Modified Advanced Encryption Standard using Butterfly Effect

Encryption is one of the key measures intends to guarantee the security of sensitive information. This paper used the Advanced Encryption Standard (AES) algorithm that used block ciphers. Each cipher is using several rounds with fixed operations in achieving the desired security level. The study presents a novelty on modifying the round function of the AES algorithm to increase the security of the encryption and decryption processes using Butterfly Effect. It utilizes the security level measurement namely the degree of diffusion, the degree of confusion and integrity check. Simulation of this study is done using PHP. There are ten (10) sets of data used in each security level for the consistency of results. Results showed that in the degree of diffusion, the original AES yields to 42.58% while the modified AES obtains 53.13% with an increase of 10.55%. In the degree of confusion, the former results to 46.64% while the latter gains 51.95% with an increase of 5.31%. In the integrity check, the former gets 46.02% while the latter advances to 53.67% with an increase of 7.65%. Thus, it is very evident that the test result for the Modified AES has a higher percentage than the original AES in providing better security in the ciphertext and improves the overall encryption and decryption processes.