Design Principles of Security

Lists of Questions Answers and Short Study Notes On OS Security

  • (1) Write short note on Design Principles of Security.


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.