International Association
for Cryptologic Research

We present here optimized implementations of the MAKWA password hashing

function on an AMD Radeon HD 7990 GPU, and compare its efficiency with an Intel

i7 4770K CPU for systematic dictionary attacks. We find that the GPU seems to

get more hashing done for a given budget, but not by a large amount (the GPU is less

than twice as efficient as the CPU). Raising the MAKWA modulus size to 4096 bits,

instead of the default 2048 bits, should restore the balance in favour of the CPU. We

also find that power consumption, not hardware retail price, is likely to become the

dominant factor for industrialized, long-term attacking efforts.