Design of a Lightweight Hash Function for Highly Constrained Devices

Abstract

The Internet of Things (IoT) plays a crucial role in people’s everyday lives such as in smart environments and healthcare applications. In general, IoT devices have limited resource architecture which increases the vulnerability to cyberattacks. The security of these devices and the stored data demand the design of lightweight cryptographic hash functions.

Cryptography hash function is vital to cyber security applications. It is used to verify data integrity, authenticate files, and detect any modifications applied to them during data in transit or data at rest. Common applications of hash functions include cryptocurrency, message security and password security. In cryptocurrencies, cryptographic hash functions are used to process transaction details anonymously. One example is Bitcoin, the largest cryptocurrency, which heavily relies on the SHA-256 hash function.

Many standard hash function algorithms including SHA-3, SHA-1 and MD-5 have been developed over the past decades for unconstrained devices. However, in the era of IoT, the design of lightweight cryptography for highly constrained devices is needed. This requires a trade-off between security, cost, and performance. Constrained devices have limited power and storage, making it challenging to run large and complex algorithms. Due to the limitation of conventional hash functions in constrained devices, the problem of designing a lightweight hash function for highly constrained devices has gained a great deal of attention.

This MSc work presents the design and implementation of a lightweight hash function suitable for highly constrained devices. The proposed lightweight cryptographic hash function is called the 2DC that is AES-like function based on a wide present-type permutation. The name “2DC” is derived from satisfying the diffusion and confusion properties of cryptographic algorithm.

The work progresses from the design choice to the software implementation and finally to the security analysis. The specific requirements of memory size and execution time are considered in the design phase. In addition, the desired security and performance properties are also analyzed. The main challenge is to balance security requirements with performance considering the resource limitations of the highly constrained devices. However, the desired requirements are achieved by implementing the 2DC design that uses an iterated substitutions and permutations layers, which satisfies the cryptographic properties and provides diffusion at a low cost.

The performance of the proposed hash function is tested and validated on constrained microcontrollers. Several scenarios are considered to simulate real-world scenarios such as varying input-size and applying cryptanalysis. In terms of security and performance measures, the proposed algorithm successfully meets the requirements of a lightweight hash function when deployed on IoT devices.

Date of Award	13 May 2024
Original language	American English
Supervisor	YOUSUF ALSALAMI (Supervisor)