改进的CBC模式及其安全性分析

Improved CBC mode of operation and its security analysis

针对CBC模式在分块适应性攻击模型下不安全这一问题,提出了一个新的分组密码工作模式。新方案引进了Gray码,改变了原有模式的输入方式,打乱了前后输出输入的内在联系。同时,利用规约的思想对其安全性进行了分析。结果表明,在所用分组密码是伪随机置换的条件下,方案在分块适应性攻击模型下是可证明安全的。

A novel scheme of block-cipher mode of operation was proposed to solve the secure problem under the blockwise adaptive attack model. The Gray code was introduced to improve the input manner and disturb the intrinsic relation of input and output data. The security of the scheme was analyzed in the reduction-based cryptography. Investigation shows that the scheme is provable security under the blockwise adaptive attack model if the underlying block cipher is a pseudorandom permutation.