Introduction to network security


Network security refers to any activities designed to protect the network.

Network security targets a variety of threats and stops them from entering or spreading on your network.

Network security consists of the policies and practices adopted to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources.

Key principles of security:

Confidentiality: Only sender, intendent receiver should understand message content,

  • Sender encrypts message.
  • Receiver decrypts message.

Authentication: Sender, receiver want to confirm identity of each other.

Message integrity: Sender receiver wants to ensure message not altered without detection. Data must be arrived at the receiver exactly as it was sent.

Accessibility & availability: Service must be accessible and available to users.

Non-Reduplication: Non reduplication means that a receiver must be able to prove that a receiver message came from a specific sender.

Privacy is achieved through encryption of plain text and decryption of the Cipher text.

Authentication, integrity and non-reduplication are achieved through a method called digital signature.

Access authorization is a security procedure in which the identity of a sender is verified prior to the sending of a message.

A network security system usually consists of many components. Ideally, all components work together, which minimizes maintenance and improves security.

Network security components often include :
  1. Anti-virus and anti-spyware.
  2. Firewall, to block unauthorized access to your network.
  3. Intrusion prevention systems (IPS), to identify fast-spreading threats.
  4. Virtual Private Networks (VPNs), to provide secure remote access.

More topics from NWS to read:
Python Programming ↓ 👆
Java Programming ↓ 👆
JAVA covered following topics in these notes.
JAVA Programs
Principles of Programming Languages ↓ 👆
Principles of Programming Languages covered following topics in these notes.

Previous years solved papers:
A list of Video lectures References:
  1. Sebesta,”Concept of programming Language”, Pearson Edu 
  2. Louden, “Programming Languages: Principles & Practices” , Cengage Learning 
  3. Tucker, “Programming Languages: Principles and paradigms “, Tata McGraw –Hill. 
  4. E Horowitz, "Programming Languages", 2nd Edition, Addison Wesley

    Computer Organization and Architecture ↓ 👆

    Computer Organization and Architecture covered following topics in these notes.

    1. Structure of desktop computers
    2. Logic gates
    3. Register organization
    4. Bus structure
    5. Addressing modes
    6. Register transfer language
    7. Direct mapping numericals
    8. Register in Assembly Language Programming
    9. Arrays in Assembly Language Programming


    1. William stalling ,“Computer Architecture and Organization” PHI
    2. Morris Mano , “Computer System Organization ”PHI

    Computer Network ↓ 👆
    Computer Network covered following topics in these notes.
    1. Data Link Layer
    2. Framing
    3. Byte count framing method
    4. Flag bytes with byte stuffing framing method
    5. Flag bits with bit stuffing framing method
    6. Physical layer coding violations framing method
    7. Error control in data link layer
    8. Stop and Wait scheme
    9. Sliding Window Protocol
    10. One bit sliding window protocol
    11. A protocol Using Go-Back-N
    12. Selective repeat protocol
    13. Application layer
    1. Andrew S. Tanenbaum, David J. Wetherall, “Computer Networks” Pearson Education.
    2. Douglas E Comer, “Internetworking with TCP/IP Principles, Protocols, And Architecture",Pearson Education
    3. KavehPahlavan, Prashant Krishnamurthy, “Networking Fundamentals”, Wiley Publication.
    4. Ying-Dar Lin, Ren-Hung Hwang, Fred Baker, “Computer Networks: An Open Source Approach”, McGraw Hill.