Computer security involves protecting systems from threats like viruses, worms, Trojan horses, and hackers through mechanisms like cryptography, digital signatures, and firewalls. Key aspects of security include availability, integrity, and confidentiality of data and systems. Common malicious software include viruses that replicate and infect files/boot sectors, worms that spread through email/networks to perform destructive actions, and Trojan horses that are hidden in downloads to act like viruses or worms.

1. Computer Security
“An overriding concern”
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2. Introduction
2
Protection From

3. 3 Availability
Integrity
Confidentiality
Computer Security
Aspects

4. What are security threats?
Malicious
Code
Malicious
Programs
Hackers
Crackers
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5. Malicious Software
Virus
Worm
Trojan
Horse
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6. Virus
Programs designed to replicate
Usually have extensions like .exe, .com, .bat etc.
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7. Types of Virus
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• Affects master boot
record
• Infects rapidly
• Difficult to remove
Boot
Sector
• Infects .com & .exe
• Replicates itself
File
Infecting

8. Worms
Programs to perform destructive computer
processing
Use network connection to spread
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9. Worms
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Fake mails
Remote login
cracking

10. Trojan Horses
A destructive program
Usually present in downloadable files
Performs like virus and worms
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11. Stay Protected
“use protection medium”
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12. Security Mechanisms
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Cryptography
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Digital
Signature
2
Firewall
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13. Cryptography13
Simply hiding original information
from third party
Converts information to unreadable
format for hackers and crackers.

14. Cryptography techniques14
SKC
• Single Key
• En/de-cryption
PKC
• Two keys
• En/de-cryption
Hash
Functions
• No keys
• As password

15. Digital Signature15
Digitized form of paper signature
Verifying electronic documents

16. Firewall
Medium, software, system ,device.
Control over Networks
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17. Firewall
protects from
Unwanted
traffic
Vulnerable
system
Information
leak
Virus
Hackers
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18. What is security awareness?
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19. What is security policy?
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