No CRC64 implementation equal to CommonCrypto?

Question

I am porting some code from C on OSX to C# that uses CommonCrypto with the kCN_CRC_64_ECMA_182 CRC64 implementation. For example, using CommonCrypto the CRC would be computed with:

CNCRC(kCN_CRC_64_ECMA_182, bytes, bytesLen, &crcResult)

This outputs the correct value. When using the C# library HashLib (or any other code), the output is completely different, for example, the equivalent to the above using HashLib would be:

var checksum = HashFactory.Checksum.CreateCRC64(0x42F0E1EBA9EA3693UL); // ECMA 182 var result = checksum.ComputeBytes(bytes);

Any ideas? Is there an implementation in C# that is equivalent to Apple's CommonCrypto in terms of output?

Answer 1

Here is some simple C code to compute the ECMA-182 CRC:

#include <stddef.h>
#include <stdint.h>

#define POLY UINT64_C(0x42f0e1eba9ea3693)
#define TOP UINT64_C(0x8000000000000000)

/* Return crc updated with buf[0..len-1].  If buf is NULL, return the initial
   crc.  So, initialize with crc = crc64_ecma182(0, NULL, 0); and follow with
   one or more applications of crc = crc64_ecma182(crc, buf, len); */
int64_t crc64_ecma182(int64_t crc, unsigned char *buf, size_t len)
{
    int k;

    if (buf == NULL)
        return 0;
    while (len--) {
        crc ^= (uint64_t)(*buf++) << 56;
        for (k = 0; k < 8; k++)
            crc = crc & TOP ? (crc << 1) ^ POLY : crc << 1;
    }
    return crc;
}

I think HashLib is simply wrong, judging by what I found on github. It is doing the CRC reflected, whereas the CRC64 defined in ECMA-182 is not reflected.

Answer 2

To spare you all the endless search for a working CRC64 algorithm that returns the correct result, while in reality only finding unreadable code and god-object implementations which still yield the wrong result...

Here is the basic algorithm.

