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Chia Proof of Space

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Chia's proof of space is written in C++. Includes a plotter, prover, and verifier. It exclusively runs on 64 bit architectures. Read the Proof of Space document to learn about what proof of space is and how it works.

C++ Usage Instructions


# Requires cmake 3.14+

mkdir -p build && cd build
cmake ../
cmake --build . -- -j 6

Static Compilation With glibc

Statically compile ProofOfSpace

mkdir -p build && cd build
cmake --build . -- -j 6

Run tests


CLI usage

./ProofOfSpace -k 25 -f "plot.dat" -m "0x1234" create
./ProofOfSpace -k 25 -f "final-plot.dat" -m "0x4567" -t TMPDIR -2 SECOND_TMPDIR create
./ProofOfSpace -f "plot.dat" prove <32 byte hex challenge>
./ProofOfSpace -k 25 verify <hex proof> <32 byte hex challenge>
./ProofOfSpace -f "plot.dat" check <iterations>


time ./ProofOfSpace -k 25 create

Hellman Attacks usage

There is an experimental implementation which implements some of the Hellman Attacks that can provide significant space savings for the final file.

./HellmanAttacks -k 18 -f "plot.dat" -m "0x1234" create
./HellmanAttacks -f "plot.dat" check <iterations>


Finally, python bindings are provided in the python-bindings directory.


python3 -m venv .venv
. .venv/bin/activate
pip3 install .

Run python tests

Testings uses pytest. Linting uses flake8 and mypy.

py.test ./tests -s -v

ci Building

The primary build process for this repository is to use GitHub Actions to build binary wheels for MacOS, Linux (x64 and aarch64), and Windows and publish them with a source wheel on PyPi. See .github/workflows/build.yml. CMake uses FetchContent to download pybind11. Building is then managed by cibuildwheel. Further installation is then available via pip install chiapos e.g.

Contributing and workflow

Contributions are welcome and more details are available in chia-blockchain's

The main branch is usually the currently released latest version on PyPI. Note that at times chiapos will be ahead of the release version that chia-blockchain requires in it's main/release version in preparation for a new chia-blockchain release. Please branch or fork main and then create a pull request to the main branch. Linear merging is enforced on main and merging requires a completed review. PRs will kick off a GitHub actions ci build and analysis of chiapos at Please make sure your build is passing and that it does not increase alerts at lgtm.