This document discusses network security. It covers the need for security, goals of security like integrity, confidentiality, authentication, non-repudiation and availability. It then discusses famous malware types like viruses, worms and trojan horses. Viruses attach to programs and run when the program runs, worms replicate endlessly without causing harm, and trojan horses provide unauthorized access. The document also covers phishing scams and cryptography techniques like encryption, decryption, symmetric and asymmetric key cryptography.

1. NETWORK SECURITY
Ms. Mousmi Pawar

2. OVERVIEW
1. Need for Security
2. Goals of Security
3. Famous Malwares and Phishing
4. Cryptography

3. NEED FOR SECURITY

4. GOALS OF SECURITY
 Integrity
 Confendtiality
 Authentication
 Non-Repudiation
 Availability
 Access Control

5. INTEGRITY
 Protect the information INTEGRITY
This type of attack is called Modification
Transfer `1000
To
B
Ideal route of the message
Transfer `1000
To
C
Actual route of the message
A
X

6. CONFIDENTIALITY
 Guarantee Data Confidentiality
This type of Attack is called Interception.
To:aaa@gmail.com
ATM pin is 9876
X
A

7. AUTHENTICATION
Absence of proper authentication is called Fabrication.
A
I am user A
Transfer `5000 to
X
X

8. NON-REPUDIATION
Transfer `1000
To
B
I never
requested to
transfer `1000
to B
A
A

9. AVAILABILITY & ACCESS CONTROL
This type of attack is called Interruption.
username: aaa@gmail.com
Password: ********
-----
-----
-----
-----
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Read
Read, Write
Read

10. FAMOUS MALWARES
 Viruses
 Worms
 Trojan Horse

11. VIRUS
 A virus is a piece of program code that attaches itself to
legitimate program code and runs when the legitimate
program runs.
Sum=a+b;
Print sum;
End.
Sum=a+b;
Print sum;
Virus Code
End.
Original Code
Original Code
+ Virus code
Delete all files
Send copy of myself
to all using user’s
address book.
Virus code

12. WORM
 A worm does not modify the program, instead it
replicates itself again and again.
Resource
eating and
no
destruction
Resource eating
and no destruction
Resource eating
and no destruction
Resource eating
and no destruction
Resource
eating and no
destruction
Resource
eating and no
destruction
Resource eating
and no destruction

13. TROJAN HORSE
 It provides the attacker with unauthorized remote access to
a compromised computer, infects files and damages the
system, or steals user sensitive information.
username: aaa@gmail.com
Password: ********
Trojan Program
A
X

14. X

15. PHISHING
 Attacker set up fake website which looks like real
website to obtain your details.

16. CRYPTOGRAPHY
 Cryptography is the science of achieving security by
encoding messages to make them non-readable.
 Encryption: The process of encoding plain text message
into cipher text message is called as encryption.
 Decryption: the reverse process of transforming cipher
text to plain text is called decryption.

17. CRYPTOGRAPHY MECHANISM
 Every Encryption and Decryption process has 2 aspects:
the algorithm and the key used for encryption.
 Symmetric key Cryptography: If the same key is used for
encryption and decryption.(e.g. DES)
 Asymmetric key Cryptography/Public Key Cryptography: if
two different keys are used for encryption and decryption
process(e.g. RSA)

18. REFERENCES
 Cryptography and Network Security, Atul Kahate, Tata
McGraw Hill.
 http://en.wikipedia.org/wiki/Cryptography.- Wikipedia.

19. THANK YOU