Joshua A. Kroll

Computer Scientist, Hacker, Recovering Physicist

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Welcome!

I'm a computer scientist and researcher interested in the governance of automated decision-making systems, especially those built with machine learning. I'm a Postdoctoral Research Scholar at UC Berkeley's School of Information, working with Deirdre Mulligan. I received a PhD in Computer Science in the Security Group at Princeton University, which is an important part of Computer Science history. My dissertation on Accountable Algorithms was advised by Edward W. Felten and supported by the Center for Information Technology Policy where I studied many topics in security, privacy, and how technology informs policy decisions. For a time, I was also advised by Andrew Appel and worked on memory safety and software security.

The following facts about me may or may not interest you: I received the National Science Foundation Graduate Research Fellowship in 2011. For many years, I traveled to Boston each fall to perform Improbable feats of engineering. I got married to my secret high-school crush in 2012.

Deeper in the past, I attended a small college near Boston, MA where I spent a lot of time playing with technology and making it accessible to the masses. Prior to that, I grew up in Monterey, CA where I can recommend a good dentist. It was there that I got my start as a Computer Scientist, and experienced the inner workings of government.

I do occasional consulting work on policy and practical issues in algorithmic accountability. If you'd like to know more, please contact me.

I don't always blog, but when I do, you can find my ramblings linked from the publications page. You might also find me making birdcalls online from time to time. You can also find a more formal bio and headshot here.

Bio & Headshot

Joshua A. Kroll is a computer scientist studying the relationship between governance, public policy, and computer systems. Currently, Joshua is a Postdoctoral Research Scholar at the School of Information at the University of California at Berkeley. His research focuses on how technology fits within a human-driven, normative context and how it satisfies goals driven by ideals such as fairness, accountability, transparency, and ethics. He is most interested in the governance of automated decision-making systems, especially those using machine learning. His paper "Accountable Algorithms" in the University of Pennsylvania Law Review received the Future of Privacy Forum's Privacy Papers for Policymakers Award in 2017.

Joshua's previous work spans accountable algorithms, cryptography, software security, formal methods, Bitcoin, and the technical aspects of cybersecurity policy. He also spent two years working on cryptography and internet security at the web performance and security company Cloudflare. Joshua holds a PhD in computer science from Princeton University, where he received the National Science Foundation Graduate Research Fellowship in 2011.

Headshots: small, large

Research

I'm interested in a broad swath of topics in and outside of security (computer and otherwise), privacy (online and otherwise), and related questions in public policy. I'm also strongly interested in cryptography. My dissertation research was on Accountable Algorithms, and tools for bridging technical assurances with human oversight.

For more information, you should contact me.

