How would you describe a simple yet very effective mechanism for sending and receiving unauthorized information…?

How would you describe a simple yet very effective mechanism for sending and receiving
unauthorized information or data between machines without alerting any firewalls and IDS’s on a
network?

A.
Covert Channel

B.
Crafted Channel

C.
Bounce Channel

D.
Deceptive Channel

Explanation:
A covert channel is described as: “any communication channel that can be exploited
by a process to transfer information in a manner that violates the systems security policy.”
Essentially,it is a method of communication that is not part of an actual computer system
design,but can be used to transfer information to users or system processes that normally would
not be allowed access to the information.