Unit 1 — Principles of Cryptography & Cyber Security
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Foundations of Cyber Security Concepts
Cyber Security means protecting:
Computers
Networks
Software
Data
Digital systems
from:
Unauthorized access
Attacks
Damage
Theft
Malware
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Why Cyber Security is Important
Today everything is online:
Banking
Shopping
Government services
Education
Social media
If security is weak:
Data can be stolen
Money can be lost
Systems may stop working
Privacy gets compromised
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Essential Terminologies
1. CIA Triad
CIA is the foundation of Cyber Security.
(A) Confidentiality
Data should only be accessible to authorized people.
Example:
ATM PIN
Passwords
Bank details
Methods:
Encryption
Passwords
Authentication
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(B) Integrity
Data should not be modified illegally.
Example: Marks stored in university database should remain correct.
Methods:
Hashing
Digital signatures
Access control
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(C) Availability
Systems and data should be available whenever needed.
Example: Bank servers should work 24×7.
Methods:
Backups
Firewalls
Disaster recovery
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Risks
A risk is the possibility of damage or loss.
Example: Weak password can create risk of hacking.
Formula: Risk = Threat × Vulnerability
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Threats
Anything that can cause harm to a system.
Examples:
Hackers
Viruses
Natural disasters
Insider attacks
Types:
Internal threats
External threats
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Breach
Unauthorized access to confidential data.
Example: A hacker steals customer credit card information.
Data breaches may cause:
Financial loss
Reputation damage
Legal problems
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Attacks
An attempt to exploit vulnerabilities.
Types:
Phishing
Malware attack
SQL Injection
Denial of Service (DoS)
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Exploits
Code or techniques used to take advantage of vulnerabilities.
Example: Using a software bug to gain admin access.
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Information Gathering
The first step of hacking.
Attackers collect information about target systems.
Two main methods:
1. Social Engineering
2. Footprinting & Scanning
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Social Engineering
Manipulating people to reveal confidential information.
Example: Fake call asking for OTP or password.
Types:
Phishing
Vishing (voice call fraud)
Smishing (SMS fraud)
Prevention:
User awareness
Verification methods
Security training
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Footprinting
Collecting information about a target.
Information collected:
IP address
Domain details
Employee details
Network information
Methods:
WHOIS lookup
Google hacking
DNS queries
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Scanning
Used to identify:
Open ports
Services
Vulnerabilities
Types:
Port scanning
Network scanning
Vulnerability scanning
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Open Source / Free Tools
Nmap
Popular network scanning tool.
Features:
Detect hosts
Open ports
Services running
OS detection
Example command:
nmap 192.168.1.1
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Zenmap
GUI version of Nmap.
Advantages:
Easy interface
Visual scanning
Network mapping
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Port Scanner
Checks which ports are open.
Common ports:
80 → HTTP
443 → HTTPS
21 → FTP
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Network Scanner
Scans entire networks to identify:
Devices
IP addresses
Active systems
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Cyber Security Vulnerabilities
Weaknesses in systems.
Types:
1. Software Vulnerabilities
Errors or bugs in software.
Example: Outdated Windows OS.
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2. Weak Authentication
Weak passwords or no multi-factor authentication.
Example: Password = 123456
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3. Poor Authorization
Users getting access they should not have.
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4. Complex Networks
Large networks become difficult to manage securely.
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5. Open Access to Data
Sensitive data available publicly.
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6. Unprotected Communication
Data sent without encryption.
Example: Using HTTP instead of HTTPS.
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Cyber Security Safeguards
Methods used to protect systems.
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Access Control
Restricts who can access resources.
Types:
Role-based access
Password protection
Biometric authentication
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IT Audit
Checking security policies and systems regularly.
Purpose:
Find vulnerabilities
Ensure compliance
Improve security
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Authentication
Verifying identity of users.
Methods:
Passwords
OTP
Biometrics
Smart cards
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Important Exam Questions
Short Questions
1. Define Cyber Security.
2. Explain CIA Triad.
3. What is Footprinting?
4. Difference between Threat and Risk.
5. What is Social Engineering?
6. Define Vulnerability.
7. What is Authentication?
8. Explain Nmap.
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Long Questions (6–10 Marks)
1. Explain CIA Triad with examples.
2. Describe various Cyber Security vulnerabilities.
3. Explain Information Gathering techniques.
4. Discuss Social Engineering attacks and prevention.
5. Explain different Cyber Security safeguards.
6. Write detailed notes on Nmap and Zenmap.
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Quick Revision Notes
CIA = Confidentiality + Integrity + Availability
Threat = Possible danger
Risk = Chance of loss
Vulnerability = Weakness
Exploit = Method to attack weakness
Nmap = Network scanner
Footprinting = Information collection
Scanning = Finding open services
Authentication = Identity verification
Next topics in Unit 1:
Access Control
IT Audit
Authentication methods
Advanced scanning concepts
Practical cybersecurity tools
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