Quickstart

Choose a hashing backend

If you're not sure, choose "pycryptodome" because it supports pypy3.

You can find a full list of each currently supported backend in eth_hash.backends.

Install

Put the backend you would like to use in brackets during install, like:

python -m pip install "eth-hash[pycryptodome]"

Compute a Keccak256 Hash

>>> from eth_hash.auto import keccak
>>> keccak(b'')
b"\xc5\xd2F\x01\x86\xf7#<\x92~}\xb2\xdc\xc7\x03\xc0\xe5\x00\xb6S\xca\x82';{\xfa\xd8\x04]\x85\xa4p"

You may also compute hashes incrementally

>>> from eth_hash.auto import keccak
>>> preimage = keccak.new(b'part-a')
>>> preimage.update(b'part-b')
>>> preimage.digest()
b'6\x91l\xdd50\xd6[\x7f\xf9B\xff\xc9SW\x98\xc3\xaal\xd9\xde\xdd6I\xb7\x91\x9e\xf4`pl\x08'

The preimage object returned may be copied as well.

>>> from eth_hash.auto import keccak
>>> preimage = keccak.new(b'part-a')
>>> preimage_copy = preimage.copy()
>>> preimage.update(b'part-b')
>>> preimage.digest()
b'6\x91l\xdd50\xd6[\x7f\xf9B\xff\xc9SW\x98\xc3\xaal\xd9\xde\xdd6I\xb7\x91\x9e\xf4`pl\x08'
>>> preimage_copy.update(b'part-c')
>>> preimage_copy.digest()
b'\xffcy45\xea\xdd\xdf\x8e(\x1c\xfcF\xf3\xd4\xa1S\x0f\xdf\xd8\x01!\xb2(\xe1\xc7\xc6\xa3\x08\xc3\n\x0b'

Select one of many installed backends

If you have several backends installed, you may want to explicitly specify which one to load. You can specify in an environment variable, or at runtime.

Specify backend by environment variable

$ ETH_HASH_BACKEND="pysha3" python
>>> from eth_hash.auto import keccak
# This runs with the pysha3 backend
>>> keccak(b'')
b"\xc5\xd2F\x01\x86\xf7#<\x92~}\xb2\xdc\xc7\x03\xc0\xe5\x00\xb6S\xca\x82';{\xfa\xd8\x04]\x85\xa4p"

Specify backend at runtime

>>> from eth_hash.backends import pysha3
>>> from eth_hash import Keccak256
>>> keccak = Keccak256(pysha3)
>>> keccak(b'')
b"\xc5\xd2F\x01\x86\xf7#<\x92~}\xb2\xdc\xc7\x03\xc0\xe5\x00\xb6S\xca\x82';{\xfa\xd8\x04]\x85\xa4p"

eth_hash.backends package

Submodules

eth_hash.backends.auto module

eth_hash.backends.pycryptodome module

eth_hash.backends.pysha3 module

Module contents

eth_hash package

eth_hash.auto module

eth_hash.main module

Release Notes

eth-hash v0.7.1 (2025-01-13)

Internal Changes - for eth-hash Contributors

eth-hash v0.7.0 (2024-03-01)

Internal Changes - for eth-hash Contributors

eth-hash v0.6.0 (2024-01-10)

Breaking Changes

Internal Changes - for eth-hash Contributors

eth-hash v0.5.2 (2023-06-07)

Internal Changes - for eth-hash Contributors

eth-hash v0.5.1 (2022-11-09)

Features

eth-hash v0.5.0 (2022-07-20)

Performance improvements

eth-hash v0.4.0 (2022-07-06)

Features

Deprecations and Removals

Miscellaneous changes

eth-hash v0.3.3 (2022-06-30)

Performance improvements

Internal Changes - for eth-hash Contributors

eth-hash v0.3.2 (2021-09-03)

Miscellaneous changes

eth-hash v0.3.1 (2021-01-21)

Bugfixes

eth-hash v0.3.0 (2021-01-20)

Features

Internal Changes - for eth-hash Contributors

v0.2.0

Released September 5, 2018

v0.1.4

Released May 28, 2018

v0.1.3

Released May 14, 2018

v0.1.2

Released Apr 2, 2018

v0.1.1

Released Mar 15, 2018

v0.1.0

Released Feb 28, 2018

v0.1.0-alpha.3

Released Feb 7, 2018

v0.1.0-alpha.2

Released Feb 6, 2018

v0.1.0-alpha.1

Contributing

Thank you for your interest in contributing! We welcome all contributions no matter their size. Please read along to learn how to get started. If you get stuck, feel free to ask for help in Ethereum Python Discord server https://discord.gg/GHryRvPB84.

