标准模型下前向安全公钥加密方案的新构造

针对已有的可证安全的前向安全公钥加密方案仅满足较弱的选择明文安全性，难以满足实际应用的安全需求这一问题，提出了一个新的前向安全公钥加密方案，基于判定性截断q-ABDHE问题的困难性，该方案在标准模型下被证明满足选择密文安全性。在该方案中，解密算法的计算代价和密文的长度独立于系统时间周期总数。对比分析表明，该方案的整体性能优于已有的前向安全公钥加密方案。

Novel construction of forward-secure public-keyencryption in the standard model

All existing provably secure forward-secure public-key encryption schemes in the literature were only proven to be chosen-plaintext secure. A novel forward-secure public-key encryption scheme without random oracles was proposed. Under the hardness of the truncated decision q-augmented bilinear Diffie-Hellman exponent problem, the proposed scheme was proved to be chosen-ciphertext secure in the standard model. In the proposed scheme, the running time of decryption algorithm and the size of ciphertext are both independent on the total number of the time periods. Compared with the previous forward-secure public-key encryption schemes in the literature, the proposed scheme has obvious advantage in security and efficiency.