关键词: 公钥加密, 标准模型, 可证明安全性, 适应性选择密文攻击, 语义安全性, d-判定性Diffie-Hellman问题

Abstract: The public key encryption schemes with semantic security against adaptively chosen cipertext attacks in the standard model suffer from the drawbacks of low efficiency or strong computational assumptions. Concerning these problems, a new provable secure public key encryption scheme was proposed based on the newly introduced d-decisional Diffie-Hellman problem. To obtain the security and efficiency, the methodology of Hash proof system was adopted in the construction and security proof of the scheme. The intractability of the d-decisional Diffie-Hellman problem was between that of the computational Diffie-Hellman problem and decisional Diffie-Hellman problem. The efficiency of the scheme surpassed that of the schemes based on the computational Diffie-Hellman problem and approximated with the schemes based on the decisional Diffie-Hellman problem. Therefore, the proposed scheme has reached a good compromise between efficiency and computational assumption. Moreover, it can select different d for different security demand of applications.

Key words: Public Key Encryption (PKE), standard model, provable security, adaptively chosen ciphertext attack, semantic security, d-decisional Diffie-Hellman problem