Publications

Peer-reviewed Publications

  • Jacobs, A. Z., J. A. Kroll, and A. Smart. “Unsafe at Any AUC: Unlearned Lessons from Sociotechnical Disasters for Responsible AI”. (In Submission)
  • Jatho, E. W., L. O. Mailloux, E. D. Williams, P. McClure, and J. A. Kroll. “Concrete Safety for ML Problems: Systems Safety for ML Development and Assessment”. (In Submission)
  • Rismani, S., Shelby, R., Smart, A., Jatho, E., Kroll, J., Moon, A. and Rostamzadeh, N., 2023, April. “From plane crashes to algorithmic harm: applicability of safety engineering frameworks for responsible ML”. In Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems. [PDF]
  • Jatho, E. W., L. O. Mailloux, S. Rismani, E. D. Williams, and J. A. Kroll. “System Safety Engineering for Social and Ethical ML Risks: A Case Study”. NeurIPS Workshop on Machine Learning Safety, December 2022. (Best System Safety Paper) [PDF]
  • Kroll, J. A., “ACM TechBrief: Facial Recognition”, ACM TechBriefs, Issue 2, Feb. 2022. [PDF]
  • Carter, T., J. A. Kroll, and J. B. Michael. “Lessons Learned Applying the NIST Privacy Framework”. IEEE IT Professional. Vol. 23, Iss. 4 (2021). [Available Online via Government Purpose Rights]
  • Kroll, J. A., J. B. Michael, and D. B. Thaw. “Enhancing Cybersecurity via Artificial Intelligence: Risks, Rewards, and Frameworks”. IEEE Computer, Volume 54, Issue 6. June, 2021. [Online]
  • Kroll, J. A., “Outlining Traceability: A Principle for Operationalizing Accountability in Computing Systems”, Conference on Fairness, Accountability, and Transparency, March 2021. [PDF]
  • Mulligan, D., J. A. Kroll, N. Kohli, and R. Wong, “This Thing Called Fairness: Disciplinary Confusion Realizing a Value in Technology”, Computer Supported Cooperative Work (CSCW’19), November 2019. [PDF]
  • Luckie, M., R. Beverly, R. Koga, K. Keys, J. A. Kroll, and k. claffy, “Network Hygiene, Incentives, and Regulation: Deployment of Source Address Validation in the Internet”, ACM Conference on Computer and Communications Security (CCS’19), November 2019. [PDF]
  • Kroll, J. A., N. Kohli, and P. Laskowski, “Privacy in Polystores: A Data Management Research Agenda”, VLDB Workshop on Polystore Systems (POLY’19), August 2019. [PDF]
  • Bruening, P. and J. A. Kroll, “Considering Transparency: AI, Data Science and the GDPR.” Computers, Privacy, and Data Protection, January 2019.
  • Kroll, J. A. “The Fallacy of Inscrutability.” Philosophical Transactions of the Royal Society A Vol. 376 No. 2133, 2018. [Online]
  • Kroll, J. A. “Data Science Data Governance.” IEEE Security & Privacy, Volume 16, Issue 6. November 2018. [PDF]
  • Desai, D. and J. A. Kroll. "Trust But Verify: A Guide to Algorithms and the Law", Harvard Journal of Law and Technology. Vol 31, Issue 1. 2018. [PDF]
  • Kroll, J. A., Huey, J., Baroas, S., Felten, E. W., Reidenberg, J. R., Robinson, D. G., and Yu, H. "Accountable Algorithms" University of Pennsylvania Law Review, Vol. 165, Issue 3. 2017. [SSRN] [PDF]2016 Future of Privacy Forum Privacy Papers for Policymakers Award
  • Bonneau, J., Miller, A., Clark, J., Narayanan, A., Kroll, J., and Felten, E., "SoK: Bitcoin and second-generation cryptocurrencies", 36th IEEE Symposium on Security and Privacy, San Jose, CA, May 18-20 [PDF]
  • Kroll, J., Felten, E., and Haldermann, J. A., "Efficiently Auditing Multi-Level Elections", 6th International Conference on Electronic Voting (EVOTE 2014), Lochau, Austria, October 28-31, 2014 [PDF]
  • Edmundsen, A., Simpson, A.K., Kroll, J., and Felten, E., "Security Audit of Safeplug 'Tor in a Box'", 4th USENIX Workshop on Free and Open Communication on the Internet (FOCI 2014), San Diego, CA, August 18, 2014.[PDF]
  • Clark, J., Bonneau, J., Felten, E., Kroll, J., Miller, A., and Narayanan, A., "On Decentralizing Prediction Markets and Order Books", Thirteenth Workshop on the Economics of Information Security (WEIS 2014), State College, PA, June 23-24 2014. [PDF]
  • Kroll, J., Stewart, J., and Appel, A. "Portable Software Fault Isolation". Computer Security Foundations, 2014 (CSF 2014), Vienna, Austria, July 19-22 2014. [PDF]
  • Kroll, J., Felten, E., and Boneh, D. "Secure Protocols for Accountable Warrant Execution". Preprint. [PDF]
  • Goldfeder, S., Bonneau, J., Felten, E., Narayanan, A., "Securing Bitcoin Wallets with Threshhold Signatures". Preprint. [PDF]
  • Bonneau, J., Narayanan, A., Miller, A., Clark, J., and Kroll, J. "Mixcoin: Anonymity for Bitcoin with accountable mixes," Financial Cryptography, 2014 (FC 2014), Bridgetown, Barbados, March 3-7 2014. [PDF (full version)]
  • Kroll, J., Davey, I., and Felten, E., "The Economics of Bitcoin Mining, or Bitcoin in the Presence of Adversaries", The Twelfth Workshop on the Economics of Information Security (WEIS 2013), Washington, DC, June 10-11 2013. [PDF]
  • Kroll, J. and D. Dean, “BakerSFIeld: Bringing Software Fault Isolation to the x64,” SRI Computer Science Laboratory Technical Report, 2009. [PDF]
  • Martell, C. and J. Kroll, “Corpus-Based Gesture Analysis: An extension of the FORM dataset for the automatic detection of phases in a gesture”, Int. J. Semantic Computing, 1(4): 521-536 (2007). [PDF] [Journal Page]
  • Martell, C. and J. Kroll, “Using FORM to Predict Phase Labels”, Proceedings of the Language Resources and Evaluation Conference, Workshop on Multimodal Corpora, Genoa, Italy, 27 May 2006. [PDF]

Dissertation

  • Kroll, J. Accountable Algorithms (Doctoral Dissertation). Princeton University. 2015. [Library, PDF]

