Add CombinedNonce() and RegisterCombinedNonce() methods with full implementation
stack.
Interface and core implementation:
- input/musig2.go: Added methods to MuSig2Session and MuSig2Signer interfaces
- input/musig2_session_manager.go: MusigSessionManager implementation using
HaveAllNonces flag for state tracking (simplified, no extra fields)
- internal/musig2v040: Stub implementations returning ErrUnsupportedMethod
- Mock implementations (MockInputSigner, MockSigner, DummySigner)
RPC layer:
- lnrpc/signrpc/signer.proto: RPC method definitions and messages
- lnrpc/signrpc/signer.yaml: REST API endpoint mappings
- Generated protobuf code (all .pb.go files)
- lnwallet/rpcwallet/rpcwallet.go: RPCKeyRing client implementation
The proto types and RPCKeyRing are added together since RPCKeyRing implements
the Signer interface and requires proto types to fulfill the contract.
For v0.4.0, these methods return ErrUnsupportedMethod. Use MuSig2Version100RC2
to access these features.
Since we explicitly keep an old version of a library in lnd for backward
compatibility we want to make sure the purpose and version of it is
clear and not misleading.
With this commit we copy the exact code of the MuSig2 code as found in
github.com/btcsuite/btcec/v2/schnorr/musig2 at the tag btcec/v2.2.2.
This corresponds to the MuSig2 BIP specification version of v0.4.0.
Elle Mouton