Public Key Replacement Attack on Two Certificateless Blind Signature Schemes

摘要

Certificateless public key cryptography as a new paradigm was introduced by Al-Riyami and Paterson in Asiacrypt 2003. It simplifies the complex certificate management in the traditional public key cryptography and resolves the inherent key escrow problem in the identity-based cryptography. Blind signature plays a central role in applications such as e-cash and e-voting systems, and so on. In this paper, we show the public key replacement attack on two certificateless blind signature schemes which are recently proposed in the literature. As a result, any one can generate a signature on any message by replacing the public key of a target user.