Cryptanalysis of an Efficient Hierarchical Identity Based Signature Scheme in the Standard Model

摘要

Hierarchical identity based signature generalizes the concept of identity based signature to organization hierarchy. Till now, there are many interesting hierarchical identity based signature schemes. At ChinaCrypt'08, Ren and Gu claimed to construct an efficient hierarchical identity based signature scheme based on the q-SDH problem with full security in the standard model. They claimed their scheme has short public parameters, high efficiency and a tight reduction. But in this paper we give an attack to their scheme to show their scheme is not secure.