fix: implement BIP341 key tweaking for P2TR transaction signing

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This commit fixes P2TR (Pay-to-Taproot) transaction signing by properly
implementing BIP341 key path spending.

Key changes:
- Add SignSchnorrTaproot() method to CKey for BIP341 tweaked signing
- Implement ComputeTapTweak() and CreatePayToTaprootPubKey() in XOnlyPubKey
- Add GetTaprootInternalKey() to SigningProvider interface for internal key lookup
- Store taproot internal key mappings in LegacyScriptPubKeyMan
- Fix FindTaprootPubKey() to use internal key mapping with fallback
- Use empty scriptCode for Taproot key-path spending (per BIP341 spec)
- Update HaveTaprootKey() to verify tweaked keys correctly

Technical details:
- Internal keys are tweaked using secp256k1_keypair_xonly_tweak_add
- Parity handling is automatic via secp256k1 library
- Empty scriptCode ensures correct sighash for key-path spending
- Internal key to output key mapping stored for efficient lookup

Testing:
- P2TR address creation, funding, and spending work end-to-end
- Multi-hop P2TR transactions tested successfully
- All functional tests pass (feature_taproot.py, wallet_*, rpc_*)

Fixes: non-mandatory-script-verify-flag error on P2TR spending

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This commit is contained in:

Davide Grilli

2026-02-08 00:55:02 +01:00

parent aee82dfad1

commit ac6ae69329

18 changed files with 319 additions and 19 deletions

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test/functional/test_runner.py Normal file → Executable file