Audrey Woods, MIT CSAIL Alliances | August, 11, 2025
Most of us think of cryptography as a means of ensuring information security. We associate the field with blockchain technology or encrypted messaging services like Signal or Telegram. But MIT CSAIL Professor Yael Kalai wants people to know that cryptography is so much broader. Modern cryptography is critical for challenges like verifying correctness of computation, preparing for a future of quantum computing, and creating more robust and reliable AI programs.
As co-leader of the Cryptography and Information Security Group at CSAIL, Professor Kalai is leveraging her fascination with mathematics to address these challenges, offer new solutions, and explore what’s possible with the power of cryptography.
AN UNLIKELY COMPUTER SCIENTIST
“I feel like I was born loving math,” Professor Kalai says, explaining how, even as a child, she had a deep desire to understand math and everything related to it. While studying mathematics as an undergraduate she was in love with its beauty and deeply content “just doing math all day long.” However, as she began to investigate higher education options, she was shocked by how little she was drawn to math research. As much as she enjoyed learning the subject, she wasn’t at all excited by the work happening in the field.
Adrift and unsure of what to do next, Professor Kalai took a semester off to think about her future. By chance, at one of her brother’s school performances, she sat next to a woman who recommended she try out computer science at the Weizmann Institute of Science in Israel. Having taken no computer science courses and with no experience or interest in coding and programming, Professor Kalai thought the advice was ridiculous. But when her father, who also worked in academia, echoed the woman’s advice, she applied and was accepted for the next semester. “I started studying there and it was amazing, because it was basically math but in disguise as computer science.”
While at Weizmann, Professor Kalai studied under Adi Shamir, a Turing Award Winning Israeli Professor of Applied Mathematics and Computer Science who taught applied cryptography. “I’m not very interested in applied things; I’m much more into theory,” she admits, but she enjoyed him so much as a teacher that she ended up writing her thesis with him as her advisor. Soon after, she met MIT CSAIL Professor and 2012 Turing Award Winner Shafi Goldwasser, whose interest in theory aligned even more deeply with her own. After beginning her PhD at Weizmann, she transferred to MIT to formally finish her degree working with Professor Goldwasser.
To this day, Professor Kalai still doesn’t code. When she won the prestigious 2022 ACM Prize in Computing, her children teased her that it must be a joke. But Professor Kalai’s significant contributions to the field of cryptography don’t need her to understand programming or coding languages. They rely mainly on math, and she’s perfectly happy with that.
THREE TRENDS IN CRYPTOGRAPHY & RESEARCH TO ADDRESS THEM
Cryptography might be a niche of computer science, but that doesn’t mean it’s isolated from the trends shaping the field as a whole. For example, the single biggest change that Professor Kalai has seen in her career—and one of her main research areas—is the enormous challenge of big data. When she first started studying at Weizmann, the main focus was securely sending information, ensuring confidentiality, and supporting innovations like digital signatures. Then the era of big data came along, and with it, an enormous need for cloud computing. As users increasingly wanted to store data offsite and trust computation done by different, separate entities, it created a need for verifiability or proofs of correctness. But these proofs had to be succinct because, by definition, the devices needing the proofs were small and probably not all that powerful (hence the need for cloud computing). Professor Kalai’s Succinct Non-interactive ARGuments, or SNARGs, paved the way for faster, more reliable transactions and have been used to verify transactions and computations in various technologies such as Ethereum’s blockchain.
The second trend shaping Professor Kalai’s research is the emerging presence of quantum computers which, though exciting, threaten to break basically every cryptography assumption. “If you have an adversary that has a quantum computer, most of cryptography goes away.” This has created a push in the community to upgrade cryptography for a post-quantum setting, a challenge Professor Kalai’s group is actively working on. There’s also a related challenge in quantum, which is verifying the correctness of quantum computation with classical computing methods. While scientists might have access to quantum computers now, the computers are expensive to run with unclear reliability. There’s an important need to know if the answer a quantum computer provides is correct, which is where cryptography can come in.
Finally, the elephant in the room for cryptography—as with most areas of computer science—is AI. The explosion of AI has created a host of new challenges which cryptographers are uniquely suited to address. “The question is: how do you check that the computation [AI models] do is correct? We as a community should answer that because we’ve been thinking about a very similar question for many years in cloud computing.” But despite the similarity on the surface, “when you dig a little deeper, you notice the setting is actually quite different.” For example, when someone uses cloud computing to delegate computation, the person or programmer doing the delegation knows what they want to compute. In AI, Professor Kalai explains, “I don't know what the input is, and I don't know how the AI should compute it. I just want an answer.” This means that Professor Kalai and her group have to explore different techniques than they’ve used in the past.
Generally, Professor Kalai’s approach is shaped by “what the world throws at us.” Cryptography might be theoretical in nature, but it is molded by the challenges presented to computer scientists. When approaching these problems, Professor Kalai says, “we try to use our mathematical knowledge to solve them.”
LOOKING AHEAD: AI, STUDENTS, AND BROADER THINKING
In addition to the challenges it presents in cryptography, the AI revolution also makes it very difficult to predict what’s coming next. With big data and quantum, Professor Kalai was able to imagine what the future might hold. But now she says, “I have literally no idea what the field will look like.” It’s an exciting question when one considers how much AI models might be able to advance technology, potentially solving problems that Professor Kalai herself can’t address. But it’s also concerning for her as both a researcher and a parent. Speaking of her three children—two of whom are interested in computer science—she wonders, “What should I advise them to study?” As AI continues to improve and affect nearly every area of life, the answer isn’t clear.
In the short term, though, Professor Kalai thinks it is the role of cryptographers to “ensure the safety of these AI models.” She would love to see more industry leaders thinking of cryptography as a way to address a widespread array of challenges and questions. “Any place where you need adversarial thinking, any place where there may be fault and you want things to be robust, that’s where cryptography can come in. Cryptography can do magic that is otherwise impossible.”
Whatever the future may hold, Professor Kalai is inspired by the CSAIL community, particularly the “really amazing students we have here. MIT students are just out-of-this-world remarkable.” Working with her research group and community of cryptographers, both at MIT and beyond, Professor Kalai continues to push the frontier of cryptography—one proof, one problem, and one breakthrough at a time.
Learn more about Professor Kalai on her CSAIL Page.