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9.8 KiB
9.8 KiB
Coincurve
=========
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-----
This library provides well-tested Python CFFI bindings for
`libsecp256k1 <https://github.com/bitcoin-core/secp256k1>`_, the heavily
optimized C library used by `Bitcoin Core <https://github.com/bitcoin/bitcoin>`_
for operations on elliptic curve secp256k1.
Table of Contents
~~~~~~~~~~~~~~~~~
.. contents::
:backlinks: top
:local:
Features
--------
- Fastest available implementation (more than 10x faster than OpenSSL)
- Clean, easy to use API
- Frequent updates from `libsecp256k1 <https://github.com/bitcoin-core/secp256k1>`_ master
- Linux, macOS, and Windows all have binary packages for both 64 and 32-bit architectures
- Linux & macOS use GMP for faster computation
- Deterministic signatures via `RFC 6979 <https://tools.ietf.org/html/rfc6979>`_
- Non-malleable signatures (lower-S form) by default
- Secure, non-malleable `ECDH implementation <https://github.com/ofek/coincurve/issues/9#issuecomment-329235214>`_
- Implements a fix for `<https://bugs.python.org/issue28150>`_ to support Python 3.6+ on macOS
Users
-----
- `<https://www.ethereum.org>`_
- `<https://lbry.io>`_
- `<https://libp2p.io>`_
- `<https://zeronet.io>`_
- `<https://ark.io>`_
- `<https://www.augur.net>`_
- `<https://www.nucypher.com>`_
- `<https://raiden.network>`_
- `<https://golem.network>`_
- `<https://omisego.network>`_
and `many more <https://github.com/ofek/coincurve/blob/master/DOWNSTREAM.rst>`_
Installation
------------
Coincurve is distributed on PyPI and is available on Linux/macOS and Windows and
supports Python 2.7/3.5+ and PyPy3.5-v5.8.1+.
.. code-block:: bash
$ pip install coincurve
If you are on a system that doesn't have a precompiled binary wheel (e.g. FreeBSD)
then pip will fetch source to build yourself. You must have the necessary packages.
On Debian/Ubuntu the necessary system packages are:
- ``build-essential``
- ``automake``
- ``pkg-config``
- ``libtool``
- ``libffi-dev``
- ``python3-dev`` (or ``python-dev`` for Python 2)
- ``libgmp-dev`` (optional)
On macOS the necessary Homebrew packages are:
- ``automake``
- ``pkg-config``
- ``libtool``
- ``libffi``
- ``gmp`` (optional)
API
---
Coincurve provides a simple API.
coincurve.verify_signature
^^^^^^^^^^^^^^^^^^^^^^^^^^
``verify_signature(signature, message, public_key, hasher=sha256, context=GLOBAL_CONTEXT)``
Verifies some message was signed by the owner of a public key.
* Parameters:
- **signature** (``bytes``) - The signature to verify.
- **message** (``bytes``) - The message that was supposedly signed.
- **public_key** (``bytes``) - A public key in compressed or uncompressed form.
- **hasher** - The hash function to use, can be ``None``. hasher(message) must return 32 bytes.
- **context** (``coincurve.Context``)
* Returns: ``bool``
coincurve.PrivateKey
^^^^^^^^^^^^^^^^^^^^
All instances have a ``public_key`` of type ``coincurve.PublicKey``
``PrivateKey(secret=None, context=GLOBAL_CONTEXT)``
* Parameters:
- **secret** (``bytes``) - The secret to use.
- **context** (``coincurve.Context``)
**Methods:**
*classmethod* ``from_hex(hexed, context=GLOBAL_CONTEXT)``
*classmethod* ``from_int(num, context=GLOBAL_CONTEXT)``
*classmethod* ``from_pem(pem, context=GLOBAL_CONTEXT)``
*classmethod* ``from_der(der, context=GLOBAL_CONTEXT)``
``sign(message, hasher=sha256, custom_nonce=None)``
* Parameters:
- **message** (``bytes``) - The message to sign.
- **hasher** - The hash function to use, can be ``None``. hasher(message) must return 32 bytes.
- **custom_nonce** - A tuple of arity 2 in the form of ``(nonce_fn, nonce_data)``. Refer to:
`secp256k1.h <https://github.com/bitcoin-core/secp256k1/blob/b8c26a39903de7bf1d789232e030319116b011ac/include/secp256k1.h#L449-L450>`_
* Returns: ``bytes``. 68 <= len(signature) <= 71
``sign_recoverable(message, hasher=sha256)``
* Parameters:
- **message** (``bytes``) - The message to sign.
- **hasher** - The hash function to use, can be ``None``. hasher(message) must return 32 bytes.
* Returns: ``bytes``
``ecdh(public_key)``
Computes a Diffie-Hellman secret in constant time. **Note:** This prevents malleability by returning
``sha256(compressed_public_key)`` instead of the ``x`` coordinate directly. See `<https://github.com/ofek/coincurve/issues/9>`_.
* Parameters:
- **public_key** (``bytes``) - Another party's public key in compressed or uncompressed form.
