Introduction to Network Security

INTRODUCTION TO
NETWORK SECURITY

What is a Network?
 A network consists of two or more computers that are linked in order to share resources
exchange files, or allow electronic communications.
 The computers on a network may be linked through cables, telephone lines, radio waves,
satellites, or infrared light beams.
 The Three Types of Area Networks are:
1. LAN (Local Area Network)
2. MAN (Metropolitan Area Network)
3. WAN (Wide Area Network)

What is a Network Security?
 Network security is any activity designed to protect the usability and integrity of our
network and data.
 It includes both hardware and software technologies.
 It targets a variety of viruses and threats.
 It stops them from entering or spreading on our network.
 Effective network security manages access to the network.

Fundamentals of Network Security:
Network Security refers to three core elements, known as the CIA Triad:
1. Confidentiality (C)
2. Integrity (I)
3. Availability (A)

Types of Network Security:
 Firewall
 Network Segmentation
 Remote Access VPN
 Email Security
 Data Loss Prevention
 Intrusion Prevention System
 Cloud Network Security
 Anti-Virus

Network Security Attack?
Definition:
A network attack can be defined as any method, process, or means used to
maliciously attempt to compromise network security.
Classification of Network Security Attacks:
1. Active Attacks
2. Passive Attacks

Active
Attacks:
 Active Attacks are the attacks in which the attacker tries to modify the information
or creates a false message.
 The prevention of these attacks is quite difficult because of a broad range of
potential physical, network and software vulnerabilities.

Types of Active Attacks:
 Masquerade Attack (Interruption)
 Modification of messages
 Repudiation
 Replay
 Denial of Service (DoS)

Passive
Attacks:
 Passive attacks are the attacks where the attacker indulges in unauthorized
eavesdropping, just monitoring the transmission or gathering information. The
eavesdropper does not make any changes to the data or the system.

Types of Passive
Attacks:
 Traffic Analysis
 Eavesdropping
 Footprinting
 Spying
 War driving

Threats & Vulnerabilities:
 Virus
 Worms
 Trojan (or Trojan horse)
 Spyware
 Adware
 Ransomware
 Malware (or Malicious Software)

Cryptography:
 In Cryptography, the prefix “Crypt” means “hidden” and suffix “graphy” means
“writing”.
 It is a technique of securing information & communications through use of codes
so that only authorized person can understand the information and process it.
Thus, preventing unauthorized access to information.

Cryptography: (Cont.)
 This basic principle is used to protect information obtained from mathematical
concepts and algorithms to convert messages which are hard to decode it.
 These algorithms are used for cryptographic key generation, digital signing,
verification to protect data privacy, web browsing on internet and to protect
confidential transactions such as credit card and debit card transactions.

Block Diagram of Cryptography:
Block Diagram of Cryptography

Features of
Cryptography:
 Confidentiality: Information can only be accessed by the person for whom it is
intended and no other person except him can access it.
 Integrity: Information cannot be modified in storage or transition between
sender and intended receiver without any addition to information being
detected.
 Non-Repudiation: The creator/sender of information cannot deny his or her
intention to send information at later stage.
 Authentication: The identities of sender and receiver are confirmed. As well as
destination/origin of information is confirmed.

Types of Cryptography:
 In General, there are 3 types of Cryptography:
1. Symmetric Key Cryptography
2. Asymmetric Key Cryptography
3. Hash Functions

1. Symmetric Key Cryptography:
 An encryption system where the sender and receiver of message use a single
common key to encrypt and decrypt messages.
 Symmetric Key Systems are faster and simpler.
 The most popular symmetric key cryptography system is Data Encryption
System (DES).

2. Asymmetric Key Cryptography:
 In this system, a pair of keys is used to encrypt and decrypt information.
 A Public key is used for encryption and a Private key is used for decryption.
Public key and Private Key are different. Even if the public key is known by
everyone, the intended receiver can only decode it because he alone knows the
private key.

3. Hash Functions:
 No usage of any key in this algorithm. A hash value with fixed length is
calculated as per the plain text which makes it impossible for contents of plain
text to be recovered. Many OS use hash functions to encrypt passwords.

Advantages of Cryptography:
1. Confidentiality: Encryption technique can guard the information &
communication from unauthorized revelation and access of information.
2. Authentication: The cryptographic techniques such as MAC and digital
signatures can protect information against spoofing and forgeries.
3. Data Integrity: The cryptographic hash functions plays a vital role in assuring
the users about the data integrity.
4. Non-repudiation: The digital signature provides the non-repudiation service to
guard against the dispute that may arise due to denial of passing message by
the sender.

Disadvantages of Cryptography:
 A strongly encrypted, authentic, and digitally signed information can be difficult
to access even for a legitimate user at a crucial time of decision-making.
 High availability cannot be ensured through the use of cryptography.
 Information security of selective access control cannot be realized through the
use of cryptography.
 Cryptography does not guard against the vulnerabilities and threats that emerge
from the poor design of systems, protocols, and procedures.

Introduction to Network Security

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Introduction to Network Security