Orange Book

security, standard A standard from the US Government

National Computer Security Council (an arm of the

U.S. National Security Agency), "Trusted Computer System

Evaluation Criteria, DOD standard 5200.28-STD, December 1985"

which defines criteria for trusted computer products. There

are four levels, A, B, C, and D. Each level adds more

features and requirements.

D is a non-secure system.

C1 requires user log-on, but allows group ID.

C2 requires individual log-on with password and an audit

mechanism. (Most Unix implementations are roughly C1, and

can be upgraded to about C2 without excessive pain).

Levels B and A provide mandatory control. Access is based on

standard Department of Defense clearances.

B1 requires DOD clearance levels.

B2 guarantees the path between the user and the security

system and provides assurances that the system can be tested

and clearances cannot be downgraded.

B3 requires that the system is characterised by a mathematical

model that must be viable.

A1 requires a system characterized by a mathematical model

that can be proven.

See also crayola books, book titles.

[Jargon File]

(1997-01-09)