📅 Original date posted:2022-07-26
📝 Original message:Thanks Andrew for this BIP. We've been already using this for quite some
time for Trezor in production.
Just one clarification: Should <NUM;NUM;NUM>, <NUM;NUM;NUM;NUM>, ... also
work or we only aim to support only tuples of exactly two values?
On Tue, 26 Jul 2022 at 23:51, Andrew Chow via bitcoin-dev <
bitcoin-dev at lists.linuxfoundation.org> wrote:
> Hi All,
>
> I would like to propose a BIP that de-duplicates and simplifies how we
> represent descriptors for receiving and change addresses. Under the
> existing BIPs, this requires two descriptors, where the vast majority of
> the descriptors are the same, except for a single derivation path
> element. This proposal allows descriptors to have a single derivation
> path element that can specify a pair of indexes. Parsers would then
> expand these into two almost identical descriptors with the difference
> being that the first uses the first of the pair of indexes, and the
> second uses the second.
>
> The proposed notation is `<a;b>`. As an example,
> `wpkh(xpub.../0/<0;1>/*)` would be expanded into `wpkh(xpub.../0/0/*)`
> and `wpkh(xpub.../0/1/*)`.
>
> This also works for descriptors involving multiple keys - the first
> element in every pair is used for the first descriptor, and the second
> element of each pair in the second descriptor.
>
> The full text of the BIP can be found at
>
> https://github.com/achow101/bips/blob/bip-multipath-descs/bip-multipath-descs.mediawiki
> and also copied below. An implementation of it to Bitcoin Core is
> available at https://github.com/bitcoin/bitcoin/pull/22838.
>
> Any feedback on this would be appreciated.
>
> Thanks,
> Andrew Chow
>
> ---
>
> <pre>
> BIP: multipath-descs
> Layer: Applications
> Title: Multipath Descriptor Key Expressions
> Author: Andrew Chow <andrew at achow101.com>
> Comments-Summary: No comments yet.
> Comments-URI:
> https://github.com/bitcoin/bips/wiki/Comments:BIP-multipath-descs
> Status: Draft
> Type: Informational
> Created: 2022-07-26
> License: BSD-2-Clause
> </pre>
>
> ==Abstract==
>
> This document specifies a modification to Key Expressions of Descriptors
> that are described in BIP 380.
> This modification allows Key Expressions to indicate BIP 32 derivation
> path steps that can have multiple values.
>
> ==Copyright==
>
> This BIP is licensed under the BSD 2-clause license.
>
> ==Motivation==
>
> Descriptors can describe the scripts that are used in a wallet, but
> wallets often require at least two descriptors for all of the scripts
> that they watch for.
> Wallets typically have one descriptor for producing receiving addresses,
> and the other for change addresses.
> These descriptors are often extremely similar - they produce the same
> types of scripts, derive keys from the same master key, and use
> derivation paths that are almost identical.
> The only differences are in the derivation path where one of the steps
> will be different between the descriptors.
> Thus it is useful to have a notation to represent both descriptors as a
> single descriptor where one of the derivation steps is a pair of values.
>
> ==Specification==
>
> For extended keys and their derivations paths in a Key Expression, BIP
> 380 states:
>
> * <tt>xpub</tt> encoded extended public key or <tt>xprv</tt> encoded
> extended private key (as defined in BIP 32)
> ** Followed by zero or more <tt>/NUM</tt> or <tt>/NUMh</tt> path
> elements indicating BIP 32 derivation steps to be taken after the given
> extended key.
> ** Optionally followed by a single <tt>/*</tt> or <tt>/*h</tt> final
> step to denote all direct unhardened or hardened children.
>
> This is modifed to state:
>
> * <tt>xpub</tt> encoded extended public key or <tt>xprv</tt> encoded
> extended private key (as defined in BIP 32)
> ** Followed by zero or more <tt>/NUM</tt> or <tt>/NUMh</tt> path
> elements indicating BIP 32 derivation steps to be taken after the given
> extended key.
