Modifying Blowfish Algorithm Using Permutation Techniques

This paper proposes a modified version of the Blowfish Algorithm using permutation techniques. These techniques are key parts of the F-function of the algorithm. The first modification is in the bit operations while the second part employs the cyclical Shift Rows operation. We conducted simulations to test the security strength of the modified Blowfish Algorithm in changing one bit from two input strings. The avalanche effect showed 54.687% and 53.125% changes in the output bits thus making our model secure. We also tested the execution performance of the original Blowfish Algorithm and the modified Blowfish Algorithm in the encryption and decryption processes. While the original version performs better than the modified version, no statistical difference was found between the two versions.