WIST:基于三维查找表的SM4算法新型白盒设计

WIST: White-Box Implementation of SM4 Algorithm with Three-Dimensional Lookup Table

随着密码攻击方式更加多样、隐蔽且破坏性更强,密码分析者可能拥有越来越多的攻击权限与攻击能力,甚至能够获取算法的内部结构.为了更有效保护密钥,本文提出一种基于三维查找表的白盒SM4密码算法实现方案WIST.首先将SM4分组密码算法的线性变换用矩阵表示,设计了能对密钥信息进行隐藏保护的三维查找表,利用输入编码和输出编码对查找表混淆处理,同时采用仿射函数作为外部编码,完成了SM4算法的白盒化实现,并验证了此算法的正确性.效率分析表明WIST占用内存空间适中,具有较高安全性;安全性分析表明WIST能抵抗BGE攻击、MGH攻击、侧信道攻击、线性攻击与差分攻击等常见攻击类型.WIST可以在白盒攻击环境下更好地保护密钥信息.

As cryptographic attacks become more diverse,covert and destructive,cryptanalysts are assumed to have more power and capabilities than before,and are able to obtain the internal structure of the target cryptographic algorithms. In order to protect keys more effectively, a novelwhite-box implementation for SM4 algorithm is proposed based on three-dimensional lookup table,called WIST in this paper. The SM4 block cipher algorithm is expressed in nonsingular matrix oflinear transformation;then the three-dimensional lookup table is designed to hide the key information,the input coding and output coding are used to confuse the lookup table. Meanwhile, the affine functionis adopted as external coding, the white-box implementation for SM4 algorithm is completed, and thecorrectness of this algorithm is also verified. The efficiency analysis on WIST algorithm shows thatit occupies moderate memory space and has high security. The security analysis on WIST algorithmshows that this scheme can resist BGE attack, MGH attack, side channel attack, linear attack anddifferential attack. This scheme can protect key information well in white-box attack environment.