> ** Followed by zero or one <tt>/<NUM;NUM></tt> (<tt>NUM</tt> may be
> followed by <tt>h</tt> to indicated a hardened step) path element
> indicating a pair of BIP 32 derivation steps to be taken after the given
> extended key.
> ** Followed by zero or more <tt>/NUM</tt> or <tt>/NUMh</tt> path
> elements indicating BIP 32 derivation steps to be taken after the given
> extended key.
> ** Optionally followed by a single <tt>/*</tt> or <tt>/*h</tt> final
> step to denote all direct unhardened or hardened children.
>
> When a <tt>/<NUM;NUM></tt> is encountered, parsers should produce two
> descriptors where the first descriptor uses the first <tt>NUM</tt>, and
> a second descriptor uses the second <tt>NUM</tt>.
>
> The common use case for this is to represent descriptors for producing
> receiving and change addresses.
> When interpreting for this use case, wallets should use the first
> descriptor for producing receiving addresses, and the second descriptor
> for producing change addresses.
> For this use case, the element will commonly be the value <tt>/<0;1></tt>
>
> ==Test Vectors==
>
> TBD
>
> ==Backwards Compatibility==
>
> This is an addition to the Key Expressions defined in BIP 380.
> Key Expressions using the format described in BIP 380 are compatible
> with this modification and parsers that implement this will still be
> able to parse such descriptors.
> However as this is an addition to Key Expressions, older parsers will
> not be able to understand such descriptors.
>
> This modification to Key Expressions uses two new characters: <tt><</tt>
> and <tt>;</tt>.
> These are part of the descriptor character set and so are covered by the
> checksum algorithm.
> As these are previously unused characters, old parsers will not
> accidentally mistake them for indicating something else.
>
> ==Reference Implementation==
>
> https://github.com/bitcoin/bitcoin/pull/22838
>
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev at lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
--
Best Regards / S pozdravom,
Pavol "stick" Rusnak
Co-Founder, SatoshiLabs
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20220726/cef0a54a/attachment-0001.html>;
Pavol Rusnak [ARCHIVE] /
npub1wc…3hnuq
2023-06-08 01:12:15
in reply to nevent1q…mkux
Author Public Key
npub1wccnjljxnarlx564vuc37hmuzuffurljevjnmuq4u0vjmh7e933sn3hnuqPublished at
2023-06-08 01:12:15Event JSON
{
"id": "5ce19cfd7ffc0b4fe39125b0acb5bd798b1698fcfc059826c8592d66da509254",
"pubkey": "7631397e469f47f3535567311f5f7c17129e0ff2cb253df015e3d92ddfd92c63",
"created_at": 1686179535,
"kind": 1,
"tags": [
[
"e",
"4bbeff45fe327dd8a25e73531abd515e2a94cabab69a434340c764e33537b7b4",
"",
"root"
],
[
"e",
"9176a424919a4a68ae104eaccc13e1a449a15ce783e0bfe4cfbcb73c9837b669",
"",
"reply"
],
[
"p",
"4a273da3c9ab85c096f859e6ca066d2fdfe762406cadc2f4d58aa75468aca8d0"
]
],
"content": "📅 Original date posted:2022-07-26\n📝 Original message:Thanks Andrew for this BIP. We've been already using this for quite some\ntime for Trezor in production.\n\nJust one clarification: Should \u003cNUM;NUM;NUM\u003e, \u003cNUM;NUM;NUM;NUM\u003e, ... also\nwork or we only aim to support only tuples of exactly two values?