Research On Security And Privacy Preservation Issues In Smart Grid

With the fast development of information and communication technology, China,US, Canada and many other countries have been modernizing their aging power system into smart grid. Smart grid is featured with two-way transmission, high reliability, realtime demand response, self-healing and consumer involvement, which shows substantial research and application importance. Security and privacy issues are crucial in the design and implementation of smart grid, which directly affect the normal operation of smart grid and acceptance of smart grid technologies.Smart grid is a complicated system from the point of view of its components, distribution area and design objects. With the development of smart grid all over the world,more and more security and privacy issues are emerging. Due to the complicity of smart grid and adoption of new technologies, the existed security and privacy preservation methods in the traditional network scenarios cannot be directly adopted. Therefore, it is meaningful and necessary to study new protection mechanism for smart grid. In this paper, we systematically investigate some key issues of security and privacy preservation in smart grid, especially on the privacy preservation of customer and group communication of key devices. The research mainly focuses on the following aspects:1. With the proliferation of smart grid, the metering data are surging dramatically and become a great burden of utilities. Outsourcing the metering data to cloud server is a promising approach and has the potential to make data access faster, cheaper, simpler and more standardized. In untrusted cloud environment, encrypting the sensitive metering data before outsourcing them to cloud server is a effective way to preserver the user’s privacy. However, how to efficiently query the encrypted multidimensional metering data is still challenging for smart grid. In this paper, we propose a privacy-preserving query(P2Q) scheme over encrypted multidimensional metering data to address this issue. The encrypted metering data are stored in the cloud server with ciphertext of their secret key. A Locality Sensitive Hashing(LSH) based similarity search approach is proposed to realize the similarity query and a prototype of the search approach has been implemented by Map Reduce for hadoop distribution environment. The proxy server will return K top similar data object IDs for a given query. An improved Ciphertext-Policy Attribute-based En-cryption(CP-ABE) policy are used to control the access of search results. Only the requester with authorized query attribute can work out the correct secret keys to retrieve the metering data. Security analysis demonstrates that the P2 Q can achieve data confidentiality and preserve the data owner’s privacy. Performance evaluation shows that the P2 Q can significantly reduce response time and provide high search efficiency without losing search quality, which make the P2 Q more suitable for massive data search in the cloud storage system.2. Vehicle to grid(V2G) is an important component of smart grid, which plays an irreplaceable role in fine-tuning the balance between the generation and consumption and promoting the adoption of clean energy. However, a significant barrier to the development of future V2 G technologies and services is the contradictory between the V2 G operators and the EV owners. Individual electricity vehicle(EV)owners fear data leakage and loss of privacy when personal sensitive information are processed in and transmitted across the V2 G infrastructure. In this paper, in order to securely monitor the EV status information without privacy leakage, we propose a secure communication protocol with privacy-preserving monitoring and controllable linkability for V2 G. In the proposed protocol, not only the location and identity privacy of EV can be protected, but also the sensitive information of the EV owner, such as expected time to leave, can be provided to the V2 G operators without exposing the exact values. The V2 G operators can customize statistic of EV users participating in V2 G system by linking keys without violating the EV users’ privacy, the statistic results can be used for scheduling optimization, rewarding the valuable EV owners and ejecting dishonest EV owners. The malicious users can be tracked with the help of trusted authority. Security analysis demonstrates that the the proposed protocol can preserve the identity and location privacy and sensitive information of EV owners. Performance evaluation shows that the communication cost and computation overhead of the proposed protocol is moderate for the onboard unit(OBU) in a vehicle and meet the time requirements of V2 G activation.3. In this paper, in order to simultaneously resolve the transmission security and availability in Supervisory Control And Data Acquisition(SCADA) group communications, we propose a robust and efficient group key management scheme, called SHDC, which is characterized by developing a secure self-healing mechanism witht-revocation and collusion resistance capability. A dual direction hash chain is utilized to guarantee the backward secrecy and forward secrecy of group key. A novel self-healing mechanism is constructed to ensure availability of the group member in case of devices failure, and prevent the collusive users from exploiting the group key in the proposed scheme. In addition, the compromised users can be revoked from the group dynamically by broadcasting message. Detailed security analysis shows that the proposed SHDC scheme meets the requirements of group communication and is secure in terms of t user collusion-free. Performance evaluation also demonstrates its efficiency in terms of low storage requirement and communication overheads.4. Wireless sensor networks are widely used in smart grid for their cheap price, high performance and convenient maintenance. In this paper, in order to simultaneously resolve the transmission security and scalability in wireless sensor network group communications, we propose a hierarchical cluster-based secure and scalable group key management scheme, called HRKT, based on logic key tree and route key tree structure. The HRKT scheme divides the group key into cluster head key and cluster key. The cluster head generates a route key tree according to the route topology of the cluster. This hierarchical key structure facilitates local secure communications taking advantage of the fact that the nodes at a contiguous place usually communicate with each other more frequently. In HRKT scheme, the key updates are confined in a cluster, so the cost of the key updates is reduced efficiently, especially in the case of massive membership changes. A lazy update strategy is further leveraged to decrease the rekeying cost with acceptable delay. The security analysis shows that the HRKT scheme meets the requirements of group communication.In addition, performance simulation results also demonstrate its efficiency in terms of low storage and flexibility when membership changes massively.To summarize, this paper investigates two essential issues of smart grid, i.e., customer privacy and group communication of key devices, and provides novel solutions.The perfomance evaluation and security analysis all show that the proposed algorithm can properly achieve the design goals.