Enhancing the Hill Cipher Algorithm and Employing a One Time Pad Key Generation Technique

Abstract

Mobile money has evolved to enhance financial inclusion in many developing countries through the development of smartphones and financial technologies. The majority of mobile money schemes used in these nations implement two-factor authentication. However, these 2FA schemes are vulnerable to cryptanalysis and brute force attacks over time. This is because they only rely on a personal identification number and subscriber identity module. This study aims to develop a secure algorithm for encrypting Tele-Birr information using the enhanced Hill cipher technique with a symmetric key. The algorithm encrypts all Tele-Birr information using two keys k1, k2 in the form of a character matrix, generating a unique key for one-time encryption. Various cryptographic algorithms, such as Caesar cipher, Affine cipher, Vigenere cipher, and Hill cipher, have been created. By employing this symmetric key cryptography technique, all Tele-Birr information can be converted into unreadable messages using a combination of 131 additional characters and symbols. The enhanced encryption set consists of 141 characters, making the ciphertext extremely difficult for intruders to decipher due to the exponentially increased key space. This algorithm not only offers secure and efficient authentication but also ensures data confidentiality, integrity, nonrepudiation, and privacy. The performance analysis indicates that the proposed algorithm achieves better overall performance compared to existing Tele-Birr security solutions. This is due to the character changes and positional arrangement of matrix possible key space. The results were obtained using the Matlab simulation tool, which demonstrated an avalanche effect in the proposed algorithm.