Participatory sensing is a revolutionary new paradigm where ordinary citizens voluntarily sense their environment using readily available sensor devices such as mobile phones and systematically study, and then reflect on and share this information using existing wireless networks. It provides data collection, processing, and dissemination opportunities for socially-responsible applications spanning environmental monitoring, intelligent transportation, and public health, which are often not cost-viable using dedicated sensing infrastructure. The uniqueness of the participatory sensing system lies in its data communication infrastructure which is constituted by the deliberate participation of community people. However, the potential lack of privacy of the participants in such system makes it harder to ensure their voluntary contribution. Thus preserving privacy of the individuals contributing data has introduced a key challenge in this area. On the other hand, data integrity is desired imperatively to make the service trustworthy and user-friendly. Different interesting approaches have been proposed so far to protect privacy that will encourage participation of the owners of data sources in turn.