BIP373: Clarify where keys in MuSig fields may appear in the Taproot output #1695

1. 
   achow101 commented at 10:46 pm on November 6, 2024: member

   • The aggregate pubkey in PSBT_{IN,OUT}_MUSIG2_PARTICIPANT_PUBKEYS does not have to appear anywhere in the Taproot output.
   • The plain pubkeys in PSBT_IN_MUSIG2_PUB_NONCE and PSBT_IN_MUSIG2_PARTIAL_SIG must be either the output pubkey, or appears in a script, and not the internal key.
2. 
   achow101 commented at 10:46 pm on November 6, 2024: member

   cc @bigspider
3. lozanopo approved
4. jonatack added the label Proposed BIP modification on Nov 6, 2024
5. jonatack added the label Pending acceptance on Nov 6, 2024
6. jonatack removed the label Pending acceptance on Nov 6, 2024
7. 
   bigspider commented at 1:23 pm on November 7, 2024: contributor

   • The aggregate pubkey in PSBT_IN_MUSIG2_PUB_NONCE does not have to appear anywhere in the Taproot output.

   I think you meant PSBT_{IN,OUT}_MUSIG2_PARTICIPANT_PUBKEYS (clarifying for any other reader passing by)

8. in bip-0373.mediawiki:81 in 351aad6707 outdated

   76@@ -77,8 +77,8 @@ required for aggregation. If sorting was done, then the keys must be in the sort
   77 key the participant is providing the nonce for, followed by the BIP 341 tapleaf hash of
   78 the Taproot leaf script that will be signed. If the aggregate key is the taproot internal key or the
   79 taproot output key, then the tapleaf hash must be omitted. The plain public key must be
   80-the key found in the script and not the aggregate public key that it was derived from, if it was
   81-derived from an aggregate key.
   82+the output key or found in a script. It is not the internal key nor the aggregate public key that
   83+it was derived from, if it was derived from an aggregate key.
   

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   bigspider commented at 1:27 pm on November 7, 2024:

   Nit: The plain public key must be the taproot output key instead of The plain public key must be the output key, matching the language of BIP-341.

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   achow101 commented at 8:06 pm on November 7, 2024:

   Done
9. 
   bigspider commented at 1:28 pm on November 7, 2024: contributor

   ACK, only left a small nit to make it more explicit.
10. achow101 force-pushed on Nov 7, 2024
11. 
    achow101 commented at 8:06 pm on November 7, 2024: member

    I think you meant PSBT_{IN,OUT}_MUSIG2_PARTICIPANT_PUBKEYS (clarifying for any other reader passing by)

    Oops yes, fixed.

12. jonatack requested review from bigspider on Nov 8, 2024
13. in bip-0373.mediawiki:96 in 16be6ec090 outdated

    92@@ -93,8 +93,8 @@ derived from an aggregate key.
    93 plain public key the participant is providing the signature for, followed by the BIP 341 tapleaf hash
    94 of the Taproot leaf script that will be signed. If the aggregate key is the taproot internal key or
    95 the taproot output key, then the tapleaf hash must be omitted. Note that the plain public key must
    96-be the key found in the script and not the aggregate public key that it was derived from, if it was
    97-derived from an aggregate key.
    98+the taproot output key or found in a script. It is not the internal key nor the aggregate public key that
    

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    jonatack commented at 3:39 pm on November 8, 2024:

    Looks like a missing word here.

    “Note that the plain public key must…”

    0be the taproot output key or found in a script. It is not the internal key nor the aggregate public key that
    

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    achow101 commented at 4:43 pm on November 8, 2024:

    Fixed
14. bigspider approved
15. 
    bigspider commented at 4:41 pm on November 8, 2024: contributor

    LGTM, and it matches the way I implemented it as mentioned in #29675
16. 373: Clarify where keys in MuSig fields may appear in the Taproot output

    - The aggregate pubkey in `PSBT_{IN,OUT}_MUSIG2_PARTICIPANT_PUBKEYS` does not have to
      appear anywhere in the Taproot output.
    - The plain pubkeys in `PSBT_IN_MUSIG2_PUB_NONCE` and
      `PSBT_IN_MUSIG2_PARTIAL_SIG` must be either the output pubkey, or
      appears in a script, and not the internal key.

    0ff32bd4c2
17. achow101 force-pushed on Nov 8, 2024
18. 
    jonatack commented at 5:00 pm on November 8, 2024: member

    ACK 0ff32bd4c274a83d5a10c23afeab9280a25799e4
19. jonatack renamed this:
    373: Clarify where keys in MuSig fields may appear in the Taproot output
    BIP373: Clarify where keys in MuSig fields may appear in the Taproot output
    on Nov 8, 2024
20. jonatack merged this on Nov 8, 2024
21. jonatack closed this on Nov 8, 2024

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Contributors
achow101 lozanopo bigspider jonatack

Labels
Proposed BIP modification