Many people have discovered the convenience of shopping on-line. Now, thanks to three Brown mathematics professors, they may soon be able to do the same thing using their cell phones or hand-held organizers. Joseph Silverman ’77, Jeffrey Hoffstein, and Jill Pipher have designed a public-key encryption system that is much smaller and up to 200 times faster than conventional methods for on-line shopping and that should make possible the secure transfer of data from just about anywhere.

The idea for the encryption system, says Silverman, originated with Hoffstein. After returning from a semester teaching at UC Berkeley, Hoffstein recruited cryptography specialist Pipher and Silverman, whose specialty is number theory, to design a cryptographic system that used very little memory but was smart enough to ensure security. “It was something we worked on in our spare time,” Silverman says. “We thought, ‘There’s got to be a better way to do these things.’ You could explain most of the mathematics used in cryptography to a bright twelfth grader.”

But what at first seemed like a simple task soon became complicated. “Analyzing why something is or isn’t secure,” Silverman says, “does use some sophisticated math.” But the team stuck to it, and eventually they devised a system that they were certain was foolproof. Now the three math professors — when they aren’t teaching classes or grading exams — are co-vice presidents and founders of NTRU, a private corporation that recently received $11 million in capital from Greylock Management and Sony.