Write short note on Design Principles of Security.

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.