Unbounded and revocable hierarchical identity-based encryption with adaptive security, decryption key exposure...

Area of Science:

• Cryptography
• Computer Science
• Information Security

Background:

• Identity-based cryptosystems require revocation functionality and hierarchy key delegation.
• Existing revocable hierarchical identity-based encryption (RHIBE) schemes are often insecure or have fixed hierarchical depth limitations.
• Scalability and adaptability are key challenges in current RHIBE systems.

Purpose of the Study:

• To propose a novel unbounded RHIBE scheme.
• To achieve adaptive security, decryption key exposure resilience, and short public system parameters.
• To develop a scalable system accommodating dynamic user levels without system restarts.

Main Methods:

• Development of a new unbounded RHIBE scheme.
• Application of carefully designed hybrid games to prove adaptive security.
• Adaptation of the dual system encryption methodology for unbounded and revocable HIBE.

Main Results:

• Introduction of the first adaptively secure unbounded RHIBE scheme.
• The proposed scheme demonstrates inherent scalability for user hierarchy adaptation.
• The scheme offers resilience against decryption key exposure and uses short public parameters.

Conclusions:

• The proposed unbounded RHIBE scheme overcomes limitations of previous constructions.
• This work presents a significant advancement in secure and scalable identity-based encryption.
• The scheme provides a robust solution for dynamic and secure hierarchical key management.