Question-1 Write short note on Design Principles of Security.
Principles of Least Privileges:
- It restricts how privileges are granted.
- This principle states how the privileges are to be granted to a subject. A subject should be given only those privileges that it requires for completing a task.
- If a subject does not need a specific right it should not be granted that right.
- For example, if a subject requires append rights to an object then it must be given only the append rights and not the write rights.
Principe of Fail Safe Defaults:
- It restricts how privileges are initialized when a subject or object are created.
- This principle states that unless the subject is given explicit access to the object it should be denied access to that object.
- This means that the default access to object is none.
- All the access rights should be given explicitly granted.
Principle of Economy of Mechanisms:
- This principle simplifies the design and implementation of security mechanisms.
- This principle states that security mechanism should be as simple as possible.
- If design is simple there are fewer chances for errors.
- The checking and testing procedure becomes simpler.
Principles of Complete Mediation:
- This principle states that all the accesses to object be checked in order to ensure that they are allowed.
- Whenever a subject attempts to read an object the OS mediate the action.
- First it determines if the subject is allowed to access the object.
- If so it provides resources for reading the object.
- If the subject reattempts the read operation then it checks if the subject is still allowed to read the object and then allows for reading.
Principle of Open Design:
- This principle suggests that complexity doesn’t add security.
- This principle states that the security of mechanism should not depend on the secrecy of its design or implementation.
Principles of Separation of Privileges:
- This principle states that the access of an object should not depend only on fulfilling a single condition.
- There should be multiple conditions required to grant privilege and two or more system components work together to enforce security.
Principles of Least Common Mechanism
- This principle states that the amount of mechanism common to and depending on multiple users should be kept to the minimum possible.
Principles of user Acceptability
- This principle states that the mechanism used for protection should be acceptable to the users and should be easy to use.
- Otherwise, the user may feel a burden to follow the protection mechanism.