Conditional Identity-Based Broadcast Proxy Re-Encryption and Its Application to Cloud Email

Abstract

This research proposes a novel Conditional Identity-Based Broadcast Proxy Re-Encryption (CIB-BPRE) scheme to enhance security and privacy in cloud email systems. The scheme allows a delegator to grant authorized recipients access to their encrypted emails while maintaining fine-grained control over decryption permissions. This is achieved by incorporating conditional attributes into the re-encryption process, ensuring only recipients satisfying specific conditions can decrypt the forwarded emails. The proposed scheme addresses the limitations of existing email delegation methods by providing enhanced security and flexibility, preventing unauthorized access and data breaches. Our evaluation demonstrates the efficiency and security of the proposed CIB-BPRE scheme, making it a suitable solution for secure cloud email delegation.

Introduction

Cloud email services offer convenience and scalability, but they pose significant security and privacy challenges. Forwarding emails requires trust in the forwarding party, who potentially gains access to sensitive information. Current solutions like traditional proxy re-encryption lack the flexibility to control decryption based on recipient attributes. Identity-Based Encryption (IBE) simplifies key management, but traditional IBE schemes do not inherently support delegation. A secure and efficient solution is needed to enable email delegation while mitigating the risk of unauthorized access and maintaining user privacy. This research addresses this gap by proposing a conditional identity-based broadcast proxy re-encryption scheme specifically tailored for cloud email applications.

Objectives

• Design a secure and efficient CIB-BPRE scheme for cloud email.
• Implement a prototype system demonstrating the scheme's functionality.
• Analyze the performance and security of the proposed scheme.