Cross-platform Python CFFI bindings for libsecp256k1
Project description
This library provides well-tested Python CFFI bindings for libsecp256k1, the heavily optimized C library used by Bitcoin Core for operations on elliptic curve secp256k1.
Coincurve replaces secp256k1-py.
New features include:
Cleaner API
Uses newest version of libsecp256k1
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
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
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+.
$ pip install coincurveIf 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, 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
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.
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
at your option.
Credits
Contributors of libsecp256k1.
Contributors of secp256k1-py. While Coincurve is nearly a complete rewrite, much of the build system provided by ulope remains.
Changelog
Important changes are emphasized.
7.0.0
Improvements from libsecp256k1 master
Fix build script
6.0.0
Resolved #6. You can choose to use this or remain on 5.2.0. This will only be a temporary change. See https://github.com/ofek/coincurve/commit/3e93480b3e38c6b9beb0bc2de83bc3630fc74c46
5.2.0
Added support for supplying a custom nonce to PrivateKey.sign.
5.1.0
Added PublicKey.combine_keys class method.
Improvements to documentation.
5.0.1
Fixed an issue where validate_secret would occasionally erroneously error on user-provided secrets (secrets not generated by Coincurve itself) if there were not exactly 256 bits of entropy. See #5
5.0.0
4.5.1
First public stable release
