Logic of Security Models

Can I recap this whole thing? Let me try. So, we defined a model like model is a hypothetical abstraction of a system which is used to study some part of the system without going into too many details of the whole system. The modelling can be done formally and informally. The informal modelling can help in some subjective interpretation of the system whereas in formal modelling is mathematical and it is objective and it can help in programming the logic in the computer chips as well. So, this is the formal definition of security model. Now, in security models we discuss two things. We discuss finite state machine and lattice. Lattice is a set of security states with partial ordering where we define subjects and objects and we assign the security levels to that matrix which is kind of access matrix what a subject can do with what object. This relationship is expressed in that matrix. We will go in detail in the next video. Now, this relationship between the elements of a set which we define in the lattice is called the partially ordered set. The partially ordered set has got elements and there is the reflexive, anti-symmetric and transitive. So, if these things are maintained it means that the set is a partially ordered set and it is a part of lattice space security model. Now, before I jump into the next video I think I have not explained what is meant by reflexive, what is meant by anti-symmetric and what is meant by transitive.