Your initial assumption seems to be wrong. In cryptography there is one information theoretical secure scheme: The one time pad. But even that relies on circum

Your initial assumption seems to be wrong. In cryptography there is one information theoretical secure scheme: The one time pad. But even that relies on circumstances to keep it secure. Without limitations you can not say no one can break it, because obtaining the key material might still be possible. That leaves us with most other schemes. They are computationally secure. This implies that the security of the system depends on the computational power of the attacker. So a system can only be secure for a class of attackers and to a certain extent. If you apply a binary clssification of secure insecure as you proposed it someone can get in", most systems today, if not all, are insecure.