A Novel Secure Transposition Cipher Technique using Arbitrary Zigzag Patterns

Abstract

Symmetric cipher cryptography is an efficient technique for encrypting bits and letters to maintain secure communication and data confidentiality. Compared to asymmetric cipher cryptography, symmetric cipher has the speed advantage required for various real-time applications. Yet, with the distribution of micro-devices and the wider utilization of the Internet of Things (IoT) and Wireless Sensor Network (WSN), lightweight algorithms are required to operate on such devices. This paper proposes a symmetric cipher based on a scheme consisting of multiple zigzag patterns, a secret key of variable length, and block data of variable size. The proposed system uses transposition principles to generate various encryption patterns with a particular initial point over a grid. The total number of cells in the grid and its dimension are variable. Various patterns can be created for the same grid, leading to different outcomes on different grids. For a grid of n cells, a total of n! * (n-1!) total patterns can be generated. This information is encapsulated in the private key. Thus, the huge number of possible patterns and the variation of the grid size, which are kept hidden, maintain the security of the proposed technique. Moreover, variable padding can be used; two paddings with different lengths lead to a completely different output even with the same pattern and the same inputs, which improves the security of the proposed system.