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From: Pieter Wuille <bitcoin-dev@wuille.net>
To: ts <ts@cronosurf.com>,
	Bitcoin Protocol Discussion
	<bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Human readable checksum (verification code) to avoid errors on BTC public addresses
Date: Sun, 29 Aug 2021 14:42:07 +0000	[thread overview]
Message-ID: <ZJqjnpWzG9qKb0N02X9WLkBM2hRWk7w0hmAXlIuHj1bQZptdxVJzdVGXAwSPjkM187aRo5GkQq4oSnCurryxKRkWTeA5HgNL9VxmFMoTpF4=@wuille.net> (raw)
In-Reply-To: <8565f40b-2f32-cf31-6c47-971a6e57cb41@cronosurf.com>

On Thursday, August 19th, 2021 at 1:02 PM, ts via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:

> > In any case --- the last 5 characters of a bech32 string are already a human-readable 5-digit code, with fairly good properties, why is it not usable for this case?

Side note: it's actually the last six characters.

>
> Well, because
>
> a) most people don't know that
>
> b) it is specific to bech32
>
> c) it is not easily readable being the last digits of a long address (although this could be

I think this is a misconception. For the purpose of verifying that you have the *right* address (rather than just a valid one), the checksum, or even the knowledge that a checksum is present, is completely irrelevant.

In honestly-generated addresses, every character except the prefix (the ~2 first characters for P2PKH and P2SH, and the ~4 first characters for BIP173/BIP350 native segwit addresses) has exactly the same amount of entropy. Instead of adding say a 4 character code, just tell people to compare any 4 characters of their choosing. Or more - I would hope people are already comparing (much) more than 4 characters already.

It doesn't matter if the characters being compared are checksum characters or data characters. In honestly-generated addresses, both are equally random.

Adding a special 4 character "external" checksum IMO would instead encourage people to perhaps just compare those 4 characters instead of the rest (or at least, focus mostly on those). That could easily worsen how well comparisons are done in practice...

Cheers,

--
Pieter



  parent reply	other threads:[~2021-08-29 14:42 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-16  4:23 [bitcoin-dev] Human readable checksum (verification code) to avoid errors on BTC public addresses ts
2021-08-16 10:34 ` ZmnSCPxj
2021-08-19 17:02   ` ts
2021-08-19 17:37     ` Christopher Allen
2021-08-21  4:52       ` ts
2021-08-19 21:05     ` Karl
2021-08-21  4:52       ` ts
2021-08-29 14:42     ` Pieter Wuille [this message]
2021-08-31  2:17       ` ts
2021-08-28 21:17 ` ts
2021-08-29 14:24   ` Pieter Wuille
2021-08-31  2:16     ` ts
2021-08-31  8:47       ` Marek Palatinus
2021-09-03  5:08         ` ts

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