  Due to successful applications of data analysis technologies in many fields,
various institutions have accumulated a large amount of data to improve their
services. As the speed of data collection has increased dramatically over the
last few years, an increasing number of users are growing concerned about their
personal information. Therefore, privacy preservation has become an urgent
problem to be solved. Differential privacy as a strong privacy preservation
tool has attracted significant attention. In this survey, we focus on improving
utility of between differentially private mechanisms through technologies
related to cryptography. In particular, we firstly focus on how to improve
utility through anonymous communication. Then, we summarize how to improve
utility by combining differentially private mechanisms with homomorphic
encryption schemes. Next, we summarize hardness results of what is impossible
to achieve for differentially private mechanisms' utility from the view of
cryptography. Differential privacy borrowed intuitions from cryptography and
still benefits from the progress of cryptography. To summarize the
state-of-the-art and to benefit future researches, we are motivated to provide
this survey.
