An efficient lattice-based identity-based proxy Re-encryption scheme with direct revocation for cloud storage

Area of Science:

• Cryptography
• Cloud Security
• Data Privacy

Background:

• Secure cloud data sharing and user revocation are critical due to increasing data volume and sharing.
• Existing proxy re-encryption (PRE) and identity-based encryption (IBE) schemes often rely on bilinear pairings vulnerable to quantum attacks and lack efficient revocation.
• There is a need for robust, quantum-resistant solutions with dynamic access control and efficient revocation.

Purpose of the Study:

• To propose a novel identity-based directly revocable proxy re-encryption (IBPRE-DR) scheme.
• To address the limitations of existing schemes, including quantum vulnerability and inefficient revocation.
• To enhance secure data sharing in cloud environments with dynamic access control.

Main Methods:

• Developed an IBPRE-DR scheme based on the Learning With Errors (LWE) assumption, a lattice-based cryptographic approach.
• Implemented a complete subtree algorithm for efficient and direct user revocation.
• Incorporated a dual-key mechanism to differentiate re-encryption and decryption keys, preventing collusion.

Main Results:

• The proposed IBPRE-DR scheme provides direct and dynamic user revocation without relying on a key generation center (KGC).
• The scheme is resistant to quantum threats due to its LWE-based foundation.
• It effectively mitigates collusion attacks through a dual-key mechanism and supports multi-bit encryption with fixed private key lengths.

Conclusions:

• This work presents the first lattice-based identity-based proxy re-encryption scheme with direct user revocation under the LWE assumption.
• The IBPRE-DR scheme offers enhanced security, efficient revocation, and quantum resistance for cloud data sharing.
• Both theoretical analysis and experimental results validate the scheme's effectiveness and feasibility.