LICID: a lightweight image cryptosystem for IoT devices

Abstract

In this paper, we highlight the limitations of block cipher modes of encryption ECB, CBC, OFB and CTR to cipher multimedia content and when they are implemented in IoT devices. In fact, processing multimedia encryption with classical IoT methods like Present, Simon, Rectangle and others does not provide enough confusion and diffusion even though they are specially designed for IoT devices. Those lightweight cryptosystems are designed for text or binary data and cannot fulfill high security levels when used with multimedia data. We introduce LICID, a new lightweight cipher specially designed for image data that can be implemented in low resource devices, making it the first attempt to resolve multimedia security in IoT context. LICID is based on a new structure “outer–inner structure.” This new structure is specially designed to treat high correlation and redundancy of image and to ensure the highest level of confusion and diffusion properties. We also provide a detailed cryptanalysis of LICID by testing its robustness against linear and differential attacks. We show that the linear attack complexity is 2116 for the 14th round of LICID and the differential attack complexity is for just the 8th round. In both cases, the most two powerful known attacks exceed the brute force search, which is 2112, making LICID theoretically secure.