Final answer:
Covert channels in computer systems are unauthorized communication methods that can be storage or timing channels. These channels breach security by either manipulating data storage or observing the timing of system operations. The term leakage channel is more commonly associated with biology and ion channels than with computer security.
Step-by-step explanation:
Covert channels are unauthorized or unintended methods of communications hidden inside a computer system, often used to breach security controls. They can be classified into two main categories: storage channels and timing channels. Storage channels involve the transmission of information through a storage medium, such as a hard drive or memory, by manipulating the stored data or its attributes. Timing channels, on the other hand, communicate information by observing the timing of events or operations within the system. An example of a timing channel could be inferring the type of operations being performed by a CPU by observing the system's responsiveness.
While the term leakage channel is often used in the context of ion channels that open randomly and are not gated to a specific event, also known as a non-gated channel, in this context, it would not be accurate. In computer security, we are typically concerned with preventing the unauthorized transmission of information through covert channels.