1. PRESENTED BY:
1.BISWAJIT DATTA (09123002030)
2.AVIRUP SAMANTA (09123002071)
3.ANAND MOHAN MASKARA (09123002057)
COMPARATIVE STUDY OF
SYMMETRIC KEY
CRYPTOGRAPHY AND NEW
TECHNIQUE IMPLEMENTATION

2. INTRODUCTION
What is Cryptography?
Goal of Cryptography

3. HISTORY
The first use of cryptography in 1900 B.C.

4. PURPOSE OF CRYPTOGRAPHY
 Confidentiality
Authentication
 Integrity
 Non Repudiation
 Access Control

5. ENCRYPTION DECRYPTION
PLAIN
TEXT
PLAIN
TEXT
SENDER
CIPHE
RTEXT RECEIVER
BASIC BLOCK DIAGRAM

6. BASIC TERMINOLOGIES
Encryption
Decryption
Cryptosystem

7. TECHNIQUES OF CRYPTOGRAPHY
Substitution Technique
Transposition Technique

8. ENCRYPTION ALGORITHM
 Symmetric
 Asymmetric

9. SYMMETRIC ALGORITHM
Encryption Decryption
Key
Plaintext Cipher text
Original
Plaintext
Symmetric Cryptosystem
Data Encryption Standard (DES)
Advance Encryption Standard (AES)

10. ASYMMETRIC ALGORITHM
Rivest Shamir Adleman (RSA) Encryption
 Knapsack Algorithm
plaintext
encryption
public key
cipher text
decryption
private key
cipher text plaintext

11. SIMPLE ENCRYPTION SCHEME
(CAESAR’S CIPHER)
Substitution cipher:
Plain text: a b c d e f g h I j k l m n o p q r s t u v w x y z
Cipher text: m n b v c x z a s d f g h j k l p o I u y t r e w q
Example:
Plain text: HELLO WORLD
Cipher text: KHOOR ZRUOG

12. SIMPLE ENCRYPTION SCHEME
(RAIL FENCE TECHNIQUE)
H L O W R D
E L O L
 The Rail Fence Technique is an example of
Transposition Technique.
For example:
HELLO WORLDPlain text:
Cipher text: HLOWRDEL OL

13. SIMPLE ENCRYPTION SCHEME
(VERNAM CIPHER TECHNIQUE)
Vernam cipher uses a one time pad.
Example:
Plain text: HELLO WORLD
Cipher text: YW}}~F~C}U
Padding: SHARM QZNKP

14. DES (DATA ENCRYPTION STANDARD)
Example:
Plain text: HELLO WORLD
Cipher text: m0dh19VD0DXSrvJOhMOaEg==
DES was designed by IBM in
the 1970s and adopted by the
National Bureau of Standards
(NBS)

15. AES (ADVANCED ENCRYPTION STANDARD)
Example:
Plain text: HELLO WORLD
Cipher text: TpXlULf/l9GQX30osRMxTQ==
 128 Bit blocks
128 bit keys

16. MODIFIED ENCRYPTION TECHNIQUE
Modified encryption technique involves splitting up a
text into two parts, and then applying different
symmetric key cryptographic technique on them.
PLAIN TEXT : HELLO WORLD
PART 1 PART 2
HELLO WORLD
For example:

17. MODIFIED ENCRYPTION TECHNIQUE
APPLYING DIFFERENT TECHNIQUES ON TWO PARTS
PART 1 : HELLO
ENCRYPTED WITH CAESAR CIPHER: iffmp
PART 2: WORLD
ENCRYPTED WITH RAIL FENCE: olwrd
ENCRYPTED TEXT: iffmp olwrd

18. MODIFIED ENCRYPTION TECHNIQUE
Example: Hello World

19. Example: Hello World
MODIFIED ENCRYPTION TECHNIQUE

20. MODIFIED ENCRYPTION TECHNIQUE
Example: Hello World

21. Example: Hello World
MODIFIED ENCRYPTION TECHNIQUE

22. MODIFIED ENCRYPTION TECHNIQUE

23. MODIFIED ENCRYPTION TECHNIQUE
Advantage
Disadvantage

24. FUTURE SCOPE
 In future this technique can be modified by
implementing more encryption techniques of
cryptography to make the data more secure.
 The key can be conjugated as a single key.

25. CONCLUSION
Once the method has withstood all attacks for
sufficient length of time it may be used with a
reasonable amount of confidence.

26. THANK YOU