2. SECURITY
SECURITY THREATS
SECURITY GOALS
WHAT IS CRYPTOGRAPHY
BASIC TERMS
ENCRYPTION & DECRYPTION
CATEGORIES OF CRYPTOGRAPHY
COMPARISON
CONCLUSION

3. SECURITY???
Network security is an over arching term.

4. 1. Passive threats
2. Active threats

7.  PLAIN TEXT
 CIPHER TEXT
 CIPHER
 ENCRIPTION & DECRYPTION
 KEYS

9. A. Symmetric cryptography
B. Asymmetric cryptography

10. SYMMETRIC KEY CRYPTOGRAPHY
o also known as secret key cryptography.
o Sender & receiver uses same key for
encryption & decryption namely public key

12. a. Traditional cipher
b. Modern cipher
Two types traditional cipher
i. Substitution cipher
ii. Transposition cipher

13. A substitutional cipher is one in which the
letters/numbers/symbols is replaced by other
letters/numbers/symbols
e.g
A d, t z
2 5, 3 6

15.  Also known as public key
 Sender and receiver uses
 different keys for encryption and
 decryption namely public & private key

18. COMPARISON
Symmetric key cryptography Asymmetric key cryptography
1. The same algorithm with
same key is used for
encryption & decryption
2. The key must be kept
secret
3. may be impossible or at
least impractical to
decipher a message if no
other information is given
1. One algorithm is used for
encryption & other for
decryption with a pair of
keys respectively
2. One of the key must be
kept secret
3. It may be impossible or at
least impractical to
decipher a message if no
other information is given

19. • Defense services
• Secure data manipulation
• Business transactions
• Internet payment systems
• User identification systems
• Acess control
• Data security

20.  By using of encryption techniques ,a fair unit of
confidentiality,authentication,integrity,acess control and
availability of data is maintained

21. thanks