BIP-0322: clarify motivation/purpose, add prefix, clarify Proof of Funds format, describe PSBT based signing #2141

In commit "BIP-0322: add tentative changelog"

Final is a loaded term in context of the BIPs process. It used to refer to the status that we now call Deployed. Perhaps you could clarify whether you intend to move the BIP to Complete ("all planned work is done, and you are recommending it for adoption") or to Deployed ("all of the above, and at least one project is using it in production on mainnet"). This Changelog entry would then best be paired with the corresponding status change.

Yeah, you're right, changed to Complete.

“The list of UTXOs may or may not be related to the address being signed”

What “address” is this referring to? I thought BIP 322 message signing works by essentially creating a “fake” transaction where the list of inputs demonstrates control of UTXOs by providing valid inputs for the corresponding output scripts. I’m confused by the singular address vs UTXO list in this line.

The address is the pkScript you spend in the to_spend transaction, also called the message_challenge in the BIP. In the simple and full case, that's the single UTXO you spend with the fake transaction. In the proof of funds case, you can add more UTXOs, but those don't have to be related to the address. I clarified this in the latest update.

Could you please generally limit the length of any lines you add? Whitespace in the Mediawiki sourcecode doesn’t affect the rendering of the document, but GitHub stops highlighting the changed words after certain lengths:

<img width="982" height="145" alt="Image" src="https://github.com/user-attachments/assets/1759914b-8396-40ea-b5d6-a1782885f6d0" />

It is easier to parse what changed across commits when the text is composed of shorter lines, and it is also easier to provide suggestions in review comments. I would suggest a maximum text-width of 100 characters for the initial additions, and would request that diffs are minimized afterwards (i.e., when updating any line, allow for slightly shorter or longer lines over rebreaking or otherwise affecting untouched lines; for longer additions prefer inserting another line over changing linebreak of the following lines).

E.g., in the example below instead of moving "procedures" to the next line to make the first line adhere to the original length limit, which would make the diff appear bigger than it is, it’s kept in the same line to minimize the diff.

<img width="1031" height="172" alt="Image" src="https://github.com/user-attachments/assets/95b7db11-e202-42f2-aab2-009a1ba0ee59" />

Basically, please treat the document’s text like code! 🤓

Please Note that I’m not requesting that you reformat the entire existing document. Should you decide to do that, please make it a separate commit.

Hmm, yeah, I also don't like long lines. I remembered mediawiki being really weird when it comes to lists, so I didn't change the line length initially (I also try to match the code style of any project I contribute to). But shorter lines makes it much easier to work with text, I agree. So I added a commit at the beginning that does some formatting.

IMO the deeply nested lists don't become easier to read with this. So I opted for just keeping the long lines there for now. Let me know if you think it's worth changing those.

The alternative of course would be to move over to markdown completely. Which I'm not sure is a documented process?

Per BIP3, statuses are now one of Draft | Complete | Deployed | Closed.

The BIP status doesn't appear to be updated from Draft in this PR.

Right, added the change from Draft -> Complete now in the last commit and fixed the changelog.

This sounds like it warrants a Changelog entry. Could you please record the breaking change there?

You can find guidance about that in BIP3 here: https://github.com/bitcoin/bips/blob/master/bip-0003.md#changelog-section-and-version-header

I took a look at the comments wiki page. It just contains a couple questions and a link to this Bitcoin Talk discussion: https://bitcointalk.org/index.php?topic=5408898.l0.

I did not read the discussion, but if you find it interesting, you could add it as an entry to the "Discussion" header. You would then be free to drop the Comments headers as they are not required per BIP3 and the page doesn’t seem useful to me for this BIP.

You also need to update the background color in line 1075 (above) to

|- style="background-color: #cfffcf"

To clarify, that’s the cause of the CI failure.

cc: @achow101, no action required, just wanted to make you aware of this overlap with PSBTs, in case you had thoughts on PSBTs being used for Generic Message Signing.

BIP322 has been out there for nigh a decade and I think there are some implementations of it in production. From what I understand this update includes a breaking change to the format. While it was in Draft status and changes should still be expected, this may come as a surprise due to the age of the proposal. Therefore, I would request that you clearly document the breaking change in the Changelog and write to the mailing list about this update to BIP322.

When you start versioning the document per a Changelog section, please also add the Version header to the preamble!

Thanks for changing the formatting to shorter lines!

I am not sure what you mean about Mediawiki having issues with lists, I wasn’t aware, but if it helps, I wouldn’t have minded longer lines in lists. The HTML list syntax (…<ol><li>…) strikes me as more visual clutter in the source code compared to the Mediawiki syntax. It looks fine in the rendered document, though, so no need to change it again.