//由包头至有效数据生成CRC与收上来的数据CRC进行比较
private static bool IsCRCOK(User user, byte[] receive)
{
//第二步 由包头至有效数据生成CRC与收上来的数据CRC进行比较
user.checkCRC = 0; //crc校验码清零 很重要
//由收上来的数据生成CRC检验码
for (int i = 0; i < (receive.Length - 6); i++) //CRC校验
{
user.checkCRC = CRCtest.CRC(receive[i], user.checkCRC);
}
//CRC校验 receive[receive.Length - 6]CRC高位 receive[receive.Length - 5]CRC低位
if ((receive[receive.Length - 6] == (byte)(user.checkCRC >> 8)) && ((byte)user.checkCRC == receive[receive.Length - 5]))
{
return(true);
}
else
{
return(false);
}
}
/// <summary>
/// 加密封包函数（包含CRC校验）
/// </summary>
///// <param name="user">对象</param>
/// <param name="message">要进行封包的有效数据字符串（未进行加密）</param>
/// <returns></returns>
public static byte[] PacketMessage(User user, string message)
{
try
{
string path = "keyInfo.xml";
XmlDocument xd = new XmlDocument();
xd.Load(path);
XmlNode root = xd.DocumentElement;
byte[] key = Encoding.ASCII.GetBytes(root.SelectSingleNode("key").InnerText); //获得AES密钥
byte[] IV = Encoding.ASCII.GetBytes(root.SelectSingleNode("IV").InnerText); //获得AES初始量
// 1 对xml指令进行AES加密 形成有效数据
// byte[] key = Encoding.ASCII.GetBytes(GlobalInfo.Key);//获得AES密钥
//byte[] IV = Encoding.ASCII.GetBytes(GlobalInfo.IV);//获得AES初始量
byte[] crypted = AES.AEScryptedDataToByte(message, key, IV);//加密后的XML文本内容
//byte[] crypted = aes.AEScryptedDataToByte("1234567890123456", key, IV);
//byte[] crypted = Encoding.ASCII.GetBytes(message);
int count = crypted.Length + 4;//加上四个字节的指令序号 这部分构成有限数据
//2 封包
//计算有效数据长度（高位在前（command[6]））
//经过计算，两个字节可以代表的最大（FFFF）65536个字节约为64k 对于发送的数据长度来说足够了
//user.command[4] = 0x00;
//user.command[5] = 0x00;
//user.command[6] = Convert.ToByte((int)count / 256);//有效数据除以256取整 高位字节的大小
//user.command[7] = Convert.ToByte(count - ((int)count / 256) * 256);//总长度-高位字节的大小=剩余的字节数（由低位字节表示）
switch (count.ToString().Length)
{
case 0:
user.command[4] = 0x30;
user.command[5] = 0x30;
user.command[6] = 0x30;
user.command[7] = 0x30;
break;
case 1:
user.command[4] = 0x30;
user.command[5] = 0x30;
user.command[6] = 0x30;
user.command[7] = Convert.ToByte(count + 30);
break;
case 2:
user.command[4] = 0x30;
user.command[5] = 0x30;
user.command[6] = Convert.ToByte(int.Parse(count.ToString().Substring(0, 1)) + 48);
user.command[7] = Convert.ToByte(int.Parse(count.ToString().Substring(1, 1)) + 48);
break;
case 3:
user.command[4] = 0x30;
user.command[5] = Convert.ToByte(int.Parse(count.ToString().Substring(0, 1)) + 48);
user.command[6] = Convert.ToByte(int.Parse(count.ToString().Substring(1, 1)) + 48);
user.command[7] = Convert.ToByte(int.Parse(count.ToString().Substring(2, 1)) + 48);
break;
case 4:
user.command[4] = Convert.ToByte(int.Parse(count.ToString().Substring(0, 1)) + 48);
user.command[5] = Convert.ToByte(int.Parse(count.ToString().Substring(1, 1)) + 48);
user.command[6] = Convert.ToByte(int.Parse(count.ToString().Substring(2, 1)) + 48);
user.command[7] = Convert.ToByte(int.Parse(count.ToString().Substring(3, 1)) + 48);
break;
default:
break;
}
//指令序号(四个字节)
user.command[8] = 0x30; //指令序号
user.command[9] = 0x30; //指令序号
user.command[10] = 0x30; //指令序号
user.command[11] = 0x30; //指令序号
//将有效数据写入command指令
for (int i = 0; i < (count - 4); i++)//command[8+count]是第一位CRC校验 count中包含4个字节的指令序号
{
user.command[12 + i] = crypted[i];
}
//3 生成CRC校验码 由包头至有效数据部分生成
user.checkCRC = 0; //crc校验码清零 很重要
for (int i = 0; i < (count + 8); i++) //CRC校验
{
user.checkCRC = CRCtest.CRC(user.command[i], user.checkCRC);
}
user.command[8 + count] = (byte)(user.checkCRC >> 8); //CRC高位
user.command[9 + count] = (byte)user.checkCRC; //CRC低位
//包尾
user.command[10 + count] = 0x55;
user.command[11 + count] = 0xAA;
user.command[12 + count] = 0x55;
user.command[13 + count] = 0xAA;
//4 截取command的有效数据（去掉未赋值的空字节）
byte[] command_Result = new byte[14 + count];
for (int i = 0; i <= (13 + count); i++)
{
command_Result[i] = user.command[i];
}
return(command_Result);//返回具有一定长度的字节数组（即发送指令）
}
catch
{ return(null); }
}