akovalenko / bech32

A library in Common Lisp for bech32 encoding and decoding

Bech32 encoding and decoding

Bech32 is an encoding used in modern bitcoin addresses described in BIP-0173.

Lightning Network invoices and LNURLs also use bech32. While it makes sense to limit total bech32 string length to 90 characters for bitcoin addresses, those other uses go beyond the limit, hence the library doesn't enforce it.

Functions:

• (encode hrp sequence) => string: provide bech32 string for a given human-readable part and a sequence of (MOD 32) elements.

• (decode string) => (values hrp vector): decode bech32, returning the human-readable part and the vector of (MOD 32) elements.

• (convert-bits sequence from to &optional pad) => vector: rearrange bits from from-sized to to-sized bytes, optionally padding the last element with zeroes (if pad is true) or checking that the leftover is zero (otherwise). Supports 8-to-5 bits or 5-to-8 bits conversion only. Depending on the thing you encode or decode, this function might be useful for pre/post processing your data or its parts (e.g. in bitcoin addresses, witness version is an isolated 5-bit number, while the rest of the address is really rearranged octets). See example.lisp for usage.