Applicability of OR-Proof Techniques to Hierarchical Identity-Based Identification

摘要

We discuss the applicability of the well known OR-proof technique to hierarchical identity-based identification (HIBI) protocols for enhancing their security. We first describe formal security definitions for HIBI protocol not only in the adaptive hierarchical-identity setting but also in both "static" and "weak selective" hierarchical-identity settings. Next, we investigate whether the security enhancement transformations for identity-based identifications presented at ACNS 2012, which is based on the OR-proof technique, can be applied to HIBI protocols. We formally prove that several of these transformations are applicable to HIBI with slight modification. Curiously, the rest do not seem applicable, which stems from hierarchy and delegation. We also present a variant transformation and show that it can enhance the security of HIBI protocols in all three hierarchical-identity settings.