Name:inspection of incoming and outgoing materials
All material is examined when crossing some boundaries to
assure that corruption or leakage is not taking place. Examples include
examination of incoming hardware for Trojan horses, bomb detection, and
detection of improperly cleansed material being sent out.
Complexity: Because information can be encoded in an unlimited number of
ways, it can be arbitrarily complex to determine whether inbound our out-bound
information is inappropriate. This is equivalent to the general computer
virus and Trojan horse detection problems.