Hierarchical Identity-Based Signature over Verifiable Random Function

Abstract

Hierarchical computation makes an important role in constructing identity-based signature (IBS) since it provides a delegation mechanism to IBS, which results in the Hierarchical identity-based signature (HIBS). HIBS has widely potential applications in the large networks. However, the constructions available cannot propose a good trade-off for the private keys and signatures since the size of private keys or signatures depends on the identity depth. In this paper, a new hierarchical computation algorithm is introduced to construct HIBS scheme. The new scheme achieves O(1)-size private keys and signatures, which are independent of identity depth. It is the best trade-off at present. Furthermore, under the \(n+1-weak\) Computational Diffie-Hellman Exponent (\(n+1-wCDH\)) assumption, the scheme is provably secure against existential forgery in the standard model.