A comprehensive review of cryptographic techniques and emerging trends in modern cybersecurity

Cryptography is a fundamental pillar of modern cybersecurity, ensuring confidentiality, integrity, authentication, and non-repudiation in digital communication systems. This paper presents a comprehensive review of classical and modern cryptographic techniques, including symmetric encryption, asymmetric encryption, and cryptographic hash functions. Widely adopted algorithms such as Advanced Encryption Standard (AES), Rivest -Shamir-Adleman (RSA), and Elliptic Curve Cryptography (ECC) are analyzed in terms of performance, security, and application domains. Recent advancements such as homomorphic encryption, blockchain-based cryptography, and post-quantum cryptography are also explored. Comparative analysis highlights trade-offs between computational efficiency, key size, and resistance to emerging threats such as quantum computing. Furthermore, challenges such as key management, scalability, and implementation vulnerabilities are discussed. The paper concludes by identifying future research directions focusing on lightweight, quantum-resistant, and privacy-preserving cryptographic systems for next-generation applications including IoT, cloud computing, and artificial intelligence-driven environments.