From: nakagat <nakagat@gmail•com>
To: Pieter Wuille <bitcoin-dev@wuille•net>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Bech32m BIP: new checksum, and usage for segwit address
Date: Mon, 18 Jan 2021 14:59:05 +0900 [thread overview]
Message-ID: <CAHk9a9egxmTQqSLs9PUuH1L8q_c7hp_oo4jT1+BP0ga=aFCPhQ@mail.gmail.com> (raw)
In-Reply-To: <N9ny4XfpI4SATvCXSKO_ns03ONm4p17tAGXxInoXIe16S7zfH6b8Uj2SkS-pL5sEEp7Wpyi0RZ8J92WZPDeHYKBBuq1xnV6eEUbKouej-TU=@wuille.net>
Dear. Peter,
I'm not good at English, so I'm sorry for the poor explanation.
I thought that BECH32M_CONST could be created from hrp and data
instead of constants.
I thought that the error position would be the same as bech32 by
recalculating the value created from hrp and data.
If this were possible, I thought I could commit hrp and data to the checksum.
Thank you.
Takatoshi Nakagawa
2021年1月18日(月) 13:15 Pieter Wuille <bitcoin-dev@wuille•net>:
>
> Hi all,
>
> A few updates, in response to comments here and in a few other places:
>
> - Updated several reference implementations (C, C++, Python, Javascript) to support Bech32m: https://github.com/sipa/bech32/tree/bech32m (but contributions to update other languages are welcome!)
>
> - Updated website, including error-locating JS decoder, and demo: http://bitcoin.sipa.be/bech32/demo/demo.html
>
> - Opened a Bitcoin Core PR: https://github.com/bitcoin/bitcoin/pull/20861
>
> - Updates to the BIP draft (https://github.com/sipa/bips/blob/bip-bech32m/bip-bech32m.mediawiki):
> * Made the title clearer (so it doesn't imply Bech32m is used for v0)
> * Added rationale for not permitting both Bech32 and Bech32m for v0
> * Added a section on error location
> * Added links for more reference implementations
>
> On Friday, January 15, 2021 12:01 AM, nakagat <nakagat@gmail•com> wrote:
>
> > I read the BIP draft of Bech32m and implemented it in Go.
>
> Cool! Do feel like contributing it to https://github.com/sipa/bech32/tree/bech32m?
>
> > Let me ask you one question.
> > Does Checksum have to be fixed?
> > The 'bech32_verify_checksum' function has hrp and data as parameters,
> > so how about committing Checksum with these two values?
> >
> > For example, calculate Checksum from hrp and data using hash, chacha20, etc.
>
> I'm not entirely sure what you mean. Do you mean:
>
> 1) Can we use a hash function to compute the checksum instead of Bech32's algorithm?
>
> If you compute the checksum using the HRP and the data using a hash function, you just 2^-30 failure probability for any error. The idea behind Bech32 was doing better than that for common errors: any error that consists of up to 4 substitutions are a failure probability of 0 - far better than a hash can do.
>
> 2) Can we keep using Bech32's algorithm, but compute the final xorred-in constant from the HRP and the data using a hash function?
>
> That would be functionally equivalent to (1).
>
> 3) Can we keep using Bech32's algorithm, but compute the final xorred-in constant from the HRP (but not the data) using a hash function?
>
> It would mean that some (very) small set of potential HRPs would exhibit much worse behavior than others - including the 'q'-before-'p' that the original Bech32 has.
>
> Does that clarify things?
>
> Cheers,
>
> --
> Pieter
>
next prev parent reply other threads:[~2021-01-18 5:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-05 0:14 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 [this message]
2021-01-19 17:57 ` Pieter Wuille
[not found] ` <CAHk9a9crrQJFUZ5EcBUfz5QCdxHzgTiN1b9_ocfMgf4Qhx98Pw@mail.gmail.com>
2021-01-20 0:29 ` Pieter Wuille
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