On the Security of a Pairing-Based Signcryption Scheme using Self-Certified Public Keys

Abstract

Signcryption is a cryptographic primitive that performs digital signature and public key encryption simultaneously at lower computational costs and communication overheads than the signature-then-encryption approach. To overcome the drawback of key escrow in the identity-based signcryption, Li, Xin, and Hu proposed a pairing-based signcryption scheme using self-certified public keys recently. In this article, the authors show that the Li–Xin–Hu scheme does not satisfy the security requirement of self-certified public keys. To be more precise, a malicious private key generator (PKG) can impersonate an honest user without being detected.