\n\nOn Tue, 26 Jul 2022 at 23:51, Andrew Chow via bitcoin-dev \u003c\nbitcoin-dev at lists.linuxfoundation.org\u003e wrote:\n\n\u003e Hi All,\n\u003e\n\u003e I would like to propose a BIP that de-duplicates and simplifies how we\n\u003e represent descriptors for receiving and change addresses. Under the\n\u003e existing BIPs, this requires two descriptors, where the vast majority of\n\u003e the descriptors are the same, except for a single derivation path\n\u003e element. This proposal allows descriptors to have a single derivation\n\u003e path element that can specify a pair of indexes. Parsers would then\n\u003e expand these into two almost identical descriptors with the difference\n\u003e being that the first uses the first of the pair of indexes, and the\n\u003e second uses the second.\n\u003e\n\u003e The proposed notation is `\u003ca;b\u003e`. As an example,\n\u003e `wpkh(xpub.../0/\u003c0;1\u003e/*)` would be expanded into `wpkh(xpub.../0/0/*)`\n\u003e and `wpkh(xpub.../0/1/*)`.\n\u003e\n\u003e This also works for descriptors involving multiple keys - the first\n\u003e element in every pair is used for the first descriptor, and the second\n\u003e element of each pair in the second descriptor.\n\u003e\n\u003e The full text of the BIP can be found at\n\u003e\n\u003e https://github.com/achow101/bips/blob/bip-multipath-descs/bip-multipath-descs.mediawiki\n\u003e and also copied below. An implementation of it to Bitcoin Core is\n\u003e available at https://github.com/bitcoin/bitcoin/pull/22838.\n\u003e\n\u003e Any feedback on this would be appreciated.\n\u003e\n\u003e Thanks,\n\u003e Andrew Chow\n\u003e\n\u003e ---\n\u003e\n\u003e \u003cpre\u003e\n\u003e BIP: multipath-descs\n\u003e Layer: Applications\n\u003e Title: Multipath Descriptor Key Expressions\n\u003e Author: Andrew Chow \u003candrew at achow101.com\u003e\n\u003e Comments-Summary: No comments yet.\n\u003e Comments-URI:\n\u003e https://github.com/bitcoin/bips/wiki/Comments:BIP-multipath-descs\n\u003e Status: Draft\n\u003e Type: Informational\n\u003e Created: 2022-07-26\n\u003e License: BSD-2-Clause\n\u003e \u003c/pre\u003e\n\u003e\n\u003e ==Abstract==\n\u003e\n\u003e This document specifies a modification to Key Expressions of Descriptors\n\u003e that are described in BIP 380.\n\u003e This modification allows Key Expressions to indicate BIP 32 derivation\n\u003e path steps that can have multiple values.\n\u003e\n\u003e ==Copyright==\n\u003e\n\u003e This BIP is licensed under the BSD 2-clause license.\n\u003e\n\u003e ==Motivation==\n\u003e\n\u003e Descriptors can describe the scripts that are used in a wallet, but\n\u003e wallets often require at least two descriptors for all of the scripts\n\u003e that they watch for.\n\u003e Wallets typically have one descriptor for producing receiving addresses,\n\u003e and the other for change addresses.\n\u003e These descriptors are often extremely similar - they produce the same\n\u003e types of scripts, derive keys from the same master key, and use\n\u003e derivation paths that are almost identical.\n\u003e The only differences are in the derivation path where one of the steps\n\u003e will be different between the descriptors.\n\u003e Thus it is useful to have a notation to represent both descriptors as a\n\u003e single descriptor where one of the derivation steps is a pair of values.\n\u003e\n\u003e ==Specification==\n\u003e\n\u003e For extended keys and their derivations paths in a Key Expression, BIP\n\u003e 380 states:\n\u003e\n\u003e * \u003ctt\u003expub\u003c/tt\u003e encoded extended public key or \u003ctt\u003exprv\u003c/tt\u003e encoded\n\u003e extended private key (as defined in BIP 32)\n\u003e ** Followed by zero or more \u003ctt\u003e/NUM\u003c/tt\u003e or \u003ctt\u003e/NUMh\u003c/tt\u003e path\n\u003e elements indicating BIP 32 derivation steps to be taken after the given\n\u003e extended key.