Question

我正在尝试将串行端口设备集成到我的应用程序中，这需要对我发送给它的字节进行CRC-CCTT验证。我是管理字节数据包的新手，并且需要帮助。

它使用此公式进行CRC演算：

[CRC-CCITT P(X)= X16 + C12 + C8 + 1]

因此，例如对于数据包：0xFC 0x05 0x11，CRC为0x5627。然后我将此数据包发送到设备：0xFC 0x05 0x11 0x27 0x56

此外，数据包长度将在5到255之间变化（包括CRC校验字节）

我不知道如何实现这一点，所以欢迎任何想法/建议。

希望我说清楚，在此先感谢。

编辑：这是我需要做的规范：

enter image description here

Answer 1

标准crc-ccitt是x16 + x12 + x5 + 1我写了一个@ http://www.sanity-free.com/133/crc_16_ccitt_in_csharp.html如果我有时间我会看到我是否无法修改它以运行x16 + x12 + x8 + 1 poly。

编辑：

你去：

public class Crc16CcittKermit {
    private static ushort[] table = {
      0x0000, 0x1189, 0x2312, 0x329B, 0x4624, 0x57AD, 0x6536, 0x74BF,
      0x8C48, 0x9DC1, 0xAF5A, 0xBED3, 0xCA6C, 0xDBE5, 0xE97E, 0xF8F7,
      0x1081, 0x0108, 0x3393, 0x221A, 0x56A5, 0x472C, 0x75B7, 0x643E,
      0x9CC9, 0x8D40, 0xBFDB, 0xAE52, 0xDAED, 0xCB64, 0xF9FF, 0xE876,
      0x2102, 0x308B, 0x0210, 0x1399, 0x6726, 0x76AF, 0x4434, 0x55BD,
      0xAD4A, 0xBCC3, 0x8E58, 0x9FD1, 0xEB6E, 0xFAE7, 0xC87C, 0xD9F5,
      0x3183, 0x200A, 0x1291, 0x0318, 0x77A7, 0x662E, 0x54B5, 0x453C,
      0xBDCB, 0xAC42, 0x9ED9, 0x8F50, 0xFBEF, 0xEA66, 0xD8FD, 0xC974,
      0x4204, 0x538D, 0x6116, 0x709F, 0x0420, 0x15A9, 0x2732, 0x36BB,
      0xCE4C, 0xDFC5, 0xED5E, 0xFCD7, 0x8868, 0x99E1, 0xAB7A, 0xBAF3,
      0x5285, 0x430C, 0x7197, 0x601E, 0x14A1, 0x0528, 0x37B3, 0x263A,
      0xDECD, 0xCF44, 0xFDDF, 0xEC56, 0x98E9, 0x8960, 0xBBFB, 0xAA72,
      0x6306, 0x728F, 0x4014, 0x519D, 0x2522, 0x34AB, 0x0630, 0x17B9,
      0xEF4E, 0xFEC7, 0xCC5C, 0xDDD5, 0xA96A, 0xB8E3, 0x8A78, 0x9BF1,
      0x7387, 0x620E, 0x5095, 0x411C, 0x35A3, 0x242A, 0x16B1, 0x0738,
      0xFFCF, 0xEE46, 0xDCDD, 0xCD54, 0xB9EB, 0xA862, 0x9AF9, 0x8B70,
      0x8408, 0x9581, 0xA71A, 0xB693, 0xC22C, 0xD3A5, 0xE13E, 0xF0B7,
      0x0840, 0x19C9, 0x2B52, 0x3ADB, 0x4E64, 0x5FED, 0x6D76, 0x7CFF,
      0x9489, 0x8500, 0xB79B, 0xA612, 0xD2AD, 0xC324, 0xF1BF, 0xE036,
      0x18C1, 0x0948, 0x3BD3, 0x2A5A, 0x5EE5, 0x4F6C, 0x7DF7, 0x6C7E,
      0xA50A, 0xB483, 0x8618, 0x9791, 0xE32E, 0xF2A7, 0xC03C, 0xD1B5,
      0x2942, 0x38CB, 0x0A50, 0x1BD9, 0x6F66, 0x7EEF, 0x4C74, 0x5DFD,
      0xB58B, 0xA402, 0x9699, 0x8710, 0xF3AF, 0xE226, 0xD0BD, 0xC134,
      0x39C3, 0x284A, 0x1AD1, 0x0B58, 0x7FE7, 0x6E6E, 0x5CF5, 0x4D7C,
      0xC60C, 0xD785, 0xE51E, 0xF497, 0x8028, 0x91A1, 0xA33A, 0xB2B3,
      0x4A44, 0x5BCD, 0x6956, 0x78DF, 0x0C60, 0x1DE9, 0x2F72, 0x3EFB,
      0xD68D, 0xC704, 0xF59F, 0xE416, 0x90A9, 0x8120, 0xB3BB, 0xA232,
      0x5AC5, 0x4B4C, 0x79D7, 0x685E, 0x1CE1, 0x0D68, 0x3FF3, 0x2E7A,
      0xE70E, 0xF687, 0xC41C, 0xD595, 0xA12A, 0xB0A3, 0x8238, 0x93B1,
      0x6B46, 0x7ACF, 0x4854, 0x59DD, 0x2D62, 0x3CEB, 0x0E70, 0x1FF9,
      0xF78F, 0xE606, 0xD49D, 0xC514, 0xB1AB, 0xA022, 0x92B9, 0x8330,
      0x7BC7, 0x6A4E, 0x58D5, 0x495C, 0x3DE3, 0x2C6A, 0x1EF1, 0x0F78
    };

    public static ushort ComputeChecksum( params byte[] buffer ) {
        if ( buffer == null ) throw new ArgumentNullException( );
        ushort crc = 0;
        for ( int i = 0; i < buffer.Length; ++i ) {
            crc = (ushort)( ( crc >> 8 ) ^ table[( crc ^ buffer[i] ) & 0xff] );
        }
        return crc;
    }

    public static byte[] ComputeChecksumBytes( params byte[] buffer ) {
        return BitConverter.GetBytes( ComputeChecksum( buffer ) );
    }
}

