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From: Pieter Wuille <bitcoin-dev@wuille.net>
To: nakagat <nakagat@gmail.com>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Bech32m BIP: new checksum, and usage for segwit address
Date: Wed, 20 Jan 2021 00:29:36 +0000	[thread overview]
Message-ID: <WbHmWTdrVtO8kbI3xfn9S7-g8zruzRt_hngpxvJQWC0ibNSNMWXo3I1gjt9vzhF53pRbh-14VjPcA1JKckgaogi-fu3F48Yfwqmm2rX8K8g=@wuille.net> (raw)
In-Reply-To: <CAHk9a9crrQJFUZ5EcBUfz5QCdxHzgTiN1b9_ocfMgf4Qhx98Pw@mail.gmail.com>

On Tuesday, January 19, 2021 4:23 PM, nakagat <nakagat@gmail.com> wrote:

> Dear. Pieter,
>
> My idea is exactly what you wrote.
>
> However, I don't think it is the same as "checksum = hash (hrp, data)".

No, it is not the same. But it has the same error-detection properties as just a hash. Hash-based checksums aren't bad, but:
* The BCH based checksum that Bech32 uses is better at detecting certain subsets of errors than a hash can be. Once you add in a hash you irrevocably lose these properties.
* If we wanted a checksum with error detection properties that are equivalent to a hash, we should just use a hash like Base58Check did. However, that's not the goal of Bech32/Bech32m.

If this isn't clear, I'm afraid I don't know how to continue discussing this. We can take if off this list, if you want.

Cheers,

--
Pieter



      parent reply	other threads:[~2021-01-20  0:29 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-05  0:14 [bitcoin-dev] Bech32m BIP: new checksum, and usage for segwit address Pieter Wuille
2021-01-05  1:25 ` Pieter Wuille
2021-01-09  5:00   ` Rusty Russell
2021-01-15  8:01 ` nakagat
2021-01-18  4:15   ` Pieter Wuille
2021-01-18  5:59     ` nakagat
2021-01-19 17:57       ` Pieter Wuille
     [not found]         ` <CAHk9a9crrQJFUZ5EcBUfz5QCdxHzgTiN1b9_ocfMgf4Qhx98Pw@mail.gmail.com>
2021-01-20  0:29           ` Pieter Wuille [this message]

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