LEOPARD: Lightweight Encryption Operation Permutation Addition Rotation and Diffusion

Tactical unmanned vehicles are commonly used to conduct tasks (e.g. monitor and surveillance) in various civilian applications from a remote location. The characteristic of the wireless communication link allows attackers to monitor and manipulate the operation of the unmanned vehicle through passive and active attacks. Cryptography is selected as a counter measure to mitigate these threats; however, a drawback of using cryptography is the impact on the energy consumed by the unmanned vehicle as energy is often constrained and limits the duration of the mission time. This paper introduces the Lightweight Encryption Operation Permutation Addition Rotation and Diffusion (LEOPARD) cryptographic primitive with a benchmark performance analysis against the standardised Advanced Encryption Standard (AES). Results indicate that LEOPOARD is a feasible encryption approach in comparison to the AES encryption algorithm for unmanned vehicles with an average performance increase of 8%.