Cyberspace is an Information and Communications space.
In cyberspace information cannot be destroyed; only a copy of information can be destroyed.
Physical space is limited; cyberspace is unlimited.
Physical space has three dimensions; Cyberspace has unlimited dimensions.
In physical space visibility is unavoidable; in cyberspace visibility is optional.
In physical space only one identity is permitted; cyberspace permits multiple identities.
We developed our cyber defenses, largely based on variations
of a physical firewall. It does not work, and never did; it has been
mathematically proven that any firewall can be penetrated.
Cyberspace is fundamentally different from physical space.