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Professiona Univ Unit 14: Network Security

Unit 14: Network Security Notes

CONTENTS
Objectives
Introduction

14.1 Network Security
14.1.1 Levels of Security
14.2 Data Security
14.3 Security Threats
14.4 Data Encryption
14.4.1 Translation
14.4.2 Encryption/Decryption

14.4.3 Authentication
14.4.4 Data Compression
14.5 Cryptography
14.5.1 Substitution Ciphers
14.5.2 Transposition Cipher
14.5.3 Substitution and Transposition Ciphers in Modern Times
14.6 Summary
14.7 Keywords
14.8 Review Questions

14.9 Further Readings

Objectives

After studying this unit, you will be able to:
Explain various aspects of network security for TCP/IP network

Discuss the possible issues for data security and how the same can be protected
Analyze the importance of data encryption and related technologies
Describe the concept of cryptography and its use in data security

Introduction

Over the past several years, the world has become interconnected in ways not previously
imaginable. Small and large companies have presence on WWW and their offices spread across
the globes have inter-office collaboration on a daily basis. Hence, all of these interconnections
rely in large part on our ability to protect the networks that create those connections. Network
security is a broad topic with multi-layered approach. It can be addressed at the data link layer,
network layer and application layer. The issues concerned are: packet intrusion and encryption,
IP packets and routing tables with their update version, and host-level bugs occurred at data link
layer, network layer and application respectively.

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