Elixir: A 128-bit Stream Cipher Protocol for Lightweight IoT Devices

Over time, the Internet of Things (loT) has turned out to be most prevalent in the field of research and its applications. However, IoT devices are resource constraints and thus, require lightweight and secure ciphering protocols. This paper proposes a new lightweight stream cipher algorithm named as `Elixer', based upon classical 128-bit non-linear feedback shift register technique. This stream cipher is based on static and dynamic substitution-boxes with shift operations and results in an output keystream. Confusion and diffusion properties are added with the help of substitution and transposition techniques respectively. In the core design of Elixir, there are eight static 6 x 8 s-boxes and two dynamic s-boxes. The correctness of the proposed stream cipher is tested according to NIST randomness standards and Stream tests. Elixir is designed to be implemented easily and efficiently for both Hardware and Software implementations.