Keccak256 based Binary Merklization

[itzmeanjan]

I'm following https://keccak.team/files/Keccak-implementation-3.2.pdf for implementing keccak256 2-to-1 hash function, which is used for computing all intermediate nodes of binary merkle tree.

Note, keccak256 is almost similar to sha3-256, except padding rule difference

merklize-sha/include/sha3_256.hpp

Line 43 in f03707f

state[8] = 0b110ull;

vs

merklize-sha/include/keccak_256.hpp

Line 51 in f03707f

state[8] = 0b1ull;

[itzmeanjan]

As SHA3-256 and KECCAK-256 implementations are almost same, benchmark results are very close !

See https://github.com/itzmeanjan/merklize-sha/tree/3a5fa2998a0f51761c651eee1ac908e96dc26a2e/results/keccak-256 for keccak256 benchmark on multiple CPUs/ GPUs

[itzmeanjan]

⭐

merklize-sha/results/keccak-256/nvidia_gpu.md

Lines 12 to 23 in 3a5fa29

	running on Tesla V100-SXM2-16GB
	Benchmarking Binary Merklization using KECCAK-256
	leaf count execution time host-to-device tx time device-to-host tx time
	2 ^ 20 751.924875 us 1.167792 ms 1.005363 ms
	2 ^ 21 1.344910 ms 2.304931 ms 2.016678 ms
	2 ^ 22 2.517974 ms 4.593017 ms 4.025208 ms
	2 ^ 23 4.864380 ms 9.128906 ms 8.053345 ms
	2 ^ 24 8.179686 ms 18.250488 ms 16.049194 ms
	2 ^ 25 16.144776 ms 36.534668 ms 32.099121 ms