**9. Conclusions**

We proposed a novel privacy-preserving data aggregation approach for HANs in a smart grid in this paper. The proposed approach deploys a sink node between the household appliances and the smart meter, which not only filters false data injection attacks but also provides for early fault tolerance. The technology also combines data from several home appliances, which may belong to distinct subsets, into a single stream and sends it to the smart meter. The suggested technique is secure, and the performance evaluation reveals that it is more efficient in terms of communications and computation overhead than aggregation using basic Paillier encryption. Detecting and avoiding new threats, IDS architectures for smart grid privacy, IoT-driven smart grids, new privacy metrics, and privacy for IoT are all demanding research fields that need to be further explored in the future.

**Author Contributions:** Conceptualization, W.A., I.U.D., and A.A.; methodology, I.U.D. and A.A.; software, W.A.; validation, A.A.; formal analysis, I.U.D. and B.-S.K.; investigation, A.A. and B.-S.K.; resources, B.-S.K.; data curation, W.A.; writing—original draft preparation, W.A.; writing—review and editing, I.U.D. and A.A.; visualization, B.-S.K. and A.A.; supervision, I.U.D.; project administration, A.A.; funding acquisition, B.-S.K. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported in part by the National Research Foundation (NRF), Korea, under Project BK21 FOUR (F21YY8102068) and in part by King Saud University, Riyadh, Saudi Arabia, through Researchers Supporting Project Number RSP-2021/184.

**Acknowledgments:** This work was supported in part by the National Research Foundation (NRF), Korea, under Project BK21 FOUR (F21YY8102068) and in part by King Saud University, Riyadh, Saudi Arabia, through Researchers Supporting Project Number RSP-2021/184.

**Conflicts of Interest:** The authors declare no conflict of interest.
