—In this paper, we have extended the analysis of the modified Playfair cipher, which includes interweaving and iteration, by considering a plaintext of any size. Here, we have carried out cryptanalysis and examined the avalanche effect. From this analysis, we have found that the cipher is a strong one and it cannot be broken by any cryptanalytic attack.
—interweaving, inverse interweaving, substitution matrix.
V. Umakanta Sastry is with the Department of Computer Science and Engineering, Sreenidhi Institute of Science and Technology, India. Phone:919985012707, fax:914027640394, e-mail: firstname.lastname@example.org.
N. Ravi Shankar is with the Department of Computer Science and Engineering, Sreenidhi Institute of Science and Technology, Hyderabad, India.
S. Durga Bhavani is with the School of Information Technology, J.N.T. University, Hyderabad, India.
Cite: V. Umakanta Sastry, N. Ravi Shankar, and S. Durga Bhavani, "A Modified Playfair Cipher for a Large Block of Plaintext," International Journal of Computer Theory and Engineering
vol. 1, no. 5, pp. 592-596, 2009.