Date: Sun, 29 Aug 2021 14:24:48 +0000
To: ts <ts@cronosurf.com>,
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
From: Pieter Wuille <bitcoin-dev@wuille.net>
Reply-To: Pieter Wuille <bitcoin-dev@wuille.net>
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Subject: Re: [bitcoin-dev] Human readable checksum (verification code) to
	avoid errors on BTC public addresses
Precedence: list

On Saturday, August 28th, 2021 at 5:17 PM, ts via bitcoin-dev <bitcoin-dev@=
lists.linuxfoundation.org> wrote:

> Following up on my original proposal, I would like to get some more feedb=
ack of the community
>
> to see if this could be realized at some point. Also, any recommendations=
 as to who to contact
>
> to get things rolling?

I honestly don't understand the point of what you're suggesting.

* If you're concerned about random typos, this is something already automat=
ically protected against through the checksum (both base58check or bech32/b=
ech32m).

* If you're concerned about accidentally entering the wrong - but honestly =
created - address, comparing any few characters of the address is just as g=
ood as any other. It doesn't even require the presence of a checksum. Looki=
ng at the last N characters, or the middle N, or anything except the first =
few, will do, and is just as good as an "external" checksum added at the en=
d. For randomly-generated addresses (as honest ones are), each of those has=
 exactly as much entropy.

* If you're concerned about maliciously constructed addresses, which are de=
signed to look similar in specific places, an attacker can just as easily m=
ake the external checksum collide (and having one might even worsen this, a=
s now the attacker can focus on exactly that, rather than needing to focus =
on every other character).

Things would be different if you'd suggest a checksum in another medium tha=
n text (e.g. a visual/drawing/colorcoding one). But I don't see any added v=
alue for an additional text-based checksum when addresses are already text =
themselves. This is even disregarding the difficulty of getting the ecosyst=
em to adopt such changes.

Cheers,

--
Pieter