103 lines
5.8 KiB
Markdown
103 lines
5.8 KiB
Markdown
|
|
|
|
---
|
|
|
|
[](https://github.com/ZcashFoundation/zebra/actions?query=workflow%3ACI+branch%3Amain)
|
|
[](https://codecov.io/gh/ZcashFoundation/zebra)
|
|
|
|
|
|
### 🚧 UNDER CONSTRUCTION 🚧
|
|
|
|
[Zebra](https://zebra.zfnd.org/) is the Zcash Foundation's independent,
|
|
consensus-compatible implementation of the Zcash protocol, currently under
|
|
development. Please [join us on Discord](https://discord.gg/na6QZNd) if you'd
|
|
like to find out more or get involved!
|
|
|
|
Unlike `zcashd`, which originated as a Bitcoin Core fork and inherited its
|
|
monolithic architecture, Zebra has a modular, library-first design, with the
|
|
intent that each component can be independently reused outside of the `zebrad`
|
|
fullnode. For instance, the `zebra-network` crate containing the network stack
|
|
can also be used to implement anonymous transaction relay, network crawlers, or
|
|
other functionality, without requiring a full node.
|
|
|
|
Our first goal is to be able to participate in the network and replicate the
|
|
Zcash chain state, and we intend to ship an alpha before the end of 2020 with
|
|
this functionality. In 2021, we intend to add RPC support and wallet
|
|
integration. This phased approach allows us to test the independent
|
|
implementation of the consensus rules before asking users to entrust it with
|
|
their funds.
|
|
|
|
At a high level, the fullnode functionality required by `zebrad` is factored
|
|
into several components:
|
|
|
|
- [`zebra-chain`](https://doc.zebra.zfnd.org/zebra_chain/index.html), providing
|
|
definitions of core data structures for Zcash, such as blocks, transactions,
|
|
addresses, etc., and related functionality. It also contains the
|
|
implementation of the consensus-critical serialization formats used in Zcash.
|
|
The data structures in `zebra-chain` are defined to enforce [*structural
|
|
validity*](https://zebra.zfnd.org/dev/rfcs/0002-parallel-verification.html#verification-stages) by making invalid states unrepresentable. For instance, the
|
|
`Transaction` enum has variants for each transaction version, and it's
|
|
impossible to construct a transaction with, e.g., spend or output
|
|
descriptions but no binding signature, or, e.g., a version 2 (Sprout)
|
|
transaction with Sapling proofs. Currently, `zebra-chain` is oriented
|
|
towards verifying transactions, but will be extended to support creating them
|
|
in the future.
|
|
|
|
- [`zebra-network`](https://doc.zebra.zfnd.org/zebra_network/index.html),
|
|
providing an asynchronous, multithreaded implementation of the Zcash network
|
|
protocol inherited from Bitcoin. In contrast to `zcashd`, each peer
|
|
connection has a separate state machine, and the crate translates the
|
|
external network protocol into a stateless, request/response-oriented
|
|
protocol for internal use. The crate provides two interfaces: an
|
|
auto-managed connection pool that load-balances requests over available
|
|
peers, and a `connect_isolated` method that produces a peer connection
|
|
completely isolated from all other node state. This can be used, for
|
|
instance, to safely relay data over Tor, without revealing distinguishing
|
|
information.
|
|
|
|
- [`zebra-script`](https://doc.zebra.zfnd.org/zebra_script/index.html) provides
|
|
script validation. Currently, this is implemented by linking to the C++
|
|
script verification code from `zcashd`, but in the future we may implement a
|
|
pure-Rust script implementation.
|
|
|
|
- [`zebra-consensus`](https://doc.zebra.zfnd.org/zebra_consensus/index.html)
|
|
performs [*semantic validation*](https://zebra.zfnd.org/dev/rfcs/0002-parallel-verification.html#verification-stages) of blocks and transactions: all consensus
|
|
rules that can be checked independently of the chain state, such as
|
|
verification of signatures, proofs, and scripts. Internally, the library
|
|
uses [`tower-batch`](https://doc.zebra.zfnd.org/tower_batch/index.html) to
|
|
perform automatic, transparent batch processing of contemporaneous
|
|
verification requests.
|
|
|
|
- [`zebra-state`](https://doc.zebra.zfnd.org/zebra_state/index.html) is
|
|
responsible for storing, updating, and querying the chain state. The state
|
|
service is responsible for [*contextual verification*](https://zebra.zfnd.org/dev/rfcs/0002-parallel-verification.html#verification-stages): all consensus rules
|
|
that check whether a new block is a valid extension of an existing chain,
|
|
such as updating the nullifier set or checking that transaction inputs remain
|
|
unspent.
|
|
|
|
- [`zebrad`](https://doc.zebra.zfnd.org/zebrad/index.html) contains the full
|
|
node, which connects these components together and implements logic to handle
|
|
inbound requests from peers and the chain sync process.
|
|
|
|
- `zebra-rpc` and `zebra-client` will eventually contain the RPC and wallet
|
|
functionality, but as mentioned above, our goal is to implement replication
|
|
of chain state first before asking users to entrust Zebra with their funds.
|
|
|
|
All of these components can be reused as independent libraries, and all
|
|
communication between stateful components is handled internally by
|
|
[internal asynchronous RPC abstraction](https://docs.rs/tower/) ("microservices in one process").
|
|
|
|
The [Zebra website](https://zebra.zfnd.org/) contains user documentation, such
|
|
as how to run or configure Zebra, set up metrics integrations, etc., as well as
|
|
developer documentation, such as design documents. We also render [API
|
|
documentation](https://doc.zebra.zfnd.org) for the external API of our crates,
|
|
as well as [internal documentation](https://doc-internal.zebra.zfnd.org) for
|
|
private APIs.
|
|
|
|
## License
|
|
|
|
Zebra is distributed under the terms of both the MIT license
|
|
and the Apache License (Version 2.0).
|
|
|
|
See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT).
|