Is there any difference in calculating CRC32 checksum in C# and Java?

Question

I have to calculate CRC32 checksum for a string in C# and send it to an external application.

On the other end they will calculate it using Java.

But my checksum does not match on the their end.

e.g. CRC32 checksum of the following string 43HLV109520DAP10072la19z6

is 1269993351 on their end.

And 2947932745 at my end using C#

Please tell me what's going wrong in my code.

I am using this 0xffffffff default seed and following crc table

readonly static uint[] CRCTable = new uint[] {
            0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419,
            0x706AF48F, 0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4,
            0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07,
            0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
            0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856,
            0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9,
            0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4,
            0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
            0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3,
            0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC, 0x51DE003A,
            0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599,
            0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
            0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190,
            0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F,
            0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E,
            0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
            0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED,
            0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
            0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3,
            0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
            0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A,
            0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5,
            0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA, 0xBE0B1010,
            0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
            0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17,
            0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6,
            0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615,
            0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
            0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344,
            0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
            0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A,
            0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
            0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1,
            0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C,
            0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF,
            0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
            0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE,
            0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31,
            0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C,
            0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
            0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B,
            0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
            0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1,
            0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
            0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278,
            0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7,
            0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66,
            0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
            0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605,
            0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8,
            0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B,
            0x2D02EF8D
        };

Answer 1

CRC32 is calculated over a sequence of bytes and not over a string. So to calculate CRC32 you need to transform the string into bytes first. If you use a different encoding to transform a string to a sequence of bytes the result will be different.

Thus you need to use the same encoding on both sides. I recommend using UTF-8 without BOM.

Answer 2

I have calculated CRC32 with Java and got the same you got in C#. I.e. CRC32(43HLV109520DAP10072la19z6)=2947932745. This means that either they have a bug in java, or you have a bug during transmission.

Code follows.

I suggest you try to send simple data to java application, like zeros or ones, and try to deduce how do they compute CRC.

public static void main(String[] args) {

    CRC32 crc32 = new CRC32();

    String data = "43HLV109520DAP10072la19z6";

    String[] cs = new String[] {"utf8" /*, "cp1252", "cp866" */};
    byte[] array;
    byte b;

    for(int i=0; i<cs.length; ++i) {

        array = data.getBytes(Charset.forName(cs[i]));

        crc32.reset();
        crc32.update(array);

        System.out.println(String.format("%s: %d", cs[i], crc32.getValue()));

        /*
        for(int j=0; j<array.length/2; j++) {
            b = array[i];
            array[i] = array[array.length-1-i];
            array[array.length-1-i] = b;
        }
        */

        for(int j=0; j<array.length; j+=2) {
            b = array[i];
            array[i] = array[i+2];
            array[i+1] = b;
        }

        crc32.reset();
        crc32.update(array);

        System.out.println(String.format("of modified: %d", crc32.getValue()));
    }




}

UPDATE

Endiannes reverse also not help

        for(int j=0; j<array.length; j+=4) {

            b = array[i];
            array[i] = array[i+3];
            array[i+3] = b;


            b = array[i+1];
            array[i+1] = array[i+2];
            array[i+2] = b;
        }

Answer 3

Without delving into any detail, the problem can be related to Java's lack of unsigned integer types. The problem could happen at the int level, but also at the byte level. This is one avenue of investigation.