If that works, it works without bitcoin. I can send that messaged, signed, with or with out bitcoin. Conversely, no bitcoin script can force me to sign that mes

If that works, it works without bitcoin. I can send that messaged, signed, with or with out bitcoin. Conversely, no bitcoin script can force me to sign that message since no bitcoin script can contain that private key. Just because a systems uses public key crypto , doesn't mean its works with bitcoin. In the sense that it works securely. It clearly works for giving someone authorization.