C/C++ implementation of Ethash – the Ethereum Proof of Work algorithm
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chfast ethash 0.4.3
Bump version: 0.4.2 → 0.4.3
Latest commit 441af90 Feb 19, 2019



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C/C++ implementation of Ethash – the Ethereum Proof of Work algorithm

Table of Contents


Build from source using CMake.

mkdir build
cd build
cmake ..
cmake --build .


See ethash.hpp for list of exported function and documentation.

Test vectors


This section decscribes the optimizations, modification and tweaks applied in this library in relation to Ethash reference implementation.

The library contains a set of micro-benchmarks. Build and run bench tool.

Seed hash is computed on the fly.

Seed hash is sequence of keccak256 hashes applied the epoch number of times. Time needed to compute seed hash is negligible comparing to time needed to build light cache. Computing seed hash for epoch 10000 takes ~ 5 ms, building light cache for epoch 1 takes ~ 500 ms.

Dataset size is computed on the fly

Computing the size of full dataset and light cache requires finding the largest prime number given an upper bound. For similar reasons as with seed hash, this is computed on the fly. The procedure used is quite naive and forks well only up to 40-bit number, so some additional improvement can be done in future.


Paweł Bylica @chfast


Licensed under the Apache License, Version 2.0.