In view of the emerging cyber threats, hardening authentication and communication systems has grown as an imperative task. This survey paper presents a detailed review of state-of-the-art security paradigms in the context of authentication and communication. Starting with an analysis of different authentication methodologies, covering password-based, biometric, and multifactor authentication, this paper reviews the strengths, weaknesses, and applicability of these techniques in context. It will also examine, in some detail, symmetric and asymmetric techniques of encryption, cryptographic protocols like SSL/TLS, SSH, IPSec, etc., that are relevant to setting up secure channels of communication. Key distribution mechanisms, digital signatures, and public key infrastructures, which are important building blocks in any robust framework for securing communication, are dealt with at length. It also examines some of the emerging technologies in blockchain and quantum cryptography as applied in authentication and communication security. Through this in-depth review, the paper hopes to shed light on the fast-changing landscape of security concepts and underscore their indispensability with regard to confidentiality, integrity, and authentication of contemporary information systems.