A Python library for 'bitcoin cryptography'
btclib is a Python3 type annotated library intended for teaching, learning, and using bitcoin, its blockchain, and the associated elliptic curve cryptography.
It is rigorously and extensively tested: the test suite covers 100% of the code base and reproduces results from both informal and major reference sources.
Originally developed for the Bitcoin and Blockchain Technology course at the University of Milano-Bicocca, btclib is not intended for production environments: it is often refactored for improved clarity, without care for backward compatibility; moreover, some of its algorithms could be broken using side-channel attacks.
Included features are:
- modulo algebra functions (gcd, inverse, legendre symbol, square root)
- octets / integer / point / var_int / var_bytes helper functions
- elliptic curve class
- fast algebra implemented using Jacobian coordinates
- double scalar multiplication (Straus's algorithm, also known as Shamir's trick)
- multi scalar multiplication (Bos-coster's algorithm)
- point simmetry solution: odd/even, low/high, and quadratic residue
- elliptic curves: SEC 1 v1 and v2, NIST, Brainpool, and low cardinality test curves
- ECDSA signature with (transaction) DER encoding
- ECDSA signature with (message) compact encoding: standard p2pkh and BIP137/Electrum extensions to p2wpkh and p2wpkh-p2sh
- EC Schnorr signature (according to
BIP340
bitcoin standardization)
- batch validation
- threshold signature (see test-suite)
- MuSig multi-signature (see test-suite)
- Borromean ring signature
- RFC 6979 to make signature schemes deterministic
- Sign-to-contract commitment
- Diffie-Hellman
- Pedersen committment
- Base58 encoding/decoding
- p2pkh/p2sh addresses and WIFs
- Bech32 encoding/decoding
- p2wpkh/p2wsh native SegWit addresses and their legacy p2sh-wrapped versions
- BIP32 hierarchical deterministic key chains
- SLIP132 key versions (xprv, yprv, zprv, Yprv, Zprv, tprv, uprv, vprv, and Uprv) with corresponding mapping to p2pkh/p2sh, p2wpkh-p2sh, p2wpkh, p2wsh-p2sh, p2wsh and p2tr addresses
- BIP39 wordlists and mnemonic for generating deterministic keys
- Electrum standard for mnemonic
- Script encoding/decoding
- nulldata, p2pk, p2ms, p2pkh, p2sh, p2wpkh, p2wsh and p2tr ScriptPubKeys
- BlockHeader and Block data classes
- OutPoint, TxIn, TxOut, and TX data classes
- legacy, segwit_v0 and taproot transaction hash signatures
- BIP174 partially signed bitcoin transactions (PSBT): PsbtIn, PbstOut, and Psbt data classes
To install (and/or upgrade) btclib:
python -m pip install --upgrade btclib
You might want to install btclib into a python virtual environment; e.g. from the root folder:
Bash shell
python -m venv venv_btclib
source ./venv_btclib/bin/activate
python -m pip install --upgrade btclib
Windows CMD or PowerShell:
python -m venv venv_btclib
.\venv_btclib\Scripts\activate
python -m pip install --upgrade btclib
Windows Git bash shell:
python -m venv venv_btclib
cd ./venv_btclib/Scripts
. activate
cd ../..
python -m pip install --upgrade btclib
Some development tools are required to develop and test btclib; they can be installed with:
python -m pip install --upgrade -r requirements-dev.txt
Some additional packages are needed to build the documentation:
python -m pip install --upgrade -r docs/requirements.txt
Developers might also consider to install btclib in editable way:
python -m pip install --upgrade -e ./