样品：

ushort crc = Crc16CcittKermit.ComputeChecksum( 0xFC, 0x05, 0x11 );
byte[] crcBuffer = Crc16CcittKermit.ComputeChecksumBytes( 0xFC, 0x05, 0x11 )
// crc = 0x5627
// crcBuffer = { 0x27, 0x56 }

Answer 2

您是否尝试使用Google搜索示例？其中有很多。

示例1：http://tomkaminski.com/crc32-hashalgorithm-c-net
示例2：http://www.sanity-free.com/12/crc32_implementation_in_csharp.html

您还可以通过System.Security.Cryptography.MD5CryptoServiceProvider在.Net中获得原生MD5支持。

编辑：

如果您正在寻找一个8位算法：http://www.codeproject.com/KB/cs/csRedundancyChckAlgorithm.aspx
和16位：http://www.sanity-free.com/133/crc_16_ccitt_in_csharp.html

Answer 3

大声笑，我遇到了完全相同的STATUS REQUEST序列，我正在开发与CashCode Bill Validator一起使用的软件:)。这是代码对我有用，它是CRC16-CCITT，反向多项式等于0x8408（代码中的BDPConstants.Polynomial）。那段代码对我有用：

    // TableCRC16Size is 256 of course, don't forget to set in somewhere
    protected ushort[] TableCRC16 = new ushort[BDPConstants.TableCRC16Size];
    protected void InitCRC16Table()
    {
        for (ushort i = 0; i < BDPConstants.TableCRC16Size; ++i)
        {
            ushort CRC = 0;
            ushort c = i;
            for (int j = 0; j < 8; ++j)
            {
                if (((CRC ^ c) & 0x0001) > 0)
                    CRC = (ushort)((CRC >> 1) ^ BDPConstants.Polynominal);
                else
                    CRC = (ushort)(CRC >> 1);
                c = (ushort)(c >> 1);
            }
            TableCRC16[i] = CRC;
        }
    }

    protected ushort CalcCRC16(byte[] aData)
    {
        ushort CRC = 0;
        for (int i = 0; i < aData.Length; ++i)
            CRC = (ushort)(TableCRC16[(CRC ^ aData[i]) & 0xFF] ^ (CRC >> 8));
        return CRC;
    }

在某处初始化表格（例如表格构造函数）：

InitCRC16Table();

然后在你的代码中使用它，就像那样，

您可以使用字节列表而不是数组，更方便在“数据包”中打包字节数据进行发送

uint CRC = CalcCRC16(byte[] aByte)
// You need to split your CRC in two bytes of course
byte CRCHW = (byte)((CRC) / 256); // that's your 0x56
byte CRCLW = (byte)(CRC);         // that's your 0x27

Answer 4

它有效并且不需要表格：

    /// <summary>
    /// Gens the CRC16.
    /// CRC-1021 = X(16)+x(12)+x(5)+1
    /// </summary>
    /// <param name="c">The c.</param>
    /// <param name="nByte">The n byte.</param>
    /// <returns>System.Byte[][].</returns>
    public ushort GenCrc16(byte[] c, int nByte)
    {
        ushort Polynominal = 0x1021;
        ushort InitValue = 0x0;

        ushort i, j, index = 0;
        ushort CRC = InitValue;
        ushort Remainder, tmp, short_c;
        for (i = 0; i < nByte; i++)
        {
            short_c = (ushort)(0x00ff & (ushort) c[index]);
            tmp = (ushort)((CRC >> 8) ^ short_c);
            Remainder = (ushort)(tmp << 8);
            for (j = 0; j < 8; j++)
            {

                if ((Remainder & 0x8000) != 0)
                {
                    Remainder = (ushort)((Remainder << 1) ^ Polynominal);
                }
                else
                {
                    Remainder = (ushort)(Remainder << 1);
                }
            }
            CRC = (ushort)((CRC << 8) ^ Remainder);
            index++;
        }
        return CRC;
    }

Answer 5

您实际上正在使用CRC-XMODEM LSB-reverse（具有0x8408系数）。这个演算的C＃代码是：

public void crc_bytes(int[] int_input)
{    
   int_array = int_input;
   int int_crc = 0x0; // or 0xFFFF;

   int int_lsb;
   for (int int_i = 0; int_i < int_array.Length; int_i++)
   {
      int_crc = int_crc ^ int_array[int_i];
      for (int int_j = 0; int_j < 8; int_j ++ )
      {
         int_lsb = int_crc & 0x0001; // Mask of LSB
         int_crc = int_crc >> 1;
         int_crc = int_crc & 0x7FFF;
         if (int_lsb == 1)
            int_crc = int_crc ^ 0x8408;
      }
   }

   int_crc_byte_a = int_crc & 0x00FF;
   int_crc_byte_b = (int_crc >> 8) & 0x00FF;
}

阅读更多（或下载项目）：

http://www.cirvirlab.com/index.php/c-sharp-code-examples/141-c-sharp-crc-computation.html

C＃CRC实现

5 个答案: