Which type of access control applies the strictest access control and is commonly used in military or mission critical applications?mandatory access control (MAC)discretionary access control (DAC)Non-discretionary access controlattribute-based access control (ABAC)

To determine which type of access control applies the strictest access control and is commonly used in military or mission-critical applications, let's analyze each option step by step:

1. Mandatory Access Control (MAC):

   • Definition: MAC is a type of access control where the operating system or security policy enforces access controls based on predefined rules. Users do not have the ability to change access permissions.
   • Characteristics:
     • Access decisions are based on the classification of information and the clearance level of users.
     • It is highly structured and rigid.
     • Commonly used in environments where security is paramount, such as military and government applications.
   • Strictness: Very strict, as users cannot alter access permissions.

2. Discretionary Access Control (DAC):

   • Definition: DAC allows the owner of the resource to decide who can access it. The owner has the discretion to grant or revoke access permissions.
   • Characteristics:
     • Flexible and user-driven.
     • Access control is based on the identity of the users and their permissions.
   • Strictness: Less strict compared to MAC, as users have control over access permissions.

3. Non-discretionary Access Control:

   • Definition: This is a broad category that includes access control mechanisms where access decisions are not left to the discretion of the users. It includes models like Role-Based Access Control (RBAC).
   • Characteristics:
     • Access is based on roles or predefined policies.
     • More structured than DAC but can vary in strictness.
   • Strictness: Can be strict, but not necessarily as strict as MAC.

4. Attribute-Based Access Control (ABAC):

   • Definition: ABAC makes access decisions based on attributes (characteristics) of users, resources, and the environment.
   • Characteristics:
     • Highly flexible and dynamic.
     • Access policies can be complex and context-sensitive.
   • Strictness: Can be very strict, but its flexibility makes it less rigid than MAC.

Conclusion: The type of access control that applies the strictest access control and is commonly used in military or mission-critical applications is Mandatory Access Control (MAC). This is because MAC enforces access controls based on strict, predefined policies that users cannot alter, making it ideal for high-security environments.