* Returns: ``bytes``
``add(scalar, update=False)``
* Parameters:
- **scalar** (``bytes``) - The scalar to add.
- **update** (``bool``) - If ``True``, will update and return ``self``.
* Returns: ``coincurve.PrivateKey``
``multiply(scalar, update=False)``
* Parameters:
- **scalar** (``bytes``) - The scalar to multiply.
- **update** (``bool``) - If ``True``, will update and return ``self``.
* Returns: ``coincurve.PrivateKey``
``to_hex()``
``to_int()``
``to_pem()``
``to_der()``
coincurve.PublicKey
^^^^^^^^^^^^^^^^^^^
``PublicKey(data, context=GLOBAL_CONTEXT)``
* Parameters:
- **data** (``bytes``) - The public key in compressed or uncompressed form.
- **context** (``coincurve.Context``)
**Methods:**
*classmethod* ``from_secret(secret, context=GLOBAL_CONTEXT)``
*classmethod* ``from_valid_secret(secret, context=GLOBAL_CONTEXT)``
*classmethod* ``from_point(x, y, context=GLOBAL_CONTEXT)``
*classmethod* ``from_signature_and_message(serialized_sig, message, hasher=sha256, context=GLOBAL_CONTEXT)``
*classmethod* ``combine_keys(public_keys, context=GLOBAL_CONTEXT)``
* Parameters:
- **public_keys** (``list``) - A ``list`` of ``coincurve.PublicKey`` to add.
- **context** (``coincurve.Context``)
* Returns: ``coincurve.PublicKey``
``format(compressed=True)``
* Parameters:
- **compressed** (``bool``)
* Returns: The public key serialized to ``bytes``.
``point()``
* Returns: (x, y)
``verify(signature, message, hasher=sha256)``
Verifies some message was signed by the owner of this public key.
* Parameters:
- **signature** (``bytes``) - The signature to verify.
- **message** (``bytes``) - The message that was supposedly signed.
- **hasher** - The hash function to use, can be ``None``. hasher(message) must return 32 bytes.
* Returns: ``bool``
``add(scalar, update=False)``
* Parameters:
- **scalar** (``bytes``) - The scalar to add.
- **update** (``bool``) - If ``True``, will update and return ``self``.
* Returns: ``coincurve.PublicKey``
``multiply(scalar, update=False)``
* Parameters:
- **scalar** (``bytes``) - The scalar to multiply.
- **update** (``bool``) - If ``True``, will update and return ``self``.
* Returns: ``coincurve.PublicKey``
``combine(public_keys, update=False)``
* Parameters:
- **public_keys** (``list``) - A ``list`` of ``coincurve.PublicKey`` to add.
- **update** (``bool``) - If ``True``, will update and return ``self``.
* Returns: ``coincurve.PublicKey``
License
-------
Coincurve is distributed under the terms of both
- `Apache License, Version 2.0 <https://choosealicense.com/licenses/apache-2.0>`_
- `MIT License <https://choosealicense.com/licenses/mit>`_
at your option.
Credits
-------
- Contributors of `libsecp256k1 <https://github.com/bitcoin-core/secp256k1>`_.
- Contributors of `secp256k1-py <https://github.com/ludbb/secp256k1-py>`_.
While Coincurve is nearly a complete rewrite, much of the build system
provided by `ulope <https://github.com/ulope>`_ remains.
History
-------
Important changes are emphasized.
14.0.0
^^^^^^
**IMPORTANT: This will be the final release that supports Python 2.**
- **New:** Binary wheels for Python 3.9!
- **Breaking:** Drop support for Python 3.5
- Fetch libsecp256k1 source if the system installation lacks ECDH support
- Fix innocuous ``setuptools`` warning when building from source
- Switch CI/CD to GitHub Actions
13.0.0
^^^^^^
- **New:** Binary wheels for Python 3.8!
- Support building on OpenBSD
- Improve handling of PEM private key deserialization
- Improve ECDH documentation
- Improvements from libsecp256k1 master
12.0.0
^^^^^^
- **New:** Binary wheels on Linux for PyPy3.6 v7.1.1-beta!
- **New:** Binary wheels on macOS for Python 3.8.0-alpha.3!
- **New:** Binary wheels on Linux are now also built with the new `manylinux2010 <https://www.python.org/dev/peps/pep-0571>`_ spec for 64-bit platforms!
- Improvements from libsecp256k1 master
11.0.0
^^^^^^
- Fix some linking scenarios by placing bundled libsecp256k1 dir first in path
- Allow override of system libsecp256k1 with environment variable
- Add benchmarks
- Use Codecov to track coverage
- Use black for code formatting
10.0.0
^^^^^^
- Support tox for testing
- Compatibility with latest libsecp256k1 ECDH API
- Make libgmp optional when building from source
9.0.0
^^^^^
- Fixed wheels for macOS
- **Breaking:** Drop support for 32-bit macOS
View `all history <https://github.com/ofek/coincurve/blob/master/HISTORY.rst>`_