LILP: A Lightweight Enciphering Algorithm to Encrypt Arbitrary-Length Messages.

The advancement of the Internet of Things (IoT) has promoted the development of embedded devices. It is important to ensure data transmission security on embedded devices with limited computing power and storage space. However, the traditional block encryption algorithm cannot run efficiently on embedded devices because of the large amount of computation. In this paper, a lightweight length-preserving-encryption algorithm (LILP) is proposed to convert an n-bit block cipher into a special block cipher that supports an arbitrary length of no less than 2n bits as input. LILP adopts the involution design method based on a Lai-Massey structure and lightweight components to adapt to the limited computing power of embedded devices. In particular, a lightweight compression function (LCF) is designed to process the data during iteration, which improves security without reducing the efficiency of the algorithm. The experimental results show that LILP is more efficient than traditional similar algorithms in encrypting data for resource-constrained devices while ensuring data security in the IoT.