Cryptology ePrint Archive: Report 2015/678

Optimizing MAKWA on GPU and CPU

Thomas Pornin

Abstract: 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.

Category / Keywords: secret-key cryptography / Password Hashing Competition

Date: received 5 Jul 2015

Contact author: pornin at bolet org

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Version: 20150706:211111 (All versions of this report)

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