Robert J. Walls

147 Fuller Labs
Worcester, MA 01609

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Students!: I am currently looking for motivated and qualified students. If you are a WPI student, please send me an email or stop by. If you are outside of WPI, I invite you to apply and then contact me.

About Me

I am an assistant professor in the Department of Computer Science at Worcester Polytechnic Institute. My current interests focus on low-level systems security. In the Fall of 2016, I brought in security researchers from around to the area to participate in New England Security Day.

Previously, I was a postdoctoral scholar in Department of Electrical Engineering and Computer Science at The Pennsylvania State University working with Prof. Patrick McDaniel. Before that, I attended the School of Computer Science at the University of Massachusetts advised by Prof. Brian Levine. My research at UMass focused on providing law enforcement with novel techniques for investigating crimes. You can find my thoughts on the difference between forensics and security here.


I’ve had the opportunity to work on a number of interesting research projects during my career. Here is a summary of some of my efforts.

Embedded Security

The security of embedded systems lags well behind that of general-purpose machines. In large part, this difference is due to the lack of hardware primitives many security techniques depend upon, e.g., few embedded systems sport a memory management unit and thus most lack support for virtual memory.

Web Security and Privacy

Domain names have become the Internet’s de facto root of trust. In practice, they are also a root of insecurity as common security systems depend on the unfounded assumption that domain ownership remains constant; this leaves users vulnerable to exploitation when domain ownership changes. In our [Oakland 2016][oakland16] we find that many seemingly disparate security problems share a root cause in residual domain trust abuse.

Online advertising is one of those little annoyances that we all have to deal with. “Not so!” Said the plethora of ad blocking extensions promising to improve your browser experience. Not only do they block ads, they also claim to help preserve your privacy and protect you against the growing trend of malicious advertisements. In our IMC 2015 work my co-authors and I take a closer look at the most popular ad blocking software. We find that ad blockers are not quite what they appear to be.

Digital Forensics

Mobile phones contain evidence that is invaluable for criminal investigations. However, commercially-available forensic tools must be hand-tailored to each phone model. If no tools support the target phone, then extracting the phone’s information requires investigators to examine the stored data byte by byte. To address this problem, I’ve developed general algorithms and techniques for recovering information from phones even if the exact storage format is unknown or the data has been logically deleted.

DECODE is an inference engine that extracts meaningful information from raw byte streams. Read more about it here.

Liftr incorporates investigator feedback and relevance graphs to improve the results of inference engines like DEC0DE. Paper here.

Yapr parses the Yaffs File System commonly found on (older) Android phones. Yapr even has limited ability to reconstruct past versions of a file by leverage expired pages of flash memory.

Filtr implements the concept of block hash filtering using bloom filters. In short, Filtr will remove an repeated blocks of data in a raw byte stream. For flash-based devices, such as phones, Filtr often removes 50-90% of the raw data, saving precious time by limited the amount of data that needs to be examines. Read more about block hash filtering here.

Science of Security

Perhaps the most ambitious projects I’ve been involved with is the 10-year Cyber-Security Collaborative Research Alliance with the Army Research Laboratory, Penn State, Carnegie Mellon, UC Riverside, UC Davis, and Indiana University. The project’s mandate is to develop a new science of security. As part of this effort, I’ve worked on the foundation for representing operational and environmental knowledge—see my work on ontologies here—with the goal of reasoning about both current and future states to make optimal security decisions.

Improving the Process

Like all computer scientists, I am constantly on the lookout for tools or methods that will help me be more efficient in my work. Here are a few repositories that you may find helpful.

Latex Paper Template. Tired of wasting half an hour setting up your paper directory every time you start a new project? Try my paper template instead.

Slidify Tutorial. I am a big fan of presentations, R, and Markdown—Slidify beautifully combines all three. Check out my simple Slidify tutorial here.