  Intelligence is one of the most important aspects in the development of our
future communities. Ranging from smart home, smart building, to smart city, all
these smart infrastructures must be supported by intelligent power supply.
Smart grid is proposed to solve all challenges of future electricity supply. In
smart grid, in order to realize optimal scheduling, a Smart Meter (SM) is
installed at each home to collect the near real-time electricity consumption
data, which can be used by the utilities to offer better smart home services.
However, the near real-time data may disclose user's privacy. An adversary may
track the application usage patterns by analyzing the user's electricity
consumption profile. In this paper, we propose a privacy-preserving and
efficient data aggregation scheme. We divide users into different groups and
each group has a private blockchain to record its members' data. To preserve
the inner privacy within a group, we use pseudonym to hide user's identity, and
each user may create multiple pseudonyms and associate his/her data with
different pseudonyms. In addition, the bloom filter is adopted for fast
authentication. The analysis shows that the proposed scheme can meet the
security requirements, and achieve a better performance than other popular
methods.
