Network Security Parameters

The security of the network can be gauged by considering the following parameters;

1. Authentication:

It is the verification that the communication parties are the ones that are claimed.

2. Access Control:

Access control includes the access provision to only intended parties to access the data or resources.

3. Integrity:

It includes the assurance that the data which was sent by the actual sender is received without any modification by any third party. In other words, the data is received by the receiver as it was originally sent by the sender.

4. Confidentiality:

It includes the assurance that the secrecy of the data is preserved. The data is not disclosed to the un-authorized users.

5. Non-repudiation:

Protection against the denial of the communication by any one of the parties.

Before We Get Started

What is Cryptology?

Cryptology is a study of techniques consisting of the techniques required for ensuring the authenticity and confidentiality of the information.
Cryptology has two main branches;
- Cryptography
                         Which literally means hidden writing. It's the study of the design of such techniques.

- Cryptanalysis
                         Which deals with the analysis of these techniques, to recover the information, which is authentic.

What is Network Security?

Network security is making use of cryptographic algorithms in network protocols and network applications in an order to ensure their security.

What is Computer Security?

Computer security is the security of computers against hackers and malicious software/viruses.

The OSI Security Architecture

The OSI(Open Systems Interconnection) security architecture provides a systematic framework for defining security attacks, mechanisms and services.

Security Attacks

Attacks to breach or threaten the security are known as security attacks.
There are two types of security attacks;
1. Active Attacks
     These attacks include modifying the information without authorization.
2. Passive Attacks
     These attacks include unauthorized monitoring of the information.

Security Mechanism

Any mechanism that is designed to detect, prevent, or recover from security attack. Example: authentication protocols, encryption algorithms, etc.

Security services

Security services include data confidentiality, access control, authentication, non-repudiation, data integrity, and availability.

Relations and Functions

1. Relation

Let A and B be two sets. A binary relation from A into B is any subset of the Cartesian product A x B.

Example: 

Let's assume that a person owns three shirts and two pairs of trousers.

So, let A = {yellow shirt, green shirt, red shirt} and

           B = {blue trouser, black trouser}

Then A x B = {(yellow shirt, blue trouser), (green shirt, blue trouser), (red shirt, blue trouser), (yellow shirt, black trouser), (green shirt, black trouser), (red shirt, black trouser)}

• Relation on a Set

A relation from a set A into itself is called a relation on A.

• Properties of Relations

Let's assume that R is a relation on set A; in other words, R ⊆ A x A. Let's write a R b to denote (a,b)∈ R.

1. Reflexive

R is reflexive if for every a ∈ A, aRb.

2. Symmetric

R is symmetric if for every a and b in A, if aRb, then bRa.

3. Transitive

R is transitive if for every a, b and c in A, if aRb and bRc, then aRc.

4. Equivalence

R is equivalence relation on A if R is reflexive, symmetric and transitive.

2. Function

A function, denoted by f, from a set A to a set B is a relation from A to B that satisfies;

- for each element a in A, there is an element b in B such that <a,b> is in a relation, and

- if <a,b> and <a,c> are in the relation, then b=c.

The set A in the above definition is called the domain of the function and B is its co-domain.