Partisia has been involved in developing Privacy-preserving Surveys based on secure multiparty computation (MPC) in different projects. The latest project is PKD where survey data on children in Denmark are collected in a secure system and stored on three different servers. These data are used to produce aggregate statistics via MPC and are therefore encrypted at all times.
Survey systems are used intensively to capture stated preferences from customers, employees, companies etc. In general, the revealed/public result from a survey is various statistics pointing at patterns or trends while individual answers are kept confidential. Traditionally, this level of confidentiality is ensured by consultants paid to take the role as trustee. There are also cloud based survey systems such as ”Survey Monkey” that allows users to conduct their own survey, though without any enforcements against leakages of confidential information.
MPC add values in two ways: First, the survey system is a distributed cloud computing system that does not provide the individual cloud services to access confidential information at any time (it is kept encrypted). Second, the control of the individual cloud computing instances (hosted by independent cloud service providers), are distributed among independent ”trustees”, each knowing no more than the individual cloud service provider. In this way we add value to existing cloud based surveys by a secure approach to cloud computing and by a built-in trustee function. For the traditional consultant, we add value by opening up for secure use of cloud computing and by the possibility of outsourcing the trustee role.
