International Association
for Cryptologic Research

Implicit certificates own the shorter public key validation data. This property makes them appealing in resource-constrained IoT systems where public key validation is performed very often, which is common in Host Identity Protocol (HIP). However, it is still a critical challenge in IoT how to guarantee the security and efficiency of implicit certificates. This article presents a forgery attack for the Privacy-aware HIP (P-HIP), and then propose a Secure and Efficient Implicit Certificate (SEIC) scheme that can improve the security of the P-HIP and the efficiency of elliptic-curve point multiplications for IoT devices. For a fix-point multiplication, the proposed approach is about 1:5 times faster than the method in SIMPL scheme. Furthermore, we improve the performance of SEIC with the butterfly key expansion process, and then construct an improved P-HIP. Experimental results show that the improved P-HIP can achieve the performance gains.