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（如数字孪生）依赖于从物联网(IoT)网络获取的传感数据，这些数据用于推断事件并触发影响环境的操作，由此引发了数据完整性和来源方面的担忧。解决这一问题的一种可行方案是采用区块链技术，然而区块链资源需求较高，不适用于资源受限的物联网设备。为此，本文提出了一种名为双层有向无环图(2LDAG)的新方法，其中物联网设备仅存储邻居节点生成数据的数字指纹。此外，本文提出了一种新颖的路径证明(PoP)协议，使操作员或数字孪生能够按需验证数据。仿真结果表明，与传统的区块链以及采用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和三个数量级。此外，即使49%的节点为恶意节点，2LDAG仍能达成共识。