> For a start why don't you print out the hashes of 1-255 and then > find out how easy it is to deduce the last bit of the hash result.
They're available in lib/crc32table.h, as crc32ctable_le[0]. As a CRC is a linear function, every bit is the XOR of some selected bits of the input, i.e. the parity of the input and some bit-specific mask sequence. Furthermore, CRCs are cyclic, so the mask sequences for adjacent bits are shifts of each other. The lsbit of the CRC32c of x is the parity of x & 0x1f. This is because the LFSR sequence generated by the polynomial starts 0001111110010001110010101111011000111000011011110010110000100101... The first bit corresponds to the msbit of the last byte. How does this implicate the low bits specifically? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