private static readonly ulong[] Crc64Table =
{
    0x0000000000000000, 0x42f0e1eba9ea3693, 0x85e1c3d753d46d26, 0xc711223cfa3e5bb5, 0x493366450e42ecdf, 0x0bc387aea7a8da4c, 0xccd2a5925d9681f9, 0x8e224479f47cb76a,
    0x9266cc8a1c85d9be, 0xd0962d61b56fef2d, 0x17870f5d4f51b498, 0x5577eeb6e6bb820b, 0xdb55aacf12c73561, 0x99a54b24bb2d03f2, 0x5eb4691841135847, 0x1c4488f3e8f96ed4,
    0x663d78ff90e185ef, 0x24cd9914390bb37c, 0xe3dcbb28c335e8c9, 0xa12c5ac36adfde5a, 0x2f0e1eba9ea36930, 0x6dfeff5137495fa3, 0xaaefdd6dcd770416, 0xe81f3c86649d3285,
    0xf45bb4758c645c51, 0xb6ab559e258e6ac2, 0x71ba77a2dfb03177, 0x334a9649765a07e4, 0xbd68d2308226b08e, 0xff9833db2bcc861d, 0x388911e7d1f2dda8, 0x7a79f00c7818eb3b,
    0xcc7af1ff21c30bde, 0x8e8a101488293d4d, 0x499b3228721766f8, 0x0b6bd3c3dbfd506b, 0x854997ba2f81e701, 0xc7b97651866bd192, 0x00a8546d7c558a27, 0x4258b586d5bfbcb4,
    0x5e1c3d753d46d260, 0x1cecdc9e94ace4f3, 0xdbfdfea26e92bf46, 0x990d1f49c77889d5, 0x172f5b3033043ebf, 0x55dfbadb9aee082c, 0x92ce98e760d05399, 0xd03e790cc93a650a,
    0xaa478900b1228e31, 0xe8b768eb18c8b8a2, 0x2fa64ad7e2f6e317, 0x6d56ab3c4b1cd584, 0xe374ef45bf6062ee, 0xa1840eae168a547d, 0x66952c92ecb40fc8, 0x2465cd79455e395b,
    0x3821458aada7578f, 0x7ad1a461044d611c, 0xbdc0865dfe733aa9, 0xff3067b657990c3a, 0x711223cfa3e5bb50, 0x33e2c2240a0f8dc3, 0xf4f3e018f031d676, 0xb60301f359dbe0e5,
    0xda050215ea6c212f, 0x98f5e3fe438617bc, 0x5fe4c1c2b9b84c09, 0x1d14202910527a9a, 0x93366450e42ecdf0, 0xd1c685bb4dc4fb63, 0x16d7a787b7faa0d6, 0x5427466c1e109645,
    0x4863ce9ff6e9f891, 0x0a932f745f03ce02, 0xcd820d48a53d95b7, 0x8f72eca30cd7a324, 0x0150a8daf8ab144e, 0x43a04931514122dd, 0x84b16b0dab7f7968, 0xc6418ae602954ffb,
    0xbc387aea7a8da4c0, 0xfec89b01d3679253, 0x39d9b93d2959c9e6, 0x7b2958d680b3ff75, 0xf50b1caf74cf481f, 0xb7fbfd44dd257e8c, 0x70eadf78271b2539, 0x321a3e938ef113aa,
    0x2e5eb66066087d7e, 0x6cae578bcfe24bed, 0xabbf75b735dc1058, 0xe94f945c9c3626cb, 0x676dd025684a91a1, 0x259d31cec1a0a732, 0xe28c13f23b9efc87, 0xa07cf2199274ca14,
    0x167ff3eacbaf2af1, 0x548f120162451c62, 0x939e303d987b47d7, 0xd16ed1d631917144, 0x5f4c95afc5edc62e, 0x1dbc74446c07f0bd, 0xdaad56789639ab08, 0x985db7933fd39d9b,
    0x84193f60d72af34f, 0xc6e9de8b7ec0c5dc, 0x01f8fcb784fe9e69, 0x43081d5c2d14a8fa, 0xcd2a5925d9681f90, 0x8fdab8ce70822903, 0x48cb9af28abc72b6, 0x0a3b7b1923564425,
    0x70428b155b4eaf1e, 0x32b26afef2a4998d, 0xf5a348c2089ac238, 0xb753a929a170f4ab, 0x3971ed50550c43c1, 0x7b810cbbfce67552, 0xbc902e8706d82ee7, 0xfe60cf6caf321874,
    0xe224479f47cb76a0, 0xa0d4a674ee214033, 0x67c58448141f1b86, 0x253565a3bdf52d15, 0xab1721da49899a7f, 0xe9e7c031e063acec, 0x2ef6e20d1a5df759, 0x6c0603e6b3b7c1ca,
    0xf6fae5c07d3274cd, 0xb40a042bd4d8425e, 0x731b26172ee619eb, 0x31ebc7fc870c2f78, 0xbfc9838573709812, 0xfd39626eda9aae81, 0x3a28405220a4f534, 0x78d8a1b9894ec3a7,
    0x649c294a61b7ad73, 0x266cc8a1c85d9be0, 0xe17dea9d3263c055, 0xa38d0b769b89f6c6, 0x2daf4f0f6ff541ac, 0x6f5faee4c61f773f, 0xa84e8cd83c212c8a, 0xeabe6d3395cb1a19,
