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

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.

achow101 commented at 10:46 PM on November 6, 2024: member

cc @bigspider

lozanopo approved

jonatack added the label Proposed BIP modification on Nov 6, 2024

jonatack added the label Pending acceptance on Nov 6, 2024

jonatack removed the label Pending acceptance on Nov 6, 2024

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)

in bip-0373.mediawiki:81 in 351aad6707 outdated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

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.

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

Done

bigspider commented at 1:28 PM on November 7, 2024: contributor

ACK, only left a small nit to make it more explicit.

achow101 force-pushed on Nov 7, 2024

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.

jonatack requested review from bigspider on Nov 8, 2024

in bip-0373.mediawiki:96 in 16be6ec090 outdated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

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

Looks like a missing word here.

"Note that the plain public key must..."

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

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

Fixed

bigspider approved

bigspider commented at 4:41 PM on November 8, 2024: contributor

LGTM, and it matches the way I implemented it as mentioned in #29675

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

achow101 force-pushed on Nov 8, 2024

jonatack commented at 5:00 PM on November 8, 2024: member

ACK 0ff32bd4c274a83d5a10c23afeab9280a25799e4

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

jonatack merged this on Nov 8, 2024

jonatack closed this on Nov 8, 2024