Setting the stage

To get started, fork the repository to your own github account, then clone it to your development machine:

git clone git@github.com:your-github-username/eth-hash.git

Next, install the development dependencies. We recommend using a virtual environment, such as virtualenv https://virtualenv.pypa.io/en/stable/.

cd eth-hash
virtualenv -p python venv
. venv/bin/activate
python -m pip install -e ".[dev]"
pre-commit install

Running the tests

A great way to explore the code base is to run the tests.

We can run all tests with:

pytest tests

Code Style

We use pre-commit https://pre-commit.com/ to enforce a consistent code style across the library. This tool runs automatically with every commit, but you can also run it manually with:

make lint

If you need to make a commit that skips the pre-commit checks, you can do so with git commit --no-verify.

This library uses type hints, which are enforced by the mypy tool (part of the pre-commit checks). All new code is required to land with type hints, with the exception of code within the tests directory.

Documentation

Good documentation will lead to quicker adoption and happier users. Please check out our guide on how to create documentation for the Python Ethereum ecosystem https://github.com/ethereum/snake-charmers-tactical-manual/blob/main/documentation.md.

Pull Requests

It's a good idea to make pull requests early on. A pull request represents the start of a discussion, and doesn't necessarily need to be the final, finished submission.

GitHub's documentation for working on pull requests is available here https://docs.github.com/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/about-pull-requests.

Once you've made a pull request, take a look at the Circle CI build status in the GitHub interface and make sure all tests are passing. In general pull requests that do not pass the CI build yet won't get reviewed unless explicitly requested.

If the pull request introduces changes that should be reflected in the release notes, please add a newsfragment file as explained here https://github.com/ethereum/eth-hash/blob/main/newsfragments/README.md.

If possible, the change to the release notes file should be included in the commit that introduces the feature or bugfix.

Releasing

Releases are typically done from the main branch, except when releasing a beta (in which case the beta is released from main, and the previous stable branch is released from said branch).

Final test before each release

Before releasing a new version, build and test the package that will be released:

git checkout main && git pull
make package-test

This will build the package and install it in a temporary virtual environment. Follow the instructions to activate the venv and test whatever you think is important.

You can also preview the release notes:

towncrier --draft

Build the release notes

Before bumping the version number, build the release notes. You must include the part of the version to bump (see below), which changes how the version number will show in the release notes.

make notes bump=$$VERSION_PART_TO_BUMP$$

If there are any errors, be sure to re-run make notes until it works.

Push the release to github & pypi

After confirming that the release package looks okay, release a new version:

make release bump=$$VERSION_PART_TO_BUMP$$

This command will:

Which version part to bump

$$VERSION_PART_TO_BUMP$$ must be one of: major, minor, patch, stage, or devnum.

The version format for this repo is {major}.{minor}.{patch} for stable, and {major}.{minor}.{patch}-{stage}.{devnum} for unstable (stage can be alpha or beta).

If you are in a beta version, make release bump=stage will switch to a stable.

To issue an unstable version when the current version is stable, specify the new version explicitly, like make release bump="--new-version 4.0.0-alpha.1"

You can see what the result of bumping any particular version part would be with bump-my-version show-bump

Code of Conduct

Our Pledge

In the interest of fostering an open and welcoming environment, we as contributors and maintainers pledge to make participation in our project and our community a harassment-free experience for everyone, regardless of age, body size, disability, ethnicity, gender identity and expression, level of experience, education, socio-economic status, nationality, personal appearance, race, religion, or sexual identity and orientation.

Our Standards

Examples of behavior that contributes to creating a positive environment include:

Examples of unacceptable behavior by participants include:

Our Responsibilities

Project maintainers are responsible for clarifying the standards of acceptable behavior and are expected to take appropriate and fair corrective action in response to any instances of unacceptable behavior.

Project maintainers have the right and responsibility to remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct, or to ban temporarily or permanently any contributor for other behaviors that they deem inappropriate, threatening, offensive, or harmful.

Scope

This Code of Conduct applies both within project spaces and in public spaces when an individual is representing the project or its community. Examples of representing a project or community include using an official project e-mail address, posting via an official social media account, or acting as an appointed representative at an online or offline event. Representation of a project may be further defined and clarified by project maintainers.

Enforcement

Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by contacting the project team at <snakecharmers@ethereum.org>. All complaints will be reviewed and investigated and will result in a response that is deemed necessary and appropriate to the circumstances. The project team is obligated to maintain confidentiality with regard to the reporter of an incident. Further details of specific enforcement policies may be posted separately.

Project maintainers who do not follow or enforce the Code of Conduct in good faith may face temporary or permanent repercussions as determined by other members of the project's leadership.

Attribution

This Code of Conduct is adapted from the Contributor Covenant https://www.contributor-covenant.org, version 1.4, available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html