纯C语言实现基于AES算法的解密功能，从用AES加密后的文件读取16个字节后，解密操作，同时读取加密文件的前四个字节，表示源文件的长度大小。-Pure C language implementation based on AES algorithm decryption functions, read 16 bytes from the file after using AES encryption and decryption operations, read the first four b