A Performance Comparison of Hashed and Authenticated Advanced Encryption Standard

The present era is witnessing IoT as a promising upcoming field affecting almost all spheres of human lives. However, IoT is facing more significant challenges due to the constrained nature of the devices. The most crucial challenge that hinders its widespread applicability is security. The exponential rise in security attacks necessitates ensuring the confidentiality, integrity and authentication of transmitted data sensed by these resource-limited devices. Although the new field of lightweight cryptography is attempting to secure low-end devices, conventional AES block cypher is still preferred due to the absence of standard lightweight crypto primitive addressing all three security aspects. Moreover, various integrity and authentication attacks can still compromise the encrypted data, which justifies the need for hashing and MAC algorithms. In this paper, two hashing (MD5 and SHA-256) and one authentication (HMAC) techniques available in the standard and well-tested ARM mBed TLS library have been used with the AES block cypher to achieve multi-level security. All these primitives have been implemented in KEIL MDK IDE and on ARM Cortex-M3-based LPC1768 hardware development IoT platform. Moreover, these primitives have been analysed and compared in real-time regarding various design metrics such as execution time, memory footprint, power and energy consumption using ULINKpro and ULINKplus debug adapters. The results aid the designers in selecting proper encryption, hashing and MAC algorithms per the availability of resources with various IoT development platforms.