Attribute Based Signatures for Bounded Multi-level Threshold Circuits

摘要

Attribute based signature (ABS) permits users produce signatures using any predicate of attributes issued from an attribute authority. ABS disallows any group of colluding users to forge a signature based on a predicate of attributes which they do not individually satisfy. Earlier schemes in this direction are either in the generic group model or support only single-level threshold predicates. In this paper, we propose the first attribute based signature schemes that support bounded flexible multi-level threshold predicates. Our first scheme is proved in the random oracle model and the second does not rely on random oracles. We provide security models for unforgeability and attribute-privacy and formally prove the same under the Computational Diffie-Hellman assumption.