Design and Implementation of Privacy-Preserving Billing on Smart Grid

近年來，世界各國積極佈建智慧電網。但是為了數據匯總和計費等要求，用戶必須提供其詳細用電讀數。但這些數據會洩漏用戶的生活模式。而除了隱私問題之外，竊電事件也不斷地發生。直接從智慧電錶提供電費雖然可以保護詳細用電模式，但對於竊電的用戶來說，直接給出最終賬單顯然很難察覺竊電行為。我們試圖將現有的隱私保護數據聚合方法及隱私保護竊電檢測方法做結合，收集聚合用的數據，待它們被檢測通過。即可使用這些用電訊息產生電費帳單。此外，我們添加了差分隱私雜訊以允許電力供應商統計用戶的電費，同時確保用戶用電活動的隱私。與之前的差分隱私計費機制相比，我們設計了一個機制，使雜訊總和為 0，使其不影響電費。並藉由檢查雜訊總和是否達到 0，防止用戶透過篡改雜訊竊電。以現有智慧電錶設備來說，其資源和計算能力有限，我們所設計的計費機制僅 花費最終的一次性計算成本。而用電數據的密文與來自用於聚合的密文。值得注意的是，我們已經在現有的智慧電錶產品中實施了這一機制，測試了可用性和運算效率，提供了結算電費與竊電檢測的初步結合，避免發送難以檢查的數據。In recent years, the deployment of smart grids has been actively promoted by several countries. However, in order to get data aggregation and billing requirements. Users must provide fine-grained data, which will leak user’s lifestyle. However, except the privacy issues energy theft events also occur one after another. Providing electricity bills directly from smart meters can protect the privacy of electricity data, but for users who launch energy theft. The final bill is obviously hard to detect. We try to combine the previous privacy preserving data aggregation method with the existing privacy preserving energy theft detection method, and collect the data which transmitted for the data aggregation purpose. When it is detected, then using this information to generate the electricity bill. In addition, differential privacy noise is added to allow electricity providers to statistic user’s electricity bill while ensuring user privacy. Compared with the previous differential privacy billing mechanism. We designed a mechanism, which let the summation of noises to be 0. So that noise does not affect the electricity bill. By checking whether the noise sums up to 0. It prevents users stealing power by tampered noise. Because existing meter devices have limited resources and computing ability. Our billing mechanism overhead only the final one-time batch computation cost. The cipher text of the energy consumption can be seen as sharing with data aggregation purpose. It is worth noting that we have implemented the mechanism in existing smart meter products. Testing the availability and measurement efficiency, and provided a direction for combining billing and power theft to avoid sending difficult-to-check data.摘要 i Abstract ii Contents iii List of Figures v List of Algorithms vi Chapter 1 INTRODUCTION 1 1.1 Smart grid and smart grid application 1 1.2 Issue of data privacy in smart grid 1 1.3 Research gap 2 1.4 Contribution 2 Chapter 2 RELATED WORK 4 Chapter 3 PROPOSED METHOD 5 3.1 PROPOSED METHOD 5 3.1.1 Privacy-preserving billing with honest meters 5 3.1.2 Privacy-preserving billing with malicious meters 9 3.2 EXPERIMETS 11 3.2.1 Environment setting 11 3.2.2 Problem solving 12 3.2.3 The cryptographic system 13 3.2.4 Noise creating 15 Chapter 4 CONCLUSIONS 18 References 19 Appendix 2