An analysis and evaluation of lightweight hash functions for blockchain-based IoT devices

Blockchain is among the most promising new technologies due to its unique features, encompassing security, privacy, data integrity, and immutability. Blockchain applications include cryptocurrencies such as Bitcoin. Recently, many other applications have begun to deploy blockchain in their systems. These applications include internet of things (IoT) environments. Although deploying blockchain in IoT architecture has yielded numerous advantages, issues and challenges have arisen that require further research. Most IoT devices and platforms have limited storage capacity, low battery power, and limited hardware resources for computation and network communication. Thus, energy efficiency is a critical factor in these devices. On the other hand, blockchain requires extensive resources and high computational capabilities for mining and communication processes. Balancing computation complexity and IoT resources is a fundamental design challenge in implementing blockchain functions, including the hash function, which is crucial to blockchain design for the mining process. In this study, we present a literature review on the common hash functions used in blockchain-based applications, in addition to the lightweight hash functions available in literature. We evaluate and test the common lightweight hash functions (SPONGENT, PHOTON, and QUARK) on FPGA platforms to determine which is most suitable for blockchain-IoT devices. Moreover, we assess lightweight hash functions in terms of area, power, energy, security, and throughput. The results show tradeoffs between these hash functions. SPONGENT performs best on security and throughput. QUARK consumes the least power and energy but has the lowest security parameters. PHOTON utilizes less area and offers a balance between multiple performance metrics (area, energy, and security), rendering it the most suitable lightweight hash function.