Revocable identity-based proxy re-signature against signing key exposure

Area of Science:

• Cryptography
• Information Security
• Computer Science

Background:

• Identity-based proxy re-signature (IDPRS) enables signature transformation but lacks user revocation.
• Existing IDPRS schemes do not support dynamic user management, posing security risks.

Purpose of the Study:

• Introduce revocable identity-based proxy re-signature (RIDPRS) for dynamic user management.
• Develop a server-aided RIDPRS (SA-RIDPRS) for improved verification performance.
• Enhance the security and efficiency of IDPRS schemes with revocation capabilities.

Main Methods:

• Formal definition and security model for RIDPRS.
• Construction of a concrete RIDPRS scheme secure against key exposure.
• Extension to SA-RIDPRS with security proofs against adaptive attacks.
• Performance analysis of computational complexity for revocation.

Main Results:

• Proposed RIDPRS scheme is existentially unforgeable against adaptive chosen identity and message attacks.
• SA-RIDPRS scheme is secure against adaptive chosen message and collusion attacks.
• Both schemes offer efficient user revocation with low computational overhead.
• SA-RIDPRS reduces verification computation to one bilinear pairing and four exponentiations.

Conclusions:

• RIDPRS and SA-RIDPRS effectively address the need for user revocation in IDPRS systems.
• SA-RIDPRS provides significant performance improvements in signature verification compared to existing IDPRS schemes.
• The proposed schemes offer a practical solution for secure and dynamic information systems.