Design and Analysis of Secure Quantum Communication Schemes

Mitali Sisodia

This thesis is focused on the design and analysis of quantum communication protocols. Several schemes for quantum communication have been introduced in the recent past. For example, quantum teleportation, dense coding, quantum key distribution, quantum secure direct communication, etc., have been rigorously studied in the last 2-3 decades. Specifically, a specific attention of the present thesis is to study the quantum teleportation schemes with entangled orthogonal and nonorthogonal states and their experimental realization, but not limited to it. We have also studied some aspects of quantum cryptography.

Chitra Shukla

Santanu Majhi, Debajyoti Bera

Quantum communication protocols can be designed to detect eavesdropping attacks, something that classical technologies are unable to do since classical information can be replicated in a non-destructive manner. Eavesdropping detection is, therefore, a standard feature in all the proposed quantum secret sharing (QSS) protocols. However, detection is often done by a statistical analysis of the outcome of multiple decoy rounds, and this causes a significant communication overhead. In our quest for a QSS protocol that works even in one round, we came across a one-shot secret-sharing framework proposed by Hsu (Phys. Rev. A 2003). The scheme was designed to work over public channels without requiring multiple rounds to detect eavesdropping but it lacked a thorough security analysis. In this work we present a complete characterisation of the correctness and security properties of this framework. Our characterisation allowed us to improve the original protocol to be more resistant towards eavesdropping. However, we prove a couple of impossibility results, including one that dictates that complete security against an eavesdropper is not possible in this framework. Thus, it is not possible to design a perfect QSS using this framework.

Mitali Sisodia

This thesis is focused on the design and analysis of quantum communication protocols. Several schemes for quantum communication have been introduced in the recent past. For example, quantum teleportation, dense coding, quantum key distribution, quantum secure direct communication, etc., have been rigorously studied in the last 2-3 decades. Specifically, a specific attention of the present thesis is to study the quantum teleportation schemes with entangled orthogonal and nonorthogonal states and their experimental realization, but not limited to it. We have also studied some aspects of quantum cryptography.

Seema Ukidve, Ramsagar Yadav, Mukhdeep Singh Manshahia +1 more