Also covering Signmessage and BIP322
Generic signmessage is a method that allows wallets to sign or partially sign a message for any script from which they could conceivably spend.
The BIP322 generic signed message format allows a wallet to sign a text string in almost the same way the wallet would produce a signature for a Bitcoin transaction. This means a signed message can be produced for any script or address that a wallet would be able to spend. Additionally, two or more wallets can cooperate to create a BIP322 signed message for multisig scripts.
When signing for legacy P2PKH addresses, BIP322 instead uses the
signmessage format that was first implemented in an
early version of the Bitcoin software, making the proposal backwards
compatible with existing software that verifies signed messages for
Primary code and documentation
Optech newsletter and website mentions
- Simplified BIP322, only allowing signatures from one script per proof
- Proposed update to BIP322 generic signmessage
- Additional request for feedback on BIP322 generic signmessage