CIP Proof Ownership for Stake Address

[jochen]

CIP7 message signing might come in handy here:

Message Signing specification

Private keys can be used to sign arbitrary data. If you have the public key, you can verify the data was signed by the owner of the private key. This is how transaction signing works internally but its utility is not limited to transactions. This document tries to set a standard for how to represent and verify signed messages for Cardano.

CIP7 - Message signing