Group signature schemes enable anonymous-yet-accountable communications. Such a capability is extremely useful for modern applications such as smartphone-based crowdsensing and citizen science. A prototype named GROUPSENSE was developed to support anonymous-yet-accountable crowdsensing with SRBE in Android devices. From this prototype, an Android crowdsensing application was implemented to support privacy in citizen science. In this thesis, we will evaluate the usability of our privacy-preserving crowdsensing application for citizen science projects. An in person user study with 22 participants has been performed showing that participants understood the importance of privacy in citizen science and were willing to install privacy-enhancing applications, yet over half of the participants did not understand the privacy guarantee. Based on these results, modifications to the crowdsensing application have been made with the goal of improving the participants' understanding of the privacy guarantee. / Master of Science / A group signature scheme is a security solution that allows any member of a group to create a digital signature without revealing his or her identity. This enables an application user to remain anonymous-yet-accountable during communication. Such a capability is extremely useful when collecting data for scientific research, referred to as citizen science, through a modern smartphone application. A prototype named GROUPSENSE was developed to support anonymous-yet-accountable data collection with SRBE, an advanced group signature scheme, in Android devices. From this prototype, an Android application was implemented to support privacy in citizen science. In this thesis, we will evaluate the usability of our privacy-preserving application developed for citizen science projects. An in person user study with 22 participants has been performed showing that participants understood the importance of privacy in citizen science and were willing to install privacy-enhancing applications, yet over half of the participants did not understand the specified privacy guarantee. Based on these results, modifications to the application have been made with the goal of improving the participants’ understanding of the privacy guarantee.

Crises are spontaneous and highly variable events that lead to life threatening and urgent situations. As such, crisis and emergency notification systems need to be both flexible and highly optimized to quickly communicate to users. Implementing the fastest methods, however, is only half of the battle. The use of geospatial location is missing from alert systems utilized at university campuses across the United States. Our research included the design and implementation of a mobile application addition to our campus notification system. This addition is complete with optimizations including an increase in the speed of delivery, message differentiation to enhance message relevance to the user, and usability studies to enhance user trust and understanding. Another advantage is that our application performs all location data computations on the user device with no external storage to protect user location privacy. However, ensuring the adoption of a mobile application that requests location data permissions and relating privacy measures to users is not a trivial matter. We conducted a campus-wide survey and interviews to understand mobile device usage patterns and obtain opinions of a representative portion of the campus population. These findings guided the development of this mobile application and can provide valuable insights which may be helpful for future application releases. Our addition of a mobile application with geospatial location awareness will send users relevant alerts at speeds faster than those of the current campus notification system while still guarding user location privacy, increasing message relevance, and enhancing the probability of adoption and use. / Master of Science