1. Data Encryption Standard -
DES
DES was developed as a standard for communications and data
protection by an IBM research team, in response to a public
request for proposals by the NBS - the National Bureau of
Standards (which is now known as NIST).
By:
T.N.Srimanyu (12MCMB06)
Ritika Singla (12MCMB15)
M.Tech(IT)

3. DES - Basics

DES uses the two basic techniques of cryptography -
confusion and diffusion.

At the simplest level, diffusion is achieved through
numerous permutations and confusion is achieved
through the XOR operation.

5. DES - The 16 Rounds

The basic process in
enciphering a 64-bit data block
and a 56-bit key using the
DES consists of:
• An initial permutation (IP)
• 16 rounds of a complex key
dependent calculation f
• A final permutation, being the
inverse of IP

8. Triple DES - More Secure

9. IMPROVED DES ALGORITHM
BASED ON IRRATIONAL
NUMBERS
IEEE Int. Conference Neural Networks & Signal
Processing
Zhenjiang, China, June 8~10, 2008

10. Irrational Numbers
 Irrational numbers, which are similar to data
sequences generated form chaotic system, are infinite and
non-cyclic.
Therefore using irrational numbers to encrypt will provide
higher security without strict chaos synchronization.

11. Advantages
 The improved scheme prevents the key from being
directly involved in the production of sub-keys.
It can increase the randomness of the production of the
sub-keys and use different sub-keys each group.
The key space is extended.

14. Conclusion
This paper designs an encryption algorithm with better
security, bigger secret-key space and higher encrypting
efficiency.
This scheme can expand the key space without any more
running time and enhance the security of the encryption
algorithm.
The algorithm has wider foreground applications based
on these advantages.

15. Bibliography
www.ieeexplore.com

16. Thank You
Any Queries?