This document discusses cryptography and how it provides security. It defines basic cryptography terms like plain text, cipher text, encryption, and decryption. It explains how cryptography works to secure communications from both passive and active security threats. The document also categorizes different types of cryptography like symmetric and asymmetric key cryptography, and compares how each uses keys to encrypt and decrypt messages. Applications of cryptography are listed as well.

1. CRYPTOGRAPHY
BY ARYAN KUMAR
B.TECH CSE

2. CONTENTS
• SECURITY
• SECURITY THREATS
• SECURITY GOALS
• WHAT IS CRYPTOGRAPHY
• BASIC TERMS
• ENCRYPTION AND DECRYPTION
• CATEGORIES OF CRYPTOGRAPHY
• COMPARISION
• CONCLUSION

3. WHAT DOES SECURE MEANS ?

4. THREATS
PASSIVE
THREATS
ACTIVE
THREATS
RELEASE OF
MESSAGE
CONTENTS
TRAFFIC
ANALYSIS
MASQUERAD
E
REPLAY
MODIFICATIO
N OF
MESSAGE
CONTENT
DENIEL OF
SERVICE

5. SECURITY GOALS
INTEGRI
TY
NON-
REPUDATION
SECUR
E

6. CRYPTOGRAPHY
IT IS THE SCIENCE AND THE ART
OF TRANSFORMING MESSAGES
TO MAKE THEM SECURE AND
IMMUNE TO ATTACK.

7. BASIC TERMS
• PLAIN TEXT
• CIPHER TEXT
• ENCRYPTION
• DECRYPTION
• KEYS

8. ENCRYPTION AND DECRYPTION

9. CATEGORIES OF
CRYPTOGRAPHY

10. COMPARISION
SYMMETRIC KEY
CRYPTOGRAPHY
• The same algorithm with the same
key is used for the encryption and
decryption.
• The key must be kept secret.
• It may be impossible or at least
impractical to decipher a message if
no other information is available.
ASYMMETRIC KEY
CRYPTOGRAPHY
• One algorithm is used for
encryption and decryption with the
pair of keys one for encryption and
one for decryption.
• One of the two key must be kept
secret.
• It may be impossible or at least
impractical to decipher a message if
no other information is available.

11. APPLICATIONS
• Defense service
• E – commerce
• Business transactions
• Internet payment system
• User identification system
• Access control
• Data Security

12. CONCLUSION
•By using of CRYPTOGRAPHY technique a
fair unit of confidentiality ,authentication
,integrity access control and availability of
data is maintained.

13. THANK YOU