\n\u003e ** Optionally followed by a single \u003ctt\u003e/*\u003c/tt\u003e or \u003ctt\u003e/*h\u003c/tt\u003e final\n\u003e step to denote all direct unhardened or hardened children.\n\u003e\n\u003e This is modifed to state:\n\u003e\n\u003e * \u003ctt\u003expub\u003c/tt\u003e encoded extended public key or \u003ctt\u003exprv\u003c/tt\u003e encoded\n\u003e extended private key (as defined in BIP 32)\n\u003e ** Followed by zero or more \u003ctt\u003e/NUM\u003c/tt\u003e or \u003ctt\u003e/NUMh\u003c/tt\u003e path\n\u003e elements indicating BIP 32 derivation steps to be taken after the given\n\u003e extended key.\n\u003e ** Followed by zero or one \u003ctt\u003e/\u003cNUM;NUM\u003e\u003c/tt\u003e (\u003ctt\u003eNUM\u003c/tt\u003e may be\n\u003e followed by \u003ctt\u003eh\u003c/tt\u003e to indicated a hardened step) path element\n\u003e indicating a pair of BIP 32 derivation steps to be taken after the given\n\u003e extended key.\n\u003e ** Followed by zero or more \u003ctt\u003e/NUM\u003c/tt\u003e or \u003ctt\u003e/NUMh\u003c/tt\u003e path\n\u003e elements indicating BIP 32 derivation steps to be taken after the given\n\u003e extended key.\n\u003e ** Optionally followed by a single \u003ctt\u003e/*\u003c/tt\u003e or \u003ctt\u003e/*h\u003c/tt\u003e final\n\u003e step to denote all direct unhardened or hardened children.\n\u003e\n\u003e When a \u003ctt\u003e/\u003cNUM;NUM\u003e\u003c/tt\u003e is encountered, parsers should produce two\n\u003e descriptors where the first descriptor uses the first \u003ctt\u003eNUM\u003c/tt\u003e, and\n\u003e a second descriptor uses the second \u003ctt\u003eNUM\u003c/tt\u003e.\n\u003e\n\u003e The common use case for this is to represent descriptors for producing\n\u003e receiving and change addresses.\n\u003e When interpreting for this use case, wallets should use the first\n\u003e descriptor for producing receiving addresses, and the second descriptor\n\u003e for producing change addresses.\n\u003e For this use case, the element will commonly be the value \u003ctt\u003e/\u003c0;1\u003e\u003c/tt\u003e\n\u003e\n\u003e ==Test Vectors==\n\u003e\n\u003e TBD\n\u003e\n\u003e ==Backwards Compatibility==\n\u003e\n\u003e This is an addition to the Key Expressions defined in BIP 380.\n\u003e Key Expressions using the format described in BIP 380 are compatible\n\u003e with this modification and parsers that implement this will still be\n\u003e able to parse such descriptors.\n\u003e However as this is an addition to Key Expressions, older parsers will\n\u003e not be able to understand such descriptors.\n\u003e\n\u003e This modification to Key Expressions uses two new characters: \u003ctt\u003e\u003c\u003c/tt\u003e\n\u003e and \u003ctt\u003e;\u003c/tt\u003e.\n\u003e These are part of the descriptor character set and so are covered by the\n\u003e checksum algorithm.\n\u003e As these are previously unused characters, old parsers will not\n\u003e accidentally mistake them for indicating something else.\n\u003e\n\u003e ==Reference Implementation==\n\u003e\n\u003e https://github.com/bitcoin/bitcoin/pull/22838\n\u003e\n\u003e\n\u003e _______________________________________________\n\u003e bitcoin-dev mailing list\n\u003e bitcoin-dev at lists.linuxfoundation.org\n\u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\n\u003e\n\n\n-- \nBest Regards / S pozdravom,\n\nPavol \"stick\" Rusnak\nCo-Founder, SatoshiLabs\n-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20220726/cef0a54a/attachment-0001.html\u003e",
"sig": "7edf05c57397cb66b7f5187ed1b4e6ae0a3442cb8aa002c069cf038653b4d01a1cee8c8a249856f2551e1761330d8af945a28574c7fc36065b8e728ea5777414"
}