Many applications, e.g., digital twins, rely on sensing data from Internet of Things (IoT) networks, which is used to infer event(s) and initiate actions to affect an environment. This gives rise to concerns relating to data integrity and provenance. One possible solution to address these concerns is to employ blockchain. However, blockchain has high resource requirements, thereby making it unsuitable for use on resource-constrained IoT devices. To this end, this paper proposes a novel approach, called two-layer directed acyclic graph (2LDAG), whereby IoT devices only store a digital fingerprint of data generated by their neighbors. Further, it proposes a novel proof-of-path (PoP) protocol that allows an operator or digital twin to verify data in an on-demand manner. The simulation results show 2LDAG has storage and communication cost that is respectively two and three orders of magnitude lower than traditional blockchain and also blockchains that use a DAG structure. Moreover, 2LDAG achieves consensus even when 49\% of nodes are malicious.

翻译：---- 许多应用，例如数字孪生，依赖于来自物联网网络的传感数据，用于推断事件并启动影响环境的操作。这引起了与数据完整性和溯源相关的关注。解决这些问题的一种可能的方法是使用区块链。然而，区块链具有高资源要求，因此不适用于资源受限的物联网设备。为此，本文提出了一种新的方法，称为双层有向无环图（2LDAG），其中物联网设备仅存储其邻居生成的数据的数字指纹。此外，提出了一种新的路径证明（PoP）协议，允许运营商或数字孪生以按需方式验证数据。仿真结果显示，与传统区块链以及使用DAG结构的区块链相比，2LDAG的存储成本和通信成本分别降低了两个数量级和三个数量级。此外，2LDAG即使有49％的节点是恶意的，也可以实现共识。