Searches can always be revealing. Searches for direction disclose our location, checking for a password in a pile of compromised data and we risk leaking it ourselves.
This leads to an important question in cryptography – how can you get information from a public database without revealing anything about what you’ve accessed? How do you borrow a book from the library without the librarian knowing about it.
A solution to this problem was the private information retrieval which is described as a“ very useful building block in a number of privacy-preserving applications,” said David Wu, a cryptographer at the University of Texas, Austin. Since the 1990s, researchers have been trying to answer this question about privately accessing databases. The major goal of this research is to be able to do it with large databases like a private google search.
Three researchers have crafted an extensive understanding of private information retrieval and how to extend it to build more general privacy strategy. This project received the Best Paper Award in June 2023 at the annual Symposium on Theory of Computing. This breaks through a major theoretical barrier in the way of truly searching privately.
“[This is] something in cryptography that I guess we all wanted but didn’t quite believe that it exists,” said Vinod Vaikuntanathan, a cryptographer at the Massachusetts Institute of Technology who was not involved in the paper. “It is a landmark result.”
After creating this model, the authors have moved on to try it in the real world. But making a private internet search in the real world isn’t easy, it is much more complicated that pulling bits of information from a database.
But this discovery is a milestone for research in cryptography. To enable users to truly privately search would fulfil one of the major goals of these researchers.