At its most fundamental level, cryptography is about securing our digital communication and data. It’s becoming as indispensible as ever in modern society, particularly with millions of individuals as well as organizations and government turning to the cloud to store their data—from photos, to email, to sensitive documents. Take Dropbox, for example, which says it has more than 500 million registered users and over 300,000 teams using its business platform.
Securing the cloud is where Daniel Wichs comes in. Wichs, assistant professor in Northeastern’s College of Computer and Information Science, is an expert in cryptography who focuses his research on the security concerns emerging with the rapid rise of cloud computing—which utilizes remote servers with vast storage and computational resources.
Wichs’ work has garnered prestigious national recognition. He is now among the 126 U.S. and Canadian researchers to receive the 2018 Sloan Research Fellowships. The annual fellowships honor early-career scholars whose achievements mark them among the top scientific minds, according to the Alfred P. Sloan Foundation. The fellowships are presented to scholars in one of eight scientific and technical fields: chemistry, computer science, economics, mathematics, computational and evolutionary molecular biology, neuroscience, ocean sciences, and physics.
Wichs said that for years, though, users had to make a choice: keep their data encrypted—and thus, unusable—on the cloud, or “trust the cloud” to protect their data if they wanted to do things like search email or execute programs over their data. But he said that changed about a decade ago with the development of fully homomorphic encryption, which enables cloud computations without the cloud actually decrypting, or seeing, the data itself. “Think of it like the cloud is computing blindfolded,” Wichs explained.
Expanding upon fully homomorphic encryption is a particular focus of Wichs’ research. In fact, he and his colleagues developed the first “fully homomorphic signatures.” What this means is that someone could digitally sign his or her data and store it in the cloud, and when the cloud executes some program over the data it can derive a short signature to certify the output of the computation.
“The key is that the cloud data be both secure and functional,” he said.
Another focus of Wichs’ research is to expand fully homomorphic encryption to include multiple users. The idea is that you have several people or organizations who individually keep data in the cloud, and the goal is to pool that data together and find aggregate statistics or results. But the trick is that all that data would remain private and never be shared between those parties—or the cloud itself.
To illustrate this point, Wichs offered a theoretical example: let’s say you’ve got three hospitals, each of which keeps its patient data secured separately in the cloud, and you want to find an aggregate statistic across all three—say, how many patients across all three hospitals have a particular condition. Wichs’ work has shown how this can be theoretically done, and his goal going forward is to work on how these types of cloud computations can be done faster and more efficiently.
Wichs also explores the question of program obfuscation, which he calls “the holy grail of problems in cryptography.” Program obfuscation involves encrypting a computer program in way that allows someone else to use it, without learning anything about how the program is designed or implemented. For instance, perhaps there are some proprietary ideas or codes in the program, and you want to share that program without disclosing the intellectual property behind it. Wichs said there have been advances in program obfuscation in recent years, and he’s excited to push the limits further in this realm.
These types of real-world implications continue to drive his passion in his research. “The reason I love cryptography is that we’re addressing problems that are clearly practically motivated, and using cool ideas from math and computer science theory to solve them,” he said.