DES was developed as a standard for communications and data protection by an IBM research team in response to a request from the National Bureau of Standards (now called NIST). DES uses the techniques of confusion and diffusion achieved through numerous permutations and the XOR operation. The basic DES process encrypts a 64-bit block using a 56-bit key over 16 complex rounds consisting of permutations and key-dependent calculations. Triple DES was developed as a more secure version of DES.

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?