Hybrid Cryptosystem Menggunakan Rivest Code 4 (RC4) dan H-Rabin pada Pengamanan Gambar

Abstract

The use of one cryptographic algorithm is still very vulnerable to security so a combination of two cryptographic algorithms is needed to produce a ciphertext that is difficult for unauthorized parties to understand in the process of sending messages. In addition, technological advances make it easy to exchange information by only being transmitted via the internet, causing many threats to the message, such as the threat of modification, forgery, and misuse of the information. Hybrid Cryptosystem is one of the combinations of symmetry and asymmetry algorithms by utilizing the advantages of data processing speed by symmetric algorithms and ease of key transfer using asymmetric algorithms. The Rivest Code 4 algorithm is one of the symmetric key algorithms, where the encryption and decryption process with the same key has a stream cipher working mode. The H-Rabin algorithm is a form of asymmetric encryption that utilizes random prime numbers to generate public keys. The file used is a .png format image file. The encryption process with the RC4 algorithm is successful in securing image files, so that the encrypted image file or the resulting ciphertext cannot be read. While the key encryption process with the H-Rabin algorithm successfully produces a cipherkey so that the original key is not known by other parties. Based on the results acquired, it can be concluded that carrying out the cryptographic process using the Hybrid Cryptosystem method which combines the Rivest Code 4 algorithm and the H-Rabin algorithm succeeds in restoring the integrity of the message as before and maintaining the security of image files from unauthorized parties.