net CRC16校验

1、CRC16校验

   // CRC16效验
        public string CalcCRC16(string strInput)
        {
            ushort crc = 0xffff;
            ushort x;
            byte[] data = GetBytesFromHexString(strInput);
            for (int i = 0; i < data.Length; i++)
            {
                crc ^= (ushort)(data[i] << 8);
                for (int j = 0; j < 8; j++)
                {
                    if ((crc & 1) > 0)
                        crc = (ushort)((crc >> 1) ^ 0xA001);
                    else
                        crc >>= 1;
                }
            }

            x = (byte)(crc >> 8);  //高位置
            crc = (byte)(crc << 8);
            crc = (byte)(crc + x);
            return crc.ToString("X4");
        }

        // byte
        public Byte[] GetBytesFromHexString(string strInput)
        {
            Byte[] bytArOutput = new Byte[] { };
            if (!string.IsNullOrEmpty(strInput) && strInput.Length % 2 == 0)
            {
                SoapHexBinary hexBinary = null;
                try
                {
                    hexBinary = SoapHexBinary.Parse(strInput);
                    if (hexBinary != null)
                    {
                        bytArOutput = hexBinary.Value;
                    }
                }
                catch (Exception ex)
                {
                    Response.Write(ex.Message);
                }
            }
            return bytArOutput;
        }

        /// 

        /// 
        /// 
        /// 
        /// 
        /// 
        public static string ToCRC16(string content, Encoding encoding)
        {
            return ByteToString(CRC16(encoding.GetBytes(content)), true);
        }

        public static string ByteToString(byte[] arr, bool isReverse)
        {
            try
            {
                byte hi = arr[0], lo = arr[1];
                return Convert.ToString(isReverse ? hi + lo * 0x100 : hi * 0x100 + lo, 16).ToUpper().PadLeft(4, '0');
            }
            catch (Exception ex) { throw (ex); }
        }

        public static byte[] CRC16(byte[] data)
        {
            int len = data.Length;
            if (len > 0)
            {
                ushort crc = 0xFFFF;

                for (int i = 0; i < len; i++)
                {
                    crc = (ushort)(crc ^ (data[i]));
                    for (int j = 0; j < 8; j++)
                    {
                        crc = (crc & 1) != 0 ? (ushort)((crc >> 1) ^ 0xA001) : (ushort)(crc >> 1);
                    }
                }
                byte hi = (byte)((crc & 0xFF00) >> 8);  //高位置
                byte lo = (byte)(crc & 0x00FF);         //低位置

                return new byte[] { hi, lo };
            }
            return new byte[] { 0, 0 };
        }

https://www.cnblogs.com/mr-hu2009/p/10500017.html