Efficient Identity-Based Offline/Online Encryption Scheme for Lightweight Devices

摘要

Encryption scheme using heavy computations and large amounts of computing resources is not applicable for lightweight devices, due to the limited storage and power. The technique of offline/online is a possible way to solve this dilemma. Based on bilinear pairing on elliptic curves, a novel identity-based offline/online encryption scheme for lightweight devices is proposed. In the offline encryption phase, point multiplication and other heavy computations are preprocessed by powerful devices. Only light computations are needed in the online encryption phase, which is suitable for lightweight devices and accelerates the encryption speed. Formal security analysis indicates that the proposed scheme is IND-ID-CCA2 secure under the k-BCAA2 assumption. Compared to other related schemes, our scheme has less offline storage and shorter ciphertext, and achieves better performance in both encryption and decryption phase.