[tor-dev] Error-Correcting Onions with Bech32

[Taylor R Campbell]

> Date: Sun, 31 Dec 2017 11:46:28 +0000
> From: Alec Muffett <alec.muffett at gmail.com>
> 
> Or, indeed, you could leave out the hyphens and do the same; the Prop224
> Onion address is 59 characters, leaving a budget of 63-59==4 characters or
> 20 bits; we could put these at the end, in the space marked "@@@@":
> 
>   https://www4acth47i6kxnvkewtm6q7ib2s3ufpo5sqbsnzjpbi7utijcltosqemad@@@@.onion/

Existing checksum in v3 addresses aside, what would prevent using a
second DNS label for a longer checksum if you wanted a bigger budget?

The labels are limited to 63 octets, but the whole name can be up to
255 (including label length bytes).