A Comparison of Distributed Ledger Technologies in IoT: IOTA Versus Ethereum <Abstract> There is an increasing interest in adopting distributed ledger technologies (DLTs) to IoT applications that enable secured interaction between IoT devices without third-party involvement. Among recent advanced DLTs, Ethereum blockchain and IOTA Tangle are emerging as promising candidates for various IoT use cases. Both offer various IoT- friendly features such as lightweight crypto, open-source implementations, energy-efficient operations, etc. So far, the two technologies have only been qualitatively evaluated together in the literature. There has not yet been a performance comparison between IOTA and Ethereum in an IoT application. To address the issue, we build an IoT environment that can run both DLTs and compare their performance. We thoroughly investigate the DLTs' three layers (i.e., Consensus, Network, and Storage layers). In the first layer, we evaluate the CPU utilization and number of transaction; in the second one, the DLTs' network performance is compared. Meanwhile, disk and memory usage are derived in the third layer. The results show that IOTA performs better with most performance metrics. |