常用的四种加密解密算法。移位密码、仿射密码、维吉尼亚密码以及置换密码，用纯C语言编写。-four commonly used encryption and decryption algorithms. Shift password, affine password, Virginia and password replacement passwords, using pure C language.

常用的四种加密解密算法。移位密码、仿射密码、维吉尼亚密码以及置换密码，用纯C语言编写。-four commonly used encryption and decryption algorithms. Shift password, affine password, Virginia and password replacement passwords, using pure C language.