加密：

//加密，docPath:要加密的文件路径，strKey:秘钥public static void Encrypt(string docPath, string strKey){    //分组加密算法    var fs = new FileStream(docPath, FileMode.Open);    byte[] buffer = new byte[fs.Length];    fs.Read(buffer, 0, buffer.Length);//得到需要加密的字节数组        //设置密钥,密钥向量，两个一样，都是16个byte    var rDel = new RijndaelManaged();    var key = Encoding.UTF8.GetBytes(strKey);    rDel.Key = key;    rDel.Mode = CipherMode.ECB;    rDel.Padding = PaddingMode.PKCS7;    ICryptoTransform cTransform = rDel.CreateEncryptor();    byte[] cipherBytes = cTransform.TransformFinalBlock(buffer, 0, buffer.Length);    var fsEncrypt = new FileStream(docPath + "ENC", FileMode.Create, FileAccess.Write);    fsEncrypt.Write(cipherBytes, 0, cipherBytes.Length);    fsEncrypt.Close();    fsEncrypt.Dispose();    fs.Close();    fs.Dispose();}

解密：

//解密，fileIn:解密的文件路径，fileOut:解密后的文件存放路径,strKey:秘钥public static void Decrypt(string fileIn, string fileOut, string strKey){    var fsIn = new FileStream(fileIn, FileMode.Open, FileAccess.Read);    var fsOut = new FileStream(fileOut, FileMode.OpenOrCreate, FileAccess.Write);    var rDel = new RijndaelManaged();    var key = Encoding.UTF8.GetBytes(strKey);    rDel.Key = key;    rDel.Mode = CipherMode.ECB;    rDel.Padding = PaddingMode.PKCS7;    var cs = new CryptoStream(fsOut, rDel.CreateDecryptor(), CryptoStreamMode.Write);    var bufferLen = 4096;    var buffer = new byte[bufferLen];    int bytesRead;    do    {        bytesRead = fsIn.Read(buffer, 0, bufferLen);        cs.Write(buffer, 0, bytesRead);    } while (bytesRead != 0);    cs.Close();    fsIn.Close();    fsIn.Dispose();    fsOut.Dispose();}