ENCRYPTION AND DECRYPTION IN COMPUTER SCIENCE: ALGORITHMS, APPLICATIONS, AND SECURITY CHALLENGES

Abstract

Encryption and decryption are fundamental mechanisms in computer science that safeguard information confidentiality, integrity, and accessibility. This paper comprehensively reviews traditional and modern cryptographic techniques, including symmetric, asymmetric, and hybrid encryption algorithms, highlighting their mechanisms, advantages, and limitations. Core algorithms such as AES, DES, Blowfish, RSA, ECC, and Diffie Hellman are discussed with respect to their security performance, computational efficiency, and suitability for different digital environments. The study explores advanced developments such as homomorphic encryption, optical encryption, neural network-assisted cryptography, and blockchain-based key management systems, which offer enhanced privacy and efficiency in secure communications. Special attention is given to the emerging challenges posed by quantum computing, which threatens conventional encryption standards, and to the evolving field of post-quantum cryptography that aims to build quantum-resistant algorithms. Furthermore, the paper highlights the role of artificial intelligence and lightweight cryptography in securing IoT systems and resource-constrained devices. The review concludes that the continuous advancement of cryptographic systems, integration of AI-driven cybersecurity measures, and development of quantum-safe encryption standards are crucial for ensuring robust data protection in the rapidly evolving digital ecosystem.