Assistant Professor
Department of Computer Science

The path to Cornell has taken several interesting turns for Rafael Pass.

After graduating from Sweden’s Royal Institute of Technology with a degree in engineering physics, Rafael Pass went to work for JP Morgan Securities in Paris. Although not trained as a business analyst, Pass speaks several languages and spent two years at elite French schools, studying mathematics and computer science at the École Polytechnique and philosophical logic at the Sorbonne. In less than a year he was in London, working for PriceWaterhouseCoopers, and a year later, back in his native Sweden, co-founding a software company specializing in security solutions. 

While he enjoyed the world of high finance, Pass wanted to try theoretical research. “My dad was a mathematics teacher at the senior high school before he retired. He taught me some math when I was a kid,” he says. “Even then I think I had a philosophical interest in understanding how things work.” 

So he headed back to The Royal Institute, this time earning an M.S. in computer science. “I got into cryptography when I started my master’s,” he says. “I discovered I loved research and I loved the academic world.”

After completing his Ph.D. at MIT in just two years, Pass joined the faculty at Cornell, where he is looking forward to collaborating with fellow faculty. “I’ve been trying to get involved in the intersection of cryptography and game theory,” he says, “analyzing how strategic actors will work in different scenarios.”

Cryptography has been with us for millennia, used for most of that time as Caesar used it, to protect military communications. With the advent of the Internet, however, cryptography has broadened its scope tremendously. You probably depend on cryptographic protocols on a daily basis—to authenticate a message, in online auctions, or to protect your credit card number when shopping on the Web.

“Cryptography today is about how to communicate and compute in the presence of an adversary,” says Pass. “What are the limits of communication?”

One area that interests Pass is zero knowledge proofs—convincing someone that something is true without revealing anything else. An example he uses with students involves “Where’s Waldo.” How could you convince someone else that you know where Waldo is without revealing Waldo’s location? It might seem impossible, but there is a way.

While this example may seem trivial, the same principle is at work in trying to convince someone you have enough money in your account to purchase an item without revealing exactly how much money you have in that account. It illustrates why Pass is interested in a thorough understanding of what is and what is not knowledge.

Concurrency is another area of interest for Pass. The Chess Masters Dilemma is a classic example. A novice would have little hope of beating a chess master, but by playing two chess masters simultaneously, duplicating the moves of one against the other, even a newbie can beat a grand master.  

Applied to cryptographic protocols, such “man in the middle” attacks can break the security of protocols that otherwise seems impenetrable. “It is often the case that our intuition is wrong,” says Pass. “There are many magical things that people, a priori, thought not possible which are possible.”

Prof. Pass' Web page