bech32(1) for encoding/decoding of Bech32 strings & “Bravo Charlie” Addresses

I have released an initial version of the bech32(1) utility for encoding and decoding of BIP 173 Bech32 strings and Bitcoin Bravo Charlie Addresses (bc1). As any worthwhile software, it comes replete with a manpage (text), q.v.

As part of its initial feature set, bech32(1) has special handling for RFC 7686 .onion special-use domain names; it detects such a name, and transcodes the RFC 4648 Base32 to and from Bech32 with an HRP of onion. For Bitcoin Bravo Charlie addresses, bech32(1) takes and gives the witness version and the hexadecimal-coded octets of the witness program. Otherwise, for the most part, it encodes and decodes hexadecimal data with user-provided HRPs. I intend to add special interpretation of pgp1 with a concept I call PGP Descriptors; but I need to spec that out first.

Some usage examples from the manpage:

Code:

Extract the witness version and Hash160 from the bech32 utility author's
Bech32 tip address:

   bech32 -S bc1qcash96s5jqppzsp8hy8swkggf7f6agex98an7h
   0:0xc76172ea149002114027b90f0759084f93aea326

Get a hello, world introduction to Bech32:

   bech32 -e -h hello_world 48656c6c6f2c20776f726c6421
   hello_world1fpjkcmr09ss8wmmjd3jzzwhs4ff

Generate a burn address with a Hash160 of all zeroes, which would be
spendable by the same unknown private keys as the infamous
1111111111111111111114oLvT2. Warning: Do NOT send coins here:

   bech32 -s 0 0x0000000000000000000000000000000000000000
   bc1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq9e75rs

Bech32-encode the address for Wikileaks, to add error-correcting codes:

   bech32 -e wlupld3ptjvsgwqw.onion
   onion1kt50trm0nf4jxkskpcjy74

Now, decode the address someone gave you:

   bech32 -d onion1kt50trm0nf4jxkskpcjy74
   wlupld3ptjvsgwqw.onion

Licensing includes a Bitcoin Consensus Clause, to prevent use by scamcoin pretenders.

This is an alpha-quality initial release. The code is still a bit messy; it needs test vectors, which seem insufficiently specified; features and the finer details of behaviour may be a bit in flux. However, the basic user interface should be considered stable. I am here opening a Bitcoin Forum thread for discussion of this utility; over time, I will edit and update this post as appropriate.