Many online information platforms have arisen as an important business paradigm in order to serve the demands of society for person-specific data. These platforms are characterized by the fact that a service provider receives raw data from data contributors and then provides value-added data services to data consumers. The data consumers, on the other hand, are confronted with a significant dilemma at the data trading layer, which is the question of how to check whether the service provider has obtained and processed data in an honest manner. Additionally, the individuals that provide data are often hesitant to divulge their sensitive personal information as well as their true identities to the individuals who consume the data. TPDM is a proposal that we provide in this work. It is designed to incorporate Truthfulness and Privacy protection in Data Markets in and efficient manner. Internally, TPDM is organized in an Encrypt-then-Sign way, with partly homomorphic encryption and identity-based signatures being used.