DATA SHARING SYSTEM, DATA SHARING METHOD, AND DATA SHARING PROGRAM

In a data sharing system, the data possessed by the others is utilized safely without disclosing the contents of the data to the others. A data sharing system of the present disclosure includes a plurality of data providing devices; a key management device; a proxy device and a calculation device, wherein the key management device includes a key management unit configured to manage a system key, each of the plurality of data providing devices includes: a first sensitive data acquisition unit configured to acquire a sensitive data; and an encryption unit configured to encrypt the sensitive data by a predetermined encryption scheme using a user key which is different from the system key, the proxy device includes: a second sensitive data acquisition unit configured to acquire the encrypted sensitive data from the plurality of data providing devices; and a conversion unit configured to execute a conversion of the acquired sensitive data into the sensitive data in a predetermined encryption space based on the system key, and the calculation device includes an execution unit configured to execute a secure computing based on the converted sensitive data.