Even if you use practically unbreakable encryption keys, there are a million things that you can fail in the whole cryptosystem and any one of them will make you vulnerable.
How are keys generated? What is the source of randomness? How are keys reset if needed? What are the manufacturer/service/guvmint backdoors in the keys? etc.
I think you're on to something with the backdoor.
Backdoors have to be extra secure because if you hack that you have access to all of them.
Hell they shouldn't even exist it's like asking to be exploited.
How are keys generated? What is the source of randomness? How are keys reset if needed? What are the manufacturer/service/guvmint backdoors in the keys? etc.