IN PROGRESS -- don't expect everything to work yet.

This Python2/3 library provides an easy interface to the Zcash data structures and protocol. The approach is low-level and "ground up", with a focus on providing tools to manipulate the internals of how Zcash works.

This library was originally forked from python-bitcoinlib.

sudo apt-get install libssl-dev

The RPC interface, zcash.rpc, is designed to work with Zcash v1.0.0 Older versions may not work.

Everything consensus critical is found in the modules under zcash.core. This rule is followed pretty strictly, for instance chain parameters are split into consensus critical and non-consensus-critical.

zcash.core            - Basic core definitions, datastructures, and
                          (context-independent) validation
zcash.core.key        - ECC pubkeys
zcash.core.script     - Scripts and opcodes
zcash.core.scripteval - Script evaluation/verification
zcash.core.serialize  - Serialization

In the future the zcash.core may use the Satoshi sourcecode directly as a library. Non-consensus critical modules include the following:

zcash          - Chain selection
zcash.base58   - Base58 encoding
zcash.bloom    - Bloom filters (incomplete)
zcash.net      - Network communication (in flux)
zcash.messages - Network messages (in flux)
zcash.rpc      - Zcash RPC interface support
zcash.wallet   - Wallet-related code, currently Zcash t-address and
                   private key support

Functions related to Zcash's zero-knowledge proofs resides under zcash.core.zkproofs.

Effort has been made to follow the Satoshi source relatively closely, for instance Python code and classes that duplicate the functionality of corresponding Satoshi C++ code uses the same naming conventions: CTransaction, CBlockHeader, nValue etc. Otherwise Python naming conventions are followed.

Like the Zcash codebase CTransaction is immutable and CMutableTransaction is mutable; unlike the Zcash codebase this distinction also applies to COutPoint, CTxIn, CTxOut, and CBlock.

Rather confusingly, Bitcoin and thus Zcash shows transaction and block hashes as little-endian hex rather than the big-endian, which the rest of the world uses for SHA256. python-zcashlib provides the convenience functions x() and lx() in zcash.core to convert from big-endian and little-endian hex to raw bytes to accomodate this. In addition see b2x() and b2lx() for conversion from bytes to big/little-endian hex.

While not always good style, it's often convenient for quick scripts if import * can be used. To support that all the modules have __all__ defined appropriately.

See examples/ directory. For instance this example creates a transaction spending a pay-to-script-hash transaction output:

$ PYTHONPATH=. examples/spend-pay-to-script-hash-txout.py
<hex-encoded transaction>

Do the following:

import zcash
zcash.SelectParams(NAME)

Where NAME is one of 'testnet', 'mainnet', or 'regtest'. The chain currently selected is a global variable that changes behavior everywhere, just like in the Satoshi codebase.

Under zcash/tests using test data from Zcash. To run them:

python -m unittest discover && python3 -m unittest discover

Please run the tests on both Python2 and Python3 for your pull-reqs!

Alternately, if Tox (see https://tox.readthedocs.org/) is available on your system, you can run unit tests for multiple Python versions:

./runtests.sh

Currently, the following implementations are tried (any not installed are skipped):

* CPython 2.7
* CPython 3.3
* CPython 3.4
* CPython 3.5
* PyPy
* PyPy3

HTML coverage reports can then be found in the htmlcov/ subdirectory.

TODO Documentation is not updated for Zcash.

Sphinx documentation is in the "doc" subdirectory. Run "make help" from there to see how to build. You will need the Python "sphinx" package installed.

Currently this is just API documentation generated from the code and docstrings. Higher level written docs would be useful, perhaps starting with much of this README. Pages are written in reStructuredText and linked from index.rst.