Building Privacy-Preserving Systems

Johes Bater (PhD ‘20) furthered his research into privacy-preserving systems at Northwestern Engineering, also learning how to effectively communicate about his work with various audiences.

Bater is an assistant professor of computer science at Tufts University. Previously, he was a postdoctoral research associate with the Database Group at Duke University. Bater earned his PhD in computer science under the supervision of Jennie Rogers, associate professor of computer science at Northwestern Engineering. He earned both a bachelor’s and master’s degree in electrical engineering at Stanford University.

Bater’s research centers on the intersection of security, privacy, and performance — including privacy-preserving analytics, federated databases, differential privacy, private data sharing, secure computation, database performance, data science, and trustworthy database systems.

Bater was asked about his research interests, impactful collaborative experiences at Northwestern CS, and his advice for current students.

Why did you decide to pursue your PhD at Northwestern CS?

I chose to pursue my PhD at Northwestern CS for a couple of reasons, both research and non-research related. First off, I felt like I had a great connection with my adviser, Jennie Rogers, when I spoke with them and I was very excited about their research direction, even though we actually ended up pivoting away from it a fair amount. Second, I love the city of Chicago and how I could do so many things outside of the University when I needed time to reset or recover from a particularly demanding project. Overall, I chose Northwestern CS because it was a supportive environment that let me work in an effective, sustainable way.

Could you describe your research interests in one sentence?

My research centers on how to build database management systems that help people retain ownership of their private data, while still benefiting from the many advances in large-scale data analytics.

What was the focus of your thesis project?

I worked on how to balance privacy, security, and utility when building database management systems. Instead of siloing sensitive data in black boxes distributed across many isolated data owners, my work centered on building a fast, accurate system for privacy-preserving analytics that brings together this fractured data through a combination of cryptography, differential privacy, and query optimization.

What are some examples of collaborative experiences at Northwestern that were impactful to your research?

Through our amazing partners at Northwestern Medicine like Abel Kho, my adviser and I were able to apply our work to electronic health records and actual queries used for medical research. Our goal as researchers is to contribute to knowledge and ultimately help people live better lives. Seeing all the unexpected issues and problems that popped up when carrying out the project was definitely frustrating. However, it really helped me understand all the work that is needed to take a research project and actually apply it in a functional setting where it can make a difference in people’s lives.

What skills or knowledge did you learn in the PhD program that you think will stay with you for a lifetime?

One of the most valuable things I learned in the PhD program was how to communicate topics at different resolutions. How I describe a project to a research collaborator, a friend, or my parents needs to be very different. I didn’t know how to do that well when I first arrived at Northwestern, and it led to a lot of problems explaining what I did and why it mattered. Going through the program helped me figure out how to optimize my communication to maximize how much the other person gets out it rather than spending time going over information that they don’t need or want to know.

What types of research and projects did you work on at Duke University and what projects are you looking forward to continuing and launching at Tufts University?

Right now, I’m working on a couple different research directions. I worked with the Database Group at Duke on privacy for cloud-based database management systems where new information is constantly uploaded by users. At Tufts, I’m very excited to continue my research on building privacy-preserving systems as well as collaborating with my colleagues on seeing how those systems actually work with real people and how we can improve how people use them for real tasks.

What are your longer-term career goals?

At the moment, I’m focused on doing interesting research and communicating all the cool results that come out of it. Longer-term, I want to continue producing research and seeing all the ways it can change how organizations interact with privacy.

What advice do you have for current Northwestern CS PhD students?

I’d advise current Northwestern CS students to focus not just on the research component of their work, but also the social component. Communicating results, getting inspiration, and just refreshing your mental state are difficult to do if you’re isolating yourself from your community. Finding a good balance really helped me produce better work and opened future opportunities as well.