This data exchange protocol is being developed to be as general as possible, so that not only the healthcare data but also all the other types of data can be handled by the protocol. Since Panacea and data exchange protocol is publicly opened, any service providers can build their own services on the top of the data exchange protocol, so that their users can exchange their data securely and get proper rewards. As the first use case, MediBloc is going to build a healthcare data marketplace service based on this protocol. Well, it sounds like the protocol should work well, right? However, there are so many issues that we have to resolve. For privacy and security, data sellers should be able to expose only a small part of their data that is really desired by data buyers. Data transmission must be secure, so that anyone cannot steal data. In order to guarantee the right of data buyers, all criteria that data buyers specified has to be validated clearly before the payment is finalized. In addition, the ecosystem should be attractive enough for many data sellers and buyers to join.