Energy big data: A survey <s> 2) SECURE AGGREGATION BY SMART METERS <s> Cyber security for smart grid communication systems is one of the most critical requirements need to be assured before smart grid can be operationally ready for the market. Privacy is one of very important security consideration. The customer information privacy in smart grid need to be protected. Smart grid data privacy encompasses confidentiality and anonymity of the information extracted from smart device metering transmission in smart grid communication system. In this paper, we consider a home area network as a basic reading data aggregation and dispatch unit in smart grid systems. Then, we propose a secure in-network data aggregation and dispatch scheme to keep the confidentiality and anonymity for collecting power usage information of home smart devices to the household smart meter and the reverse control message distributing procedure. Specifically, we introduce an orthogonal chip code to spread reading-data of different home smart devices into spread code, followed by a circuit shifting operation to coupling neighboring smart devices tightly. We adopt an in-network mechanism to further mask it with its spread data with its forwarding data. Finally, we analyze the cyber security protection levels using an information theoretic quantity, residual uncertainty. Simulation studies are conducted to test the performance on different metering datasets for the proposed scheme. This paper sets the ground for further research on optimizing of home power management systems with regarding to the privacy of customer power usage behaviors. <s> BIB001 </s> Energy big data: A survey <s> 2) SECURE AGGREGATION BY SMART METERS <s> We propose a decentralized security framework for smart grids that supports data aggregation and access control. Data can be aggregated by home area network (HAN), building area network (BAN), and neighboring area network (NAN) in such a way that the privacy of customers is protected. We use homomorphic encryption technique to achieve this. The consumer data that is collected is sent to the substations where it is monitored by remote terminal units (RTU). The proposed access control mechanism uses attribute-based encryption (ABE) which gives selective access to consumer data stored in data repositories and used by different smart grid users. RTUs and users have attributes and cryptographic keys distributed by several key distribution centers (KDC). RTUs send data encrypted under a set of attributes. Since RTUs are maintained in the substations they are well protected in control rooms and are assumed to be trusted. Users can decrypt information provided they have valid attributes. The access control scheme is distributed in nature and does not rely on a single KDC to distribute the keys which makes the approach robust. To the best of our knowledge, ours is the first work on smart grids, which integrates these two important security components (privacy preserving data aggregation and access control) and the first paper which addresses access control in smart grids. <s> BIB002
In power network, data can be aggregated through Home Area Network (HAN), Building Area Network (BAN), and Neighboring Area Network (NAN) in the way that customers' privacy is protected BIB001 . For each HAN, there is a gateway smart meter called han which collects and sends information to the BAN. The gateway smart meter ban in BAN aggregates these information and sends them to the gateway smart meter nan in the neighborhood area. Finally, nan in NAN reports all the information to the data repository which is monitored by the Remote Terminal Unit (RTU). Ruj and Nayak BIB002 proposed a new decentralized security framework to keep the whole aggregation process safe. The i-th RTU R i in data repository is securely given a public key PK han j in HAN sends a data packet that consists of two fields: the attribute field a and the power consumption field p j corresponding with different attributes. The power consumption field can be encrypted with the data repository public key. Then the packet can be described as: , where PPK [han j ] is short for the packet sent by smart meter gateway han j and r j ∈ Z * n is randomly chosen by the smart meter. The attribute field will be checked in BAN. When the packet is sent to the BAN, the gateway ban l will aggregate all the packets which have the same set of attributes into a new packet and process the aggregated power consumption. This aggregated result can be given by: c ban l = han j ∈HAN c han j . The new packet can be described as: Packets aggregated by a set of gateway smart meters {ban 1 , ban 2 , · · · , ban j } then will be sent to the NAN. The NAN gateway nan k aggregates the packets and operations the information at the same way of ban. The aggregated result can be figured out by: c nan k = ban l ∈BAN c ban l . The new packet PPK [nan k ] = a||c nan k will be sent to the nearest data repository. The RTU R i in the data repository will receive packets and decrypt the encrypted results by using its secret key SK [i] . Thus the RTUs can aggregate information without knowing what exact data was send by the smart meters at the HANs. The whole aggregation progress is similar to a spanning tree, where the HAN is at the bottom and data repository is at the top.