AES-RC4 Encryption Technique to Improve File Security

In communicating in public networks, data security becomes very important. There are many risks of data theft by other parties. Cryptography is one technique for securing data. In cryptography, there are two main processes, namely encryption, and decryption. Encryption is the process of encoding the original or plaintext file into an encrypted or ciphertext file. While decryption is the process of returning encrypted data or ciphertext into original or plaintext data. There are various encryption algorithms nowadays, where the more complex encryption logically encryption will be stronger and harder to solve. This study proposed a combination of the AES and RC4 algorithms to provide protection against confidential data. The combination of this method aims to make the algorithm more complex and strong. To find out how safe an algorithm is, test the avalanche effect (AE). AE measurement is done by changing the value of one bit in the key, then the two results are ciphertext compared to the difference. The greater the difference, the better the encryption results. The ideal AE is around 50% and the greater the AE value means the better the quality of data encryption. Based on the combination test of the AES-RC4 method, the best AE results are 58.2%, where this value is far better than the AES algorithm, RC4 only or RC4-AES.