  In smart grid, the Utility Provider (UP) collects users power measurements'
for two main reasons: billing and operation. Billing needs coarse-grained
measurements where there are no, or minimal, privacy concerns. On the other
hand, operation needs fine-grained measurements which can highly affect users'
privacy. Hence, users might be reluctant to participate in operational metering
to protect their privacy. To overcome this issue, UP might offer rewards to
allure users to report their measurements which endangers their privacy. In
this paper, we survey the literature on privacy-preserving metering in smart
grid. We propose a new taxonomy to categorize the literature based on whether
measurements need to be attributable to users or not. This categorization is
highly effective because attribution is one of the main causes of privacy
issues. Our survey shows that rewarding schemes and incentive-based demand
response are new research topics with limited studies on it. Hence, we propose
two privacy-preserving rewarding schemes for operational metering. First, a
light-weight solution that utilizes an already established link of trust i.e.
Banks. It is based on the assumption that banks will not leak a client account
details. This solution is based on hash chains and blind signatures to assure
users anonymity with minimal overhead for the UP and the smart meter. The bank
in this approach is state-less in which is not required the bank to keep
communications states of users and the UP. Second, we proposed another approach
that does not rely on or banks or trusted third parties. It is based on
Paillier homomorphic encryption and Pedersen commitments. It assumes that the
smart meters are organized in a tree structure; which is widely used
implementation in the literature. Security analysis for the proposed approaches
is presented including unlinkability proof for measurements to users.
