In the physical security context, a security door equipped with an electronic lock configured to ignore the unlock
signals sent from the building emergency access control system in the event of an issue (fire, intrusion, power
failure) would be in which of the following configuration?

A.
Fail Soft

B.
Fail Open

C.
Fail Safe

D.
Fail Secure

Explanation:
Doorways with automatic locks can be configured to be fail-safe or fail-secure. A fail-safe setting means that if a
power disruption occurs that affects the automated locking system, the doors default to being unlocked. Failsafe deals directly with protecting people. If people work in an area and there is a fire or the power is lost, it is
not a good idea to lock them in.
A fail-secure configuration means that the doors default to being locked if there are any problems with the
power. If people do not need to use specific doors for escape during an emergency, then these doors can most
likely default to fail-secure settings.
Incorrect Answers:
A: Doorways with automatic locks can be configured to be fail-safe or fail-secure. “Fail-soft” is not a valid term
when talking about doorways with automatic locks. Therefore, this answer is incorrect.
B: A fail-safe setting means that if a power disruption occurs that affects the automated locking system, the
doors default to being unlocked. “Fail-open” is essentially the same as fail-safe although fail-safe is the more
commonly used terminology. In a fail-safe or fail-open system, the doors do not remain locked. Therefore, this
answer is incorrect.
C: A fail-safe setting means that if a power disruption occurs that affects the automated locking system, the
doors default to being unlocked; the doors do not remain locked. Therefore, this answer is incorrect.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, p. 451