    0x90c79d3fedd3f122, 0xd2377cd44439c7b1, 0x15265ee8be079c04, 0x57d6bf0317edaa97, 0xd9f4fb7ae3911dfd, 0x9b041a914a7b2b6e, 0x5c1538adb04570db, 0x1ee5d94619af4648,
    0x02a151b5f156289c, 0x4051b05e58bc1e0f, 0x87409262a28245ba, 0xc5b073890b687329, 0x4b9237f0ff14c443, 0x0962d61b56fef2d0, 0xce73f427acc0a965, 0x8c8315cc052a9ff6,
    0x3a80143f5cf17f13, 0x7870f5d4f51b4980, 0xbf61d7e80f251235, 0xfd913603a6cf24a6, 0x73b3727a52b393cc, 0x31439391fb59a55f, 0xf652b1ad0167feea, 0xb4a25046a88dc879,
    0xa8e6d8b54074a6ad, 0xea16395ee99e903e, 0x2d071b6213a0cb8b, 0x6ff7fa89ba4afd18, 0xe1d5bef04e364a72, 0xa3255f1be7dc7ce1, 0x64347d271de22754, 0x26c49cccb40811c7,
    0x5cbd6cc0cc10fafc, 0x1e4d8d2b65facc6f, 0xd95caf179fc497da, 0x9bac4efc362ea149, 0x158e0a85c2521623, 0x577eeb6e6bb820b0, 0x906fc95291867b05, 0xd29f28b9386c4d96,
    0xcedba04ad0952342, 0x8c2b41a1797f15d1, 0x4b3a639d83414e64, 0x09ca82762aab78f7, 0x87e8c60fded7cf9d, 0xc51827e4773df90e, 0x020905d88d03a2bb, 0x40f9e43324e99428,
    0x2cffe7d5975e55e2, 0x6e0f063e3eb46371, 0xa91e2402c48a38c4, 0xebeec5e96d600e57, 0x65cc8190991cb93d, 0x273c607b30f68fae, 0xe02d4247cac8d41b, 0xa2dda3ac6322e288,
    0xbe992b5f8bdb8c5c, 0xfc69cab42231bacf, 0x3b78e888d80fe17a, 0x7988096371e5d7e9, 0xf7aa4d1a85996083, 0xb55aacf12c735610, 0x724b8ecdd64d0da5, 0x30bb6f267fa73b36,
    0x4ac29f2a07bfd00d, 0x08327ec1ae55e69e, 0xcf235cfd546bbd2b, 0x8dd3bd16fd818bb8, 0x03f1f96f09fd3cd2, 0x41011884a0170a41, 0x86103ab85a2951f4, 0xc4e0db53f3c36767,
    0xd8a453a01b3a09b3, 0x9a54b24bb2d03f20, 0x5d45907748ee6495, 0x1fb5719ce1045206, 0x919735e51578e56c, 0xd367d40ebc92d3ff, 0x1476f63246ac884a, 0x568617d9ef46bed9,
    0xe085162ab69d5e3c, 0xa275f7c11f7768af, 0x6564d5fde549331a, 0x279434164ca30589, 0xa9b6706fb8dfb2e3, 0xeb46918411358470, 0x2c57b3b8eb0bdfc5, 0x6ea7525342e1e956,
    0x72e3daa0aa188782, 0x30133b4b03f2b111, 0xf7021977f9cceaa4, 0xb5f2f89c5026dc37, 0x3bd0bce5a45a6b5d, 0x79205d0e0db05dce, 0xbe317f32f78e067b, 0xfcc19ed95e6430e8,
    0x86b86ed5267cdbd3, 0xc4488f3e8f96ed40, 0x0359ad0275a8b6f5, 0x41a94ce9dc428066, 0xcf8b0890283e370c, 0x8d7be97b81d4019f, 0x4a6acb477bea5a2a, 0x089a2aacd2006cb9,
    0x14dea25f3af9026d, 0x562e43b4931334fe, 0x913f6188692d6f4b, 0xd3cf8063c0c759d8, 0x5dedc41a34bbeeb2, 0x1f1d25f19d51d821, 0xd80c07cd676f8394, 0x9afce626ce85b507
};

public static ulong Calculate(byte[] data)
{
    ulong crc64 = ulong.MaxValue;
    int length = data.Length;

    for (int i = 0; i < length; i++)
    {
        crc64 = Crc64Table[((uint)(crc64 >> 56) ^ data[i]) & 0xff] ^ (crc64 << 8);
    }

    return ~crc64;
}

---

Looking for a byte[] instead?

Replace return ~crc64; with

crc64 = ~crc64;
return new[]
{
    (byte)((crc64 & 0xff00000000000000) >> 56),
    (byte)((crc64 & 0xff000000000000) >> 48),
    (byte)((crc64 & 0xff0000000000) >> 40),
    (byte)((crc64 & 0xff00000000) >> 32),
    (byte)((crc64 & 0xff000000) >> 24),
    (byte)((crc64 & 0xff0000) >> 16),
    (byte)((crc64 & 0xff00) >> 8),
    (byte)(crc64 & 0xff)
};