# Descriptor wallet library

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Library for building descriptor-based bitcoin wallets. Everything a modern
cold and hot bitcoin wallet needs, but which is not (yet) a part of
[rust-bitcoin](https://crates.io/bitcoin) library.

The library clearly separates parts requiring access to private keys from
those which should operate never touching them. It is advised that wallets
should be designed in a way assuming zero private key access for all of their
operations aside from transaction signing; this part must be separated into
other repository/library and be strictly controlled. One may look after
command-line `btc-hot` and `btc-cold` wallets in [`bin`](bin) directory for an
example of how this can be done.

Library provides

- efficient manipulations with BIP-32 derivation paths, separating derivations
  requiring private key access from those, which will always operate without;
- miniscript & classical bitcoin descriptors;
- PSBT constructor using input descriptors, which allow to specify custom
  information about RBFs, previous public key P2C tweaks and custom hash types
  on a per-input basis;
- PSBT signer, supporting RBFs, relative and absolute timelocks, all sighash
  types, complex scripts, including witness- and taproot-based;
- script templates allowing embedding extended pubkeys into bitcoin script
  assembly;
- lexicographic ordering of transaction & PSBT inputs & oututs;
- script type system;
- helper types for working with hash-lock contracts;
- PSBT utility functions (retrieving previous output, computing fee);
- transaction resolver API on top of Electrum Server API for convenience
  computation of already-mined transaction fees etc;
- support for SLIP-32/132 extended pubkey types (`ypub`, `zprv` etc).

![Wallet comparison diagram](./doc/assets/comparison.png)

## Command-line wallets

One may install command-line wallets with the following command (requires
rust compiler and `rustup` tools to be already installed on a system):

```console
$ rustup default stable
$ rustup update
$ git clone https://github.com/BP-WG/descriptor-wallet
$ cd descriptor-wallet
$ cargo install --path . --locked --all-features
```

This will add `btc-hot` and `btc-cold` commands to the system.

[bin]: https://github.com/BP-WG/descriptor-wallet/tree/master/src/bin

### Install with Docker

#### Build

Clone the repository and checkout to the desired version (here `v0.8.0`):

```console
$ git clone https://github.com/BP-WG/descriptor-wallet
$ cd descriptor-wallet
$ git checkout v0.8.0
```

Build and tag the Docker image:

```console
$ docker build -t descriptor-wallet:v0.8.0 .
```

#### Usage

```console
$ docker run descriptor-wallet:v0.8.0 btc-hot --help
$ docker run descriptor-wallet:v0.8.0 btc-cold --help
```

#### Examples with files

```console
$ docker run -v $PWD/data:/data descriptor-wallet:v0.8.0 btc-hot seed /data/testnet.seed
$ docker run -v $PWD/data:/data descriptor-wallet:v0.8.0 btc-hot derive --testnet /data/testnet.seed /data/testnet
```