International Research Journal of Education and Technology

Cloud computing has revolutionized data storage and sharing by providing scalable and on-demand services. However, secure data sharing in semi-trusted cloud environments remains a major challenge. Traditional encryption mechanisms require repetitive encryption for multiple users, increasing computational overhead and key management complexity. Identity-Based Broadcast Proxy Re-Encryption (IB-BPRE) improves efficiency but suffers from dependency on the data owner during user revocation and key renewal processes.

This paper proposes a Revocable Identity-Based Broadcast Proxy Re-Encryption (RIB-BPRE) scheme that enables secure broadcast data sharing with efficient and dynamic user revocation. The proposed system eliminates continuous dependency on the data owner during key updates while maintaining strong confidentiality guarantees. The cloud server acts as a semi-trusted proxy that transforms ciphertext without accessing plaintext. Performance evaluation demonstrates improved scalability, reduced computational overhead, and secure access control suitable for real-world cloud applications.

Keywords: Cloud Security, Identity-Based Encryption, Proxy Re-Encryption, Broadcast Encryption, User Revocation, Cryptography.