Abstract

Information security depends on the strength of cryptographic algorithm and key. The generated keys must be so secure that there is no better way to break it. Design of such good key scheduling algorithm is crucial part in symmetric cryptosystem, which is used to create a number of subkeys, used in encryption/decryption process in block cipher. In this paper a methodology is proposed for generating keys using an alternate key scheduling algorithm of blowfish. However, Blowfish has some demerits including complex key scheduling algorithm, high computational cost and static substitution of S-box. Therefore such demerits are taken care to improve the performance of key generation algorithm of blowfish algorithm. This alternating key scheduling algorithm decreases the computational cost and uses the dynamic substitution of S-box. The effectiveness of the proposed scheme is verified by performing security analysis and also metrics evaluation.

References

• Jawad Ahmad and Fawad Ahmed. Efficiency analysis and security evaluation of image encryption schemes. International Journal of Video and Image Processing and Network Security IJVIPNS-IJENS, 12(4):8, 2007.
• D Whiting B. Schneier. Fast software encryption: Designing encryption algorithms for optimal software speed on the intel pentium processor. Lecter notes in Computer Science, 1997.
• B.Schneier. The blowfish encryption algorithm. In Dr Dobbs Journal, pages 38–40, 1994.
• Hamdy M. Kalash Hossam El din H. Ahmed and Osama S. Farag Allah. Encryption quality analysis of rc5 block cipher algorithm for digital images. Journal of Optical Engineering, 45, 2006.
• Dr. V Ramaswamy Krishnamurthy G N. Encryption quality analysis and security evaluation of blow-castfish using digital images. Communicated to International Journal of Computational Science, 2008.
• Yeong-Kang Lai and Yu-Chuan Shu. A novel vlsi architecture for a variable-length key, 64-bit blowfish block cipher. IEEE workshop on signal processing systems. SiPS 99. design and implementation, 1999. doi:10.1109/sips.
• K. Baskaran P. Karthigakumar. Partially pipelined vlsi implementation of blowfish encryption/decryption algorithm. International Journal of Image and Graphics, 10(3):327–341, 2010.
• K. Baskaran P. Karthigakumar. Partially pipelined vlsi implementation of blowfish encryption/decryption algorithm. International Journal of Image and Graphics, 10, 2010.
• B. Schneier. Description o f a new variable-length key,64-bit block cipher (blowfish). Fast Software Encryption,Cambridge Security Workshop proceedings (December 1993), December 4 1994. Springer-Verlag.
• B. Schneier. Applied cryptography: Protocols, algorithms, and source code in c. John Wiley and Sons, 1995.
• W. Stallings. Cryptography and Network Security: Principles and Practices. 2nd ed., Prentice Hall, 1999.
• Rahil Abbas; Vijayalakshmi S Sudarshan, TSB; Mir. Dril a flexible architecture for blowfish encryption using dynamic reconfiguration replication inner-loop pipelining loop folding techniques. Springer, page 625 639, 2005. Advances in Computer Systems Architecture.