Penggunaan Fungsi Rasional, Logaritma Kuadrat, dan Polinomial Orde-5 dalam Modifikasi Kriptografi Caesar Cipher

Abstract

Caesar cipher is a substitution cryptography in which each letter of plain text will be replaced with a new letter in cipher text. Because there is a linear relationship between the plain text and the cipher text, which is the modulus 26, cryptanalysis and brute force attack can break this cryptography easily. This research discusses the modification of Caesar Cipher using rational functions, logarithmic equation and fifth order polynomial as the key. Cryptography process is designed to produce five rounds of plaintext and ciphertext. As a result, the modification can withstand cryptanalysis and brute force attack.