Encryption and Privacy in Cloud Computing: A Comprehensive Review

Abstract

Cloud computing has revolutionized data storage, processing, and service delivery by offering scalable, cost-effective, and on-demand access to computing resources. However, with this paradigm shift, issues surrounding encryption and privacy have become pressing concerns for enterprises, governments, and individuals. The outsourcing of sensitive data to third-party cloud providers introduces risks such as unauthorized access, data breaches, insider threats, and jurisdictional ambiguities. Encryption, as a fundamental technique, provides a primary line of defense against these risks, but challenges remain in terms of key management, performance overhead, and compatibility with emerging applications such as big data analytics and the Internet of Things (IoT). This paper presents a comprehensive review of encryption mechanisms and privacy-preserving approaches in cloud environments. It explores classical encryption techniques, homomorphic encryption, attribute-based encryption, and searchable encryption, while also discussing privacy models such as differential privacy and anonymization. The review emphasizes the balance between robust security and system efficiency, highlighting the trade-offs between usability, scalability, and confidentiality. Further, the study identifies open research challenges including quantum-resistant cryptography, decentralized privacy frameworks, and regulatory compliance in multi-cloud settings. By synthesizing current advancements and ongoing debates, this review contributes to understanding the evolving landscape of encryption and privacy in cloud computing.