bech32

A BIP173/BIP350 compatible Bech32/Bech32m encoding/decoding library for Crystal.

Installation

1. Add the dependency to your shard.yml:

dependencies:
  bech32:
    github: wout/bech32

2. Run shards install

Usage

require "bech32"

Decoding

Decode using the default Bech32 encoding:

prefix, words = Bech32.decode("abcdef1qpzry9x8gf2tvdw0s3jn54khce6mua7lmqqqxw")
puts prefix
# => "abcdef"
puts words
# => Bytes[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31]

Decode using the Bech32M encoding:

prefix, words = Bech32.decode(
  "abcdef1l7aum6echk45nj3s0wdvt2fg8x9yrzpqzd3ryx",
  encoding: Bech32::Encoding::Bech32M
)
puts prefix
# => "abcdef"
puts words
# => Bytes[31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0]

To convert the words to bytes:

words = Bytes[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31]
Bech32.from_words(words)
# => Bytes[0, 68, 50, 20, 199, 66, 84, 182, 53, 207, 132, 101, 58, 86, 215, 198, 117, 190, 119, 223]

Encoding

Convert the string to words:

words = Bech32.to_words("foobar".to_slice)

Encode using the default Bech32 encoding:

Bech32.encode("foo", words)
# => "foo1vehk7cnpwgry9h96"

Encode using the Bech32M encoding:

Bech32.encode("foo", words, encoding: Bech32::Encoding::Bech32M)
# => "foo1vehk7cnpwgkc4mqc"

Advanced

BIP173 enforces a limitation of 90 characters. If the given string exceeds this length, pass a higher value using the limit argument. Be aware that the effectiveness of the checksum decreases as the length increases.

It is highly recommended not to exceed 1023 characters, as the module could only guarantee to detect one error.

Development

Make sure you have Guardian.cr installed. Then run:

$ guardian

This will automatically:

• run ameba for src and spec files
• run the relevant spec for any file in the src dir
• run spec a file whenever it's saved

Contributing

1. Fork it (https://github.com/wout/bech32/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Wout - creator and maintainer

Acknowledgments

This shard pulls inspiration from the following projects:

• bitcoinjs/bech32
• azuchi/bech32rb