# `Cartouche.Base58`
[🔗](https://github.com/zenhive/cartouche/blob/main/lib/cartouche/base58.ex#L1)

Base58 encoding and decoding using the Bitcoin/Solana alphabet.

This is plain Base58, NOT Base58Check (no version prefix or checksum).
Used by Solana for public keys (addresses) and transaction signatures.

If you `use Cartouche.Base58`, you get the `~B58` sigil for compile-time
Base58-to-binary decoding.

## Examples

    iex> Cartouche.Base58.encode(<<0, 0, 0>>)
    "111"

    iex> Cartouche.Base58.encode(<<0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x57, 0x6f, 0x72, 0x6c, 0x64, 0x21>>)
    "2NEpo7TZRRrLZSi2U"

    iex> Cartouche.Base58.decode("2NEpo7TZRRrLZSi2U")
    {:ok, "Hello World!"}

    iex> Cartouche.Base58.decode("abc0def")
    {:error, {:invalid_character, "0"}}

# `decode`

```elixir
@spec decode(String.t()) ::
  {:ok, binary()} | {:error, {:invalid_character, String.t()}}
```

Decode a Base58 string to a binary.

Returns `{:ok, binary}` on success, or `{:error, {:invalid_character, char}}` if the
string contains characters outside the Base58 alphabet.

## Examples

    iex> Cartouche.Base58.decode("")
    {:ok, <<>>}

    iex> Cartouche.Base58.decode("1")
    {:ok, <<0>>}

    iex> Cartouche.Base58.decode("2g")
    {:ok, <<0x61>>}

# `decode!`

```elixir
@spec decode!(String.t()) :: binary()
```

Decode a Base58 string to a binary, raising on invalid input.

## Examples

    iex> Cartouche.Base58.decode!("2g")
    <<0x61>>

# `encode`

```elixir
@spec encode(binary()) :: String.t()
```

Encode a binary to a Base58 string.

Each leading zero byte in the input produces a `"1"` character in the output.

## Examples

    iex> Cartouche.Base58.encode(<<>>)
    ""

    iex> Cartouche.Base58.encode(<<0>>)
    "1"

    iex> Cartouche.Base58.encode(<<0x61>>)
    "2g"

# `sigil_B58`
*macro* 

Handles the sigil `~B58` for compile-time Base58 decoding.

Decodes a Base58 string to binary at compile time, raising on
invalid input. Uses uppercase `B58` because Elixir multi-character
sigils require uppercase letters.

## Examples

    iex> use Cartouche.Base58
    iex> ~B58[11111111111111111111111111111111]
    <<0::256>>

    iex> use Cartouche.Base58
    iex> ~B58[TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA]
    <<6, 221, 246, 225, 215, 101, 161, 147, 217, 203, 225, 70, 206, 235, 121, 172, 28, 180, 133, 237, 95, 91, 55, 145, 58, 140, 245, 133, 126, 255, 0, 169>>

---

*Consult [api-reference.md](api-reference.md) for complete listing*
