Mapping private keys into one public key using binary matrices and masonic cipher: Caesar cipher as a case study

Caesar cipher is a mono alphabetic cipher. It is also a type of substitution cipher in which each letter in the plaintext is “shifted” a certain number of places down the alphabet. However, Caesar cipher method did not last long because of its simplicity and lack of communication security. Therefore, we believe that strengthen the key mechanism should increase its complexity against the various cryptanalysis attacks. This paper proposes an enhanced Caesar cipher method through adopting two private keys that are tied to the character positions (i.e. odd and even) for encryption and/or decryption. The two private keys are mapped into one public key to be transferred to the recipient. At the end, the results show that the new cryptosystem is inevitable to cryptanalysis attack. And the cipher text is reduced in size and thus, memory space. The public key generation process is proven to be a one‐way function utilizing binary matrices that are generated and shared between the two communicating parties. Copyright © 2016 John Wiley & Sons, Ltd. The two private keys that are tied to the character positions for encryption and/or decryption are adopted to enhance the Caesar cipher method. The two private keys are mapped into one public key to be transferred to the recipient to produce a cryptosystem that is inevitable to cryptanalysis attack and to reduce the cipher text size and memory space.