Patching SeedSigner to Support Multisig Message Signing
I run CertainKey, a service that provides ownership and control verification reports for self-managed super funds (SMSFs) holding bitcoin. Part of that process involves proving that the fund trustee controls specific keys in a multisig wallet — not by moving funds, but by signing a message with each key individually. For this I built Gatekeeper, a tool that verifies BIP-322 message signatures. The flow is simple: the customer signs a known message with their hardware wallet at the relevant derivation path, and Gatekeeper confirms the signature matches the expected public key from the wallet descriptor. ...