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6.4 KiB
6.4 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.
Coincurve replaces `secp256k1-py <https://github.com/ludbb/secp256k1-py>`_.
New features include:
- Cleaner API
- Uses newest version of `libsecp256k1 <https://github.com/bitcoin-core/secp256k1>`_
- Support for Windows
- Linux, macOS, and Windows all have binary packages for both 64 and 32-bit architectures
- Linux & macOS use GMP for faster computation
- Endomorphism optimization is enabled
- A global context is used by default, drastically increasing performance
- Fixed ECDH
- A fix to remove CFFI warnings
- Implements a fix for `<https://bugs.python.org/issue28150>`_ to support Python 3.6+ on macOS
Table of Contents
~~~~~~~~~~~~~~~~~
.. contents::
:backlinks: top
:local:
Installation
------------
Coincurve is distributed on PyPI and is available on Linux/macOS and Windows and
supports Python 2.7/3.5+ and PyPy3.5-v5.7.1+.
.. 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 for example the necessary packages are:
- build-essential
- automake
- pkg-config
- libtool
- libffi-dev
- libgmp-dev
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)``
* Parameters:
- **message** (``bytes``) - The message to sign.
- **hasher** - The hash function to use, can be ``None``. hasher(message) must return 32 bytes.
* Returns: ``bytes``. 71 <= len(signature) <= 72
``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.
* 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** - If ``True``, will update and return ``self``.
* Returns: ``coincurve.PrivateKey``
``multiply(scalar, update=False)``
* Parameters:
- **scalar** (``bytes``) - The scalar to multiply.
- **update** - 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)``
``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** - If ``True``, will update and return ``self``.
* Returns: ``coincurve.PublicKey``
``multiply(scalar, update=False)``
* Parameters:
- **scalar** (``bytes``) - The scalar to multiply.
- **update** - 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.
Changelog
---------
Important changes are emphasized.
5.0.0
^^^^^
- **Breaking:** Coincurve is now dual-licensed under the terms of MIT and Apache v2.0.
- Improvements to documentation.
4.5.1
^^^^^
- First public stable release