Enhanced Access Control for Secure Cloud Data Storage and Sharing Using Elliptic Curve Cryptography

This paper presents the development of an advanced access control mechanism for secure cloud data storage and sharing, integrating cryptographic techniques to prevent unauthorized access, insider threats, and economic denial of sustainability (EDoS) attacks. The proposed system, termed "Digital Signature-Based Trio Access Control with Key Shares," ensures three key functionalities: (1) Ciphertext-Policy Attribute-Based Encryption (CP-ABE) to provide fine-grained access control, ensuring that only authorized users can decrypt cloud-stored data, (2) Digital Signature verification using Elliptic Curve Cryptography (ECC) to authenticate and validate user requests, preventing unauthorized access and network-based attacks, and (3) Key Sharing Mechanism to prevent key theft and insider threats by splitting encryption keys between the cloud provider and the data user. Implemented using Java, the system incorporates state-of-the-art cryptographic techniques to enhance security while maintaining computational efficiency. The access control framework effectively mitigates security risks such as excessive download requests and unauthorized key access, making it a robust solution for industries dealing with sensitive cloud-stored data. Performance evaluations, including encryption efficiency, request validation speed, and security impact analysis, demonstrate that the proposed mechanism provides reliable and secure data access control. This study highlights the significance of multi-layered security frameworks in cloud storage environments, offering a scalable and efficient solution for modern cloud-based applications. Index terms: Cloud Security, Access Control, Ciphertext-Policy Attribute-Based Encryption (CP-ABE), Digital Signature, Elliptic Curve Cryptography (ECC), Key Sharing Mechanism, Economic Denial of Sustainability (EDoS) Attacks, Cloud Data Protection, Cryptographic Security, Secure Cloud Storage, Insider Threat Mitigatio