# BIP-0173 [](https://travis-ci.org/lukaszsamson/elixir-bip0173)
**Elixir implementation of Bitcoin's address format for native SegWit and Taproot outputs.**
Upstream GitHub repository: [lukaszsamson/elixir-bip0173](https://github.com/lukaszsamson/elixir-bip0173)
## Differences from [stampery/elixir-bip0173](https://github.com/stampery/elixir-bip0173)
This fork adds support for BIP-0350 Bech32m Taproot address format and fixes validation issues in SegWit addresses basing on testcases from BIP-0173. It also introduces support for Litecoin MimbleWimble addresses (witness 0, length 66)
## About BIP-0173, BIP-0350 and Bech32 and Bech32m
[BIP-0173](https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki) proposes a checksummed base32 format, "Bech32", and a standard for native segregated witness output addresses using it.
[BIP-0141](https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki) defines Segregated Witness v0 and witness programs.
[BIP-0350](https://github.com/bitcoin/bips/blob/master/bip-0350.mediawiki) Bech32m format for v1+ witness addresses.
You can find more information in [the original proposal](https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki) by [@sipa](https://github.com/sipa) and [@gmaxwell](https://github.com/gmaxwell).
## Installation
1. Add `bip0173` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[{:bip0173, "~> 0.2.0", hex: :bip0173_0350}]
end
```
## How to use
You can find the full API reference and examples in the [online documentation at Hexdocs](https://hexdocs.pm/bip0173/api-reference.html).
### Bech32
#### Encoding data to Bech32 and Bech32m string
```elixir
iex> Bech32.encode("bech32", [0, 1, 2], :bech32)
"bech321qpz4nc4pe"
```
```elixir
iex> Bech32.encode("bech32", [0, 1, 2], :bech32m)
"bech321qpzq0geym"
```
```elixir
iex> Bech32.encode("bc", [0, 14, 20, 15, 7, 13, 26, 0, 25, 18, 6, 11, 13,
...> 8, 21, 4, 20, 3, 17, 2, 29, 3, 12, 29, 3, 4, 15, 24,20, 6, 14, 30, 22], :bech32)
"bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4"
```
#### Decoding data from Bech32 and Bech32m string
```elixir
iex> Bech32.decode("bech321qpz4nc4pe")
{:ok, {"bech32", [0, 1, 2], :bech32}}
```
```elixir
iex> Bech32.decode("bech321qpzq0geym")
{:ok, {"bech32", [0, 1, 2], :bech32m}}
```
``` elixir
iex> Bech32.decode("bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4")
{:ok, {"bc", [0, 14, 20, 15, 7, 13, 26, 0, 25, 18, 6, 11, 13, 8, 21,
4, 20, 3, 17, 2, 29, 3, 12, 29, 3, 4, 15, 24, 20, 6, 14, 30, 22], :bech32}}
```
### SegwitAddr
#### Encoding a SegWit program into BIP-0350 format
```elixir
iex> SegwitAddr.encode("bc", "0014751e76e8199196d454941c45d1b3a323f1433bd6")
"bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4"
```
```elixir
iex> SegwitAddr.encode("bc", 0, [117, 30, 118, 232, 25, 145, 150, 212,
...> 84, 148, 28, 69, 209, 179, 163, 35, 241, 67, 59, 214])
"bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4"
```
#### Decoding a BIP-0350 Taproot address into a Tapscript program and formatting it as an hexadecimal ScriptPubKey
```elixir
iex> SegwitAddr.decode("bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4")
{:ok, {"bc", 0, [117, 30, 118, 232, 25, 145, 150, 212,
84, 148, 28, 69, 209, 179, 163, 35, 241, 67, 59, 214]}}
```
```elixir
iex> SegwitAddr.to_script_pub_key(0, [117, 30, 118, 232, 25, 145, 150,
...> 212, 84, 148, 28, 69, 209, 179, 163, 35, 241, 67, 59, 214])
"0014751e76e8199196d454941c45d1b3a323f1433bd6"
```
## Development
### Running tests
```bash
$ mix deps.get
$ mix test
```
### Running static analysis
This package uses Erlang's [dialyzer](http://erlang.org/doc/man/dialyzer.html) to find software discrepancies such as definite type errors, code which has become dead or unreachable due to some programming error, unnecessary tests, etc.
```bash
$ mix deps.get
$ mix dialyzer
```
## Credits
This project was forked from [stampery/elixir-bip0173](https://github.com/stampery/elixir-bip0173) and original code is copyrighted to Adán Sánchez de Pedro Crespo.
