Application of Linear Congruent Generator in Affine Cipher Algorithm to Produce Dynamic Encryption
Ofelius Laia, Elviawaty Muisa Zamzami, Sutarman Sutarman, Fati Gratianus Nafiri Larosa, Asaziduhu Gea · Journal of Physics Conference Series · 2019
Abstract Modification of the original message (plaintext) with the LCG random number generator algorithm and encryption with the affine cipher algorithm to produces a dynamic and safe random message (ciphertext) compared to just the affine cipher algorithm. The plaintext is converted to ASCII code and stored in a data list. The data list that contain the plaintext changes the position of the data where each plaintext column is moved to an odd column and even columns are filled by random numbers generated by LCG. The data list is then changed again by adding value to each column with random numbers generated by the programming language and then it encrypted with the affine cipher algorithm. The total number of ciphertexts can be twice as many as the plaintext. The results obtained are not the same ciphertext character even though the plaintext has the same character. Ciphertext generated in the first run program will be different for the next run program or dynamic encryption. To restore a ciphertext to the plaintext is done based on the affine cipher decryption function and the steps to modify the message that was done before.