Decentralizing services like finance and social media could bring real advantages, said Prateek Mittal, but underwhelming results from similar efforts show how hard it can be.

Mittal, a professor of electrical and computer engineering, points to 20 years of work by colleagues to design distributed versions of social media and a decade of work by himself and others to decentralize the tools that keep people’s data safe and private.

“We figured out an architecture for decen-tralized services like social networks. We figured out multiple implementation details, but there was not much movement that happened in the real world,” said Mittal, who is interim director of the University’s Center for Information Technology Policy and a member of the DeCenter steering committee.

One decentralized system that did develop a significant user base is Tor, a network that harnesses the distributed power of computers worldwide to anonymize internet traffic. “The Tor network is used by millions of individuals. Well, the internet user population is billions,” Mittal said.

The challenge, Mittal said, often boils down to incentives. In centralized systems, a company or a government can use money or regulatory power to shape and govern networks. Companies serve ads, collect fees, and sell data. In decentralized systems, which often require effort by users, incentives are less clear.

That is where blockchain technologies could help, Mittal said. “One of the key innovations of the blockchain ecosystem is they managed to figure out an incentive for people to participate.” Bitcoin, for example, offers users currency in exchange for the computing power — and expenditure of electricity — needed to secure the system.

Blockchain technologies can enable applications while minimizing trust in a single entity. Consider a system for secure online identities where users gain status when other users rate their contributions. Status-based systems already exist, such as the online forum Reddit or the ride-share service Uber. But these systems work because all sides trust a central corporation to manage the data.

Blockchain could help decentralize such systems, Mittal said, but raises a host of other challenges. How do you keep it secure in an equitable and environmentally sustainable way? Who is responsible for making sure things work, and what incentive do they have for doing so?

“Ultimately, a lot of the centralized services we rely on have a simpler pathway for deployment,” he said. “But if services are decentralized, there’s no central coordinator. We have to think about making sure the system operations are correct and robust. That they don’t fail in the face of malicious actors. That’s a grand challenge.”