Military Security Levels
DoD classifies information into 4 levels unclassified < confidential < secret < top secret
These classifications are applied to information in particular areas such as GUNS MIDDLEEAST etc.
Documents are labeled by secrecy level and area
Individuals and programs are given clearances such as (SECRET,{WEBTECH,HPCC})
A human can only run a process with a security rating equal or below that of human
A process can only read information marked with a security level equal to or below that of process
A process can only write information information with a security level equal to or above that of process.