中文摘要：

前向安全公钥加密方案是指当前时段的私钥泄露不会造成敌手得到解密过去时段的密文的能力。已有的前向安全加密方案一般存在密文长度与时间段总数成线性关系的问题,并且加解密效率也较低。针对这一系列问题,提出了一个新的前向安全公钥加密方案,所有参数关于时间段总数的复杂性均不超过对数的平方,且在标准模型下证明了它的安全性。该方案具有定长密文、固定加/解密开销的特点。

英文摘要：

Forward-secure public-key encryption is that even if an adversary learns the secret key for some time period i,it still has no ability to decrypt the ciphertext during all time periods prior to i. The existed forward-secure public-key encryption schemes had a linear relationship between ciphertxt length and time periods,and low decryption efficiency. This paper proposed a new forward-secure public-key encryption scheme to resolved these questions. All the parameters in this scheme had at most a log-squared complexity in terms of the total number of time periods,and the proposed scheme was proven to be secure in the standard model. This scheme has constant ciphertext length and encryption /decryption.