Key-Based Coded Permutation ciphers with improved error performance and security in wireless channels

Abstract

Encryption is a vital process to ensure the confidentiality of the information transmitted over an insecure wireless channel. However, the nature of the wireless channel tends to deteriorate due to noise, interference and fading. Therefore, an encrypted signal will be received with some errors. Consequently, due to the strict avalanche criterion (SAC), these errors propagate during decryption resulting in half the bits (on average) after decryption to be in error. In order to alleviate these errors, smart coding and/or new encryption algorithms that take into account the nature of wireless channels are required. A modified version of the data encryption standard (DES) called M-DES is one proposed solution, where the error performance and security are improved. However, in M-DES half the cipher is not used to carry information, which degrades the throughput. In this work, we propose what we call the Key-Based Coded Permutation (KBCP), where we use hamming(7,4) codes in the remaining space of M-DES. Using computer simulations, we show that the use of KBCP on top of the first 16 rounds of M-DES significantly improves the error performance. In addition, we use numerical results to show that the use of KBCP enhances the security of the encrypted information.