*3.2. Microchain Fabric for UAM Data Sharing*

As the right part of Figure 1 shows, a microchain fabric consists of two sub-systems: (i) a lightweight consensus protocol that relies on a randomly selected consensus committee to achieve a low latency when committing transactions on the distributed ledger; (ii) a hybrid on-chain and off-chain storage strategy that improves efficiency and privacypreservation. For details regarding the consensus protocol in the microchain, interested readers can refer to our earlier work [23,34]. The core functionalities and workflows are briefly described as follows:


#### **4. Experimental Results and Evaluation**

In this section, experimental configuration based on a proof-of-concept prototype implementation is described. Following that, we evaluate the performance of running LightMAN based on numerical results, which especially focus on microchain operations. Finally, a comparative evaluation among previous work highlights the main contributions of LightMAN in terms of lightweight blockchain design, performance improvement, security, and privacy properties.
