New Key Encapsulation Mechanism Scheme with Provable Security in the Standard Model

Abstract

Based on a newly introduced intractable problem named d-decisional Diffie-Hellman (d-DDH) problem, a new Key Encapsulation Mechanism (KEM) scheme is proposed. The scheme is proved secure against adaptively chosen ciphertext attacks in the standard model under the d-DDH assumption. And it is as efficient as those based on Decisional Diffie-Hellman Problem (DDHP), while it is based on the more hard d-DDH problem. Moreover, one can select different d for different security demand of applications. Compared with the schemes based on computational Diffie-Hellman problem, the efficiency of our scheme has obvious advantage.