Efficient lattice-based revocable attribute-based encryption against decryption key exposure for cloud file sharing.

Area of Science:

• Cryptography and Information Security
• Cloud Computing Security
• Post-Quantum Cryptography

Background:

• Cloud file sharing (CFS) is vital for enterprises but faces security challenges due to untrusted providers.
• Existing access control methods rely on traditional cryptography vulnerable to quantum computing.
• Need for secure, efficient, and post-quantum resistant access control for sensitive data in CFS.

Purpose of the Study:

• To develop a novel lattice-based Ciphertext-Policy Attribute-Based Encryption (CP-ABE) scheme for secure CFS.
• To enhance security against quantum threats and improve efficiency in access control and user management.
• To achieve decryption key exposure resistance (DKER) and enable multi-authority setups for cross-enterprise sharing.

Main Methods:

• Design of a lattice-based CP-ABE scheme using the ring learning with error (RLWE) problem.
• Implementation of indirect revocation and binary tree structures for efficient user and group management.
• Incorporation of re-randomization techniques for DKER and a multi-authority framework.

Main Results:

• The proposed scheme offers enhanced security against quantum attacks.
• Efficient user revocation and dynamic group management are achieved.
• Demonstrated high efficiency and practicality through formal security proofs and experimental analysis, including DKER and multi-authority support.

Conclusions:

• The lattice-based CP-ABE scheme provides a secure and efficient solution for CFS in the post-quantum era.
• The scheme effectively addresses challenges of untrusted cloud providers, user revocation, and cross-enterprise data sharing.
• The proposed approach is practical and robust, paving the way for more secure cloud environments.