerable to eavesdropping. Conventional cryptography has provided security in data communication, however it has some limitations when dealing with passive eavesdropping. Recently, the quantum mechanics has made a remarkable entry in the field of data communication. Now, it is possible to construct cryptographic communication systems which detect unauthorized eavesdropping and guarantee its prevention. Several protocols have been devised to implement such systems e.g., BB84, B92 and EPR. The famous BB84 protocol describes quantum encryption in terms of polarization states of a photon. The secret information is transmitted via secure quantum channel followed by a public conversation for verification and reconciliation. The B92 protocol is an extension of BB84 which shows how photons with non-orthogonal states can be used to distribute a secret key. The EPR protocol utilizes an entangled photon pair for encryption–one photon from this pair is transmitted towards the destination while keeping the other at the source; the destination photon describes the state of the source photon, failing to which confirms the intrusion. This paper presents a study of these protocols and a review on the recent developments in the field of secure quantum transmission.