标准模型下KDM安全的对称加密方案

摘要

Key-Dependent Message (KDM) security was introduced to address the case where message is a function of secret key of encryption scheme. By using universal hash function, this paper presents a stateless symmetric encryption scheme that is information-theoretically KDM secure based on an extended version of left-over hash lemma in the standard model. The scheme is secure in face of a bounded of nearly exponent number of encryptions for which the messages depend in an arbitrary way on the secret key. Finally, through choosing parameters properly and comparing with existing schemes, the security and efficiency of the constructed scheme are proved to be improved.%KDM(Key-Dependent Message)安全是考虑当加密的明文消息是所用加密方案私钥的函数时的安全问题.该文利用通用哈希函数(universal hash function),在标准模型下基于一种变形的剩余哈希引理(left-over hashlemma)构造出一个信息论KDM安全的无状态对称加密方案.该方案能够抵抗任意攻击者接近指数次边界的KDM加密询问攻击,并且攻击者询问的挑战函数可以是任意集合.最后通过合理选择参数,对比已有方案,证明该文所构造方案的安全性有所提高.