"Extraordinary" means outside the realm of ordinary. Signing a message is very ordinary
EDIT: Sorry I ment to say: saying "I own a key" is ordinary, and signing a message is the ordinary way to prove you own the key
"Extraordinary" means outside the realm of ordinary. Signing a message is very ordinary
EDIT: Sorry I ment to say: saying "I own a key" is ordinary, and signing a message is the ordinary way to prove you own the key