A short review on quantum identity authentication protocols: how would Bob know that he is talking with Alice?

Secure communication has achieved a new dimension with the advent of the schemes of quantum key distribution (QKD) as in contrast with classical cryptography, quantum cryptography can provide unconditional security. However, a successful implementation of a scheme for QKD requires identity authentication as a prerequisite. A security loophole in the identity authentication scheme may lead to the vulnerability of the entire secure communication scheme. Consequently, identity authentication is extremely important, and in the last three decades several schemes for identity authentication using quantum resources have been proposed. The chronological development of these protocols, which are now referred to as quantum identity authentication (QIA) protocols, is briefly reviewed here with specific attention to the causal connection involved in their development. The existing protocols are classified on the basis of the required quantum resources, and their relative merits and demerits are analyzed. Further, in the process of the classification of the protocols for QIA, it is observed that the existing protocols can also be classified in a few groups based on the inherent computational tasks used to design the protocols. Realization of these symmetries has led to the possibility of designing a set of new protocols for quantum identity authentication, which are based on the existing schemes for the secure computational and communication tasks. The security of such protocols is also critically analyzed.