The Security Kernel

D.

The reference monitor, not the security kernel is an access control concept.

The security kernel is made up of software, and firmware components that fall within the TCB and implements and enforces the reference monitor concept.

The security kernel mediates all access and functions between subjects and objects.

The security kernel is the core of the TCB and is the most commonly used approach to building trusted computing systems.

There are three main requirements of the security kernel:It must provide isolation for the processes carrying out the reference monitor concept, and the processes must be tamperproof.It must be invoked for every access attempt and must be impossible to circumvent.

Thus, the security kernel must be implemented in a complete and foolproof way.It must be small enough to be able to be tested and verified in a complete and comprehensive manner.

The following answers are incorrect: The security kernel is made up of mechanisms that fall under the TCB and implements and enforces the reference monitor concept.

Is incorrect because this is the definition of the security kernel.

The security kernel must provide isolation for the processes carrying out the reference monitor concept and they must be tamperproof.

Is incorrect because this is one of the three requirements that make up the security kernel.

The security kernel must be small enough to be able to be tested and verified in a complete and comprehensive manner.

Is incorrect because this is one of the three requirements that make up the security kernel.

The security kernel is a fundamental concept in computer security that plays a crucial role in enforcing the security policy of a system. It is a collection of mechanisms that are implemented within the Trusted Computing Base (TCB) of a system and is responsible for enforcing the reference monitor concept. The reference monitor concept is a security mechanism that ensures that all accesses to system resources are authorized, auditable, and verifiable.

Option A is correct. The security kernel is made up of mechanisms that fall under the TCB and implements and enforces the reference monitor concept. The reference monitor concept is implemented using a set of security mechanisms that provide a means of enforcing the security policy of the system. These mechanisms include access control mechanisms, authentication mechanisms, and audit mechanisms.

Option B is also correct. The processes carrying out the reference monitor concept must be isolated and tamperproof. This means that the processes must be protected from unauthorized access, modification, or destruction. The security kernel is responsible for providing this protection by implementing security mechanisms such as process isolation, memory protection, and hardware security features.

Option C is also correct. The security kernel must be small enough to be tested and verified in a complete and comprehensive manner. This means that the security kernel must be designed in a way that makes it easy to test and verify that it is functioning correctly. The smaller the security kernel, the easier it is to test and verify.

Option D is incorrect. The security kernel is not just an access control concept, but it is also an actual physical component of a system. It is implemented as a set of software and hardware mechanisms that are responsible for enforcing the security policy of the system. The security kernel is typically implemented within the operating system kernel or as a separate trusted component within the hardware of the system.

In summary, option D is the incorrect statement pertaining to the security kernel. The security kernel is not just an access control concept, but it is also an actual physical component of a system that implements and enforces the reference monitor concept. The security kernel must be small enough to be tested and verified in a complete and comprehensive manner, and it must provide isolation and tamperproof protection for the processes carrying out the reference monitor concept.