How can an app prove I own a Kaspa address?

An application can ask you to sign a short message with your private key, then verify the signature against your public key — proving ownership without ever seeing the private key itself. Your public key is your Kaspa address in disguise: it's safe to share, but only someone who holds the matching private key can produce a valid signature. The verification step uses Schnorr verify on a BLAKE2b hash of your message (with the domain tag 'PersonalMessageSigningHash'), returning true only if the signature genuinely came from the private key that corresponds to the public key being tested. This matters because it's the foundation of wallet-based login and in-app authentication on Kaspa — no password, no email, just cryptographic proof.