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psbt: add MuSig2 fields#784

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achow101 merged 1 commit intobitcoin-core:masterfrom
Sjors:2025/06/psbt
Feb 3, 2026
Merged

psbt: add MuSig2 fields#784
achow101 merged 1 commit intobitcoin-core:masterfrom
Sjors:2025/06/psbt

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@Sjors Sjors commented Jun 3, 2025 •
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Fixes #783

@Sjors Sjors force-pushed the 2025/06/psbt branch 2 times, most recently from fc57dfb to 46ceff9 Compare June 3, 2025 07:44
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Sjors commented Jun 3, 2025

This should be useful: https://github.com/LedgerHQ/app-bitcoin-new/blob/master/bitcoin_client/ledger_bitcoin/psbt.py

@Sjors Sjors marked this pull request as ready for review June 4, 2025 09:56
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Sjors commented Jun 4, 2025 •
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I ended copying @bigspider's code. However there's no test coverage.

I also can't manually test it on a device without passing the BIP-388 policy policy and (no BIP?) HMAC, which is a separate issue.

@Sjors Sjors mentioned this pull request Jul 21, 2025
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Sjors commented Jul 21, 2025

Fixed a few bugs.

I wanted to test this using #792 and taking some code from MooSig, but the latter changed the sign_psbt signature to return List[Tuple[int, SignPsbtYieldedObject]] instead of List[Tuple[int, bytes, bytes]].

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Sjors commented Jul 21, 2025 •
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I think I get the gist of the sign_psbt change, so I made a standalone change in #793 use the SignPsbtYieldedObject (only PartialSignature, leaving out the MuSig2 specific MusigPubNonce and MusigPartialSignature).

@Sjors Sjors mentioned this pull request Jul 21, 2025
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Sjors commented Jul 30, 2025

I've been testing this with various wallets and I'm pretty sure it works now.

Rebasing on #795 to make sure CI passes.

@Sjors Sjors force-pushed the 2025/06/psbt branch 2 times, most recently from f35fe9f to 337fd14 Compare July 30, 2025 12:05
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Sjors commented Jul 30, 2025

Fixed linter E226 missing whitespace around arithmetic operator

Looks like I accidentally dropped PSBT_IN_TAP_INTERNAL_KEY deserialization code bit, brought it back.

I also added the new test vectors, copied from Bitcoin Core.

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Sjors commented Sep 4, 2025

Rebased after #795 landed.

achow101
achow101 reviewed Jan 30, 2026
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hwilib/psbt.py Outdated
r += ser_string(b''.join(pubkeys))

for (pk, aggpk, hash), pubnonce in self.musig2_pub_nonces.items():
key_value = pk + aggpk + (hash or b'')
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hash is the name of a builtin function in python, we should avoid naming variables hash.

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@Sjors Sjors Jan 31, 2026

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Fixed and rebased.

@Sjors @bigspider
psbt: add MuSig2 fields
351b3e4 
Co-Authored-By: Salvatore Ingala <6681844+bigspider@users.noreply.github.com>
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achow101 commented Feb 3, 2026

ACK 351b3e4

@achow101 achow101 merged commit 8e72d66 into bitcoin-core:master Feb 3, 2026
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Add MuSig2 PSBT fields

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