Commercial Flights Are Experiencing ‘Unthinkable’ GPS Attacks and Nobody Knows What to Do::New “spoofing” attacks resulting in total navigation failure have been occurring above the Middle East for months, which is “highly significant” for airline safety.
You can have a digital signature, so the recievers know it’s legit
yes of course, but that isn’t authentication.
Playing with semantics a little, it can be thought of as the satellite authenticating with the client using the signature as password.