[gpderetta]

CLMUL is quite interesting. I learned about it when going in depth on how multiplications help with hashing.

A multiplication is in practice: - a sum over - a series (i.e. one for each bit set in the multiplier) - of shifts (where the shift amount is the index of that bit in the multiplier)

The shifting and the combining are great for hashing as they "distribute" each bit around.

CLMUL simply replaces the addition in step one with xor (which can also be thought as the single bit carryless addition).