py_ecc

Elliptic curve crypto in python including secp256k1, alt_bn128, and bls12_381.

Warning: This library contains some experimental codes that have NOT been audited.

Read more in the documentation below. View the change log

Quickstart

python -m pip install py_ecc

BLS Signatures

py_ecc implements the IETF BLS draft standard v4 as per the inter-blockchain standardization agreement. The BLS standards specify different ciphersuites which each have different functionality to accommodate various use cases. The following ciphersuites are available from this library:

• G2Basic also known as BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_NUL_
• G2MessageAugmentation also known as BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_AUG_
• G2ProofOfPossession also known as BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_POP_

Basic Usage

from py_ecc.bls import G2ProofOfPossession as bls_pop

private_key = 5566
public_key = bls_pop.SkToPk(private_key)

message = b'\xab' * 32  # The message to be signed

# Signing
signature = bls_pop.Sign(private_key, message)

# Verifying
assert bls_pop.Verify(public_key, message, signature)

Aggregating Signatures

private_keys = [3, 14, 159]
public_keys = [bls_pop.SkToPk(key) for key in private_keys]
signatures = [bls_pop.Sign(key, message) for key in private_keys]

# Aggregating
agg_sig = bls_pop.Aggregate(signatures)

# Verifying signatures over the same message.
# Note this is only safe if Proofs of Possession have been verified for each of the public keys beforehand.
# See the BLS standards for why this is the case.
assert bls_pop.FastAggregateVerify(public_keys, message, agg_sig)

Multiple Aggregation

messages = [b'\xaa' * 42, b'\xbb' * 32, b'\xcc' * 64]
signatures = [bls_pop.Sign(key, message) for key, message in zip(private_keys, messages)]
agg_sig = bls_pop.Aggregate(signatures)

# Verify aggregate signature with different messages
assert bls_pop.AggregateVerify(public_keys, messages, agg_sig)

Developer Setup

If you would like to hack on py_ecc, please check out the Snake Charmers Tactical Manual for information on how we do:

• Testing
• Pull Requests
• Documentation

We use pre-commit to maintain consistent code style. Once installed, it will run automatically with every commit. 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.

Development Environment Setup

You can set up your dev environment with:

git clone git@github.com:ethereum/py_ecc.git
cd py_ecc
virtualenv -p python3 venv
. venv/bin/activate
python -m pip install -e ".[dev]"
pre-commit install

Release setup

To release a new version:

make release bump=$$VERSION_PART_TO_BUMP$$

How to bumpversion

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).

To issue the next version in line, specify which part to bump, like make release bump=minor or make release bump=devnum. This is 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).

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 devnum"