Add sp() output descriptor format for BIP352 Silent Payments #2047

1. 
   craigraw commented at 11:13 am on December 3, 2025: contributor

   This builds on and provides an alternative to #2026, which references an earlier discussion. Instead of modifying BIP352, a new output descriptor format is proposed in the style of BIPs 381-387.

   Similar to #2026 key expressions starting with spscan and spspend are specified, but contain only version and key material information. The wallet birthday and additional labels are specified as optional additional arguments in the output descriptor format.

   BIP352 authors: @josibake @RubenSomsen

   Mail list discussion: https://groups.google.com/g/bitcoindev/c/bP6ktUyCOJI

2. Add sp() output descriptor format for BIP352 Silent Payments 9557c1e2f6
3. jonatack added the label New BIP on Dec 3, 2025
4. in bip-spdescriptor.mediawiki:12 in 9557c1e2f6

    7+  Comments-URI: TBD
    8+  Status: Draft
    9+  Type: Informational
   10+  Created: 2025-12-03
   11+  License: BSD-2-Clause
   12+  Requires: 352, 380
   

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   jonatack commented at 7:59 pm on December 3, 2025:

   Maybe add 44, 341, 350
5. in bip-spdescriptor.mediawiki:11 in 9557c1e2f6 outdated

    6+  Comments-Summary: No comments yet.
    7+  Comments-URI: TBD
    8+  Status: Draft
    9+  Type: Informational
   10+  Created: 2025-12-03
   11+  License: BSD-2-Clause
   

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   jonatack commented at 8:06 pm on December 3, 2025:

   Between the License and the Requires headers, could add:

   Post-History: <link to mailing list post>

6. 
   jonatack commented at 8:09 pm on December 3, 2025: member

   Looks sound and high quality for an initial draft. I don’t see the BIP 2 specified mail list discussion for this proposal?
7. Update headers and remove space after comma in descriptors 6807d2f4ef
8. 
   craigraw commented at 8:56 am on December 4, 2025: contributor

   Thanks for the reminder - I’ve sent the mailing list post and added the link in the BIP. Also, the spaces after commas in the descriptors have been removed to be consistent with BIP 380-387.
9. 
   pythcoiner commented at 10:26 am on December 4, 2025: none

   Thanks for working on this! Overall lgtm, the only comment I have is, maybe a way to specify a label range could be useful?
10. 
    craigraw commented at 11:13 am on December 4, 2025: contributor

    Overall lgtm, the only comment I have is, maybe a way to specify a label range could be useful?

    I’m not strongly opposed to this, but given the cost of scanning for each additional label I’m reluctant to add it - it may make a wallet synchronization trivially impractical in a non-obvious way simply by accidentally specifying a large range.

11. 
    pythcoiner commented at 1:01 pm on December 4, 2025: none

    Maybe with adding a note discouraging wallet to export a range? I mainly see range usefull for exchanges that can have a wide range, but also for this special case I guess they also need to backup associate metada for each label, so the descriptor is not sufficient anyway…

Contributors
craigraw jonatack pythcoiner

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