In an effort to meet the challenges of an academic year defined substantially by COVID-19 restrictions, Princeton’s electrical engineering department has provided a smartphone as a hands-on lab tool to every student in a course focused on the security of computers and smartphones.

The course, ELE 472 "Architectures for Secure Computer and Smartphones," is taught by Ruby Lee, the Forest G. Hamrick Professor of Engineering and a professor of electrical engineering. Lee is a leading researcher in computer architecture, hardware security and multimedia who spent nearly 20 years designing computers for Hewlett-Packard and was recently inducted into the American Academy of Arts and Sciences.

Like all Princeton classes this semester, ELE-472 is being taught virtually, with students using Zoom to attend the course’s twice-weekly lectures. The focus of the course is the design of secure processors, caches and systems for computers and smartphones. The course combines security concepts and computer architecture and ranges over an array of topics, including hardware-enhanced secure execution environments, solving security problems using machine/deep learning, smartphone security architecture, using smartphone sensors and deep learning to thwart imposters, designing secure caches to defeat side-channel information leakage, and understanding the recent "speculative execution attacks" on all microprocessors and their potential hardware defenses.

Lee knew virtual teaching this year would be difficult, especially for a diverse class of undergraduate and graduate students with varied backgrounds, a few of whom are in different time zones and as far away as the UK and China. But she took the circumstances as both a challenge and an opportunity to encourage creative learning.

“I thought about how we could make the learning experience in a virtual class setting not only as good as in a physical class, but perhaps even better in some ways,” she said.

Lee wanted students to experience working directly with some of the more unique features of a smartphone, like the built-in sensors, GPS, video or graphics functions, to improve smartphone security – and even incorporate cutting-edge deep learning techniques at the same time.  Normally, this would already be an ambitious project, but with students sequestered in their various living situations and unable to attend a “hands-on” lab, this aspect of the class was especially challenging.

So Lee hit upon a novel, “outside-the-box” solution.

“I explored the idea of getting a smartphone for every student, and amazingly, we managed to make it work,” Lee said.

The department chair, Sharad Malik, was very helpful in making funds available, and the department purchasing coordinator, Kate Furda, placed order for 24 Samsung smartphones to be sent directly to each student. A teaching assistant, Guangyuan Hu, helped select mid-range smartphones that had the advanced features Lee needed at a good price, and another T.A., Zecheng He, provided deep learning code known as "long short-term memory" for students to use.

To many of the students, getting a smartphone for the duration of the semester was a pleasant surprise.

“I was surprised by how smooth the process was to get the phone,” said Samuel Breckenridge, a senior majoring in electrical engineering. “I received my smartphone within a week and there was no issue with it.”

“It’s been a challenge how we [as students] can partake in any sort of lab work,” added Breckenridge. “So I think having the smartphones has been helpful in terms of allowing us the opportunity of working with something ‘hands-on.’”

Securing phones for each student is one way the department has eased some of the stress many students are feeling as a result of this year’s challenges. Lee also used class blogs, Zoom breakout rooms and polls to encourage student interaction in a virtual class environment.

“It’s a very strange time,” Lee said, “and some students feel a lot of anxiety. We on the teaching side are doing everything we can to make the students more comfortable and the class more stimulating. In the case of the smartphones, the students can still do hands-on labs and projects, with some teamwork.”   

Sophia Yoo, a graduate student in electrical engineering, concurred. “Zoom classes have not been easy,” she said, “but it’s neat to see Professor Lee and the other professors work hard to try to make it the best experience possible. Professor Lee is really trying to cultivate a sense of community in class.”