我们知道,建立在字母移位、置换替代等方法基础上,以密表、密本为主体的古典密码,经过信息论专家仙农的判析,无论哪种语言体系,由于受字母频度、熵值和冗余度等参数的制约,都是比较容易破译的,这类加密算法是较脆弱的(参看古典密码有关的内容和问题)。而像1929年美国数学家莱斯特·希尔提出的基于线性方程组的加密算法 We know that based on the letter shift, replacement and other methods, based on the dense form, the secret of the classical password as the main body, through information theory experts Xiannon analysis, no matter what language system, due to the letter frequency, entropy Values ​​and redundancy constraints and other parameters are relatively easy to decipher this type of encryption algorithm is more vulnerable (see the classical password-related content and issues). And as the 1929 American mathematician Lester Hill proposed linear equations based on the encryption algorithm