Public Policy Publications and Regulatory Filings

  • Barocas, S., Felten, E., Huey, J., Kroll, J., and Narayanan, A. "Big Data and Consumer Privacy in the Internet Economy". Comment to the NTIA Big Data Request for Comments, 79 Fed. Reg. 32714. August 5, 2014. [PDF]

Other Publications

  • Technical Reports


    • Kroll, J. A. and V. Berzins, “Understanding, Assessing, and Mitigating Safety Risks in Artificial Intelligence Systems”. Naval Postgraduate School Technical Report, NPS-CS-22-003. December, 2022. [Report Page]

  • Popular Articles


    • Jatho, E and J. A. Kroll, “Artificial Intelligence: Too Fragile to Fight”, Proceedings of the US Naval Institute, Feb. 2022. First Prize, USNI Information Warfare Essay Contest. [Available Online by Government Purpose Rights]
    • Felten, E., and Kroll, J. "Heartbleed Shows Government Must Lead on Internet Security". Scientific American, 16 April 2014. [article]
    • Kroll, J. "The Cyber Conundrum". The American Prospect. 1 June 2015. [article]
    • Kroll, J. "The Cyber Conundrum: A Security Update". The American Prospect Online. 3 June 2015. [article]

  • Opinion Pieces, Blog Posts, and Essays


    • Kroll, J. A.,“Responsible AI is a Management Problem, Not a Purchase”, The Regulatory Review, 4 July, 2022. [Online]
    • Kroll, J. A., “Why AI is Just Automation”, Brookings Institution Report (AI and Bias series), 14 July, 2021. Cited in the 2023 Economic Report of the President. [Online]
    • Kroll, J. "Accountable Algorithms". Balkinization. 31 March 2016. [post]
    • Kroll, J. "Accountable Algorithms (A Provocation)". LSE Media Policy Project Blog. 10 February 2016. [post]
    • Kroll, J. "The Debian OpenSSL Bug: Backdoor or Security Accident?¯¯". Freedom To Tinker. 20 September 2013. [post]
    • Kroll, J. "Is the NSA Keeping Your Encrypted Traffic Forever?". Freedom To Tinker. 13 September 2013. [post]
    • Kroll, J. "Which States have the Highest Risk of an E-Voting Meltdown?". Freedom To Tinker. 27 September 2012. [post]
    • Kroll, J. "The Next Step Towards an Open Internet". Freedom To Tinker. 1 April 2016. [post]

    Presentations

    • Kroll, J. and S. Roosa. "The Algorithm Made Me Do It: Predictive Power, Ethics and the Law in the Age of Machine Learning, Artificial Intelligence, and Mathematical Perplexity". Highmark Health All-Hands Privacy Workshop, Pittsburgh, PA, January 11, 2017. (Invited).
    • Kroll, J. "Accountable Algorithms". Workshop on Data and Algorithmic Transparency, NYU Law School. 19 November 2016. (Selected by Peer Review)
    • Kroll, J. "Accountable Algorithms". SRI International Computer Science Lab Formal Topics Seminar, 19 October 2016. (Invited)
    • Kroll, J. Powell, A. and Vis, F., "Algorithmic Accountability". Big Boulder Conference, June 24, 2016. (Invited) [event]
    • Kroll, J. "Accountable Algorithms". "Unlocking the Black Box" Conference, Internet & Society Project, Yale Law School, 1 April 2016. (Competitive Selection) [event]
    • Kroll, J. "Accountable Algorithms". "Algorithmic Power and Accountability in Black-Box Platforms" Workshop, Media Policy Project, London School of Economics, 25 January 2016. (Invited) [event]
    • Kroll, J. "Big Data, Fairness, and Nondiscrimination". New Jersey Attorney General's Advocacy Institue In-Service Training, August 7, 2014.
    • Kroll, J. "Accountable Algorithms". Princeton Joint ACM/IEEE Computer Society Chapters Meeting, 17 April 2014 [event]
    • Kroll, J. "The Economics of Bitcoin Mining, or Bitcoin in the Presence of Adversaries". Princeton University Center for Information Technology Policy Luncheon Series, 14 November 2013 [event] [video]
    • Barber, G. and Kroll, J. "Drones: Not Just for Military Use". New Jersey Attorney General's Advocacy Institute In-Service Training, August 8, 2013 (CLE credit course).
    • Felten, E. and Kroll, J. "The State of Electronic Voting". Princeton University Center for Information Technology Policy Luncheon Series, 18 October 2012. [event] [video]
    • Kroll, J. "Seeing Under Sea: Applications of Computer Vision in Underwater Video," Plenary Address, Harvard Undergraduate Research Symposium, Nov. 2006 (Accepted by faculty review; top 3 of 140 papers).

    Press

    • "No one in control: The algorithms that run our lives", New Scientist, February 4, 2015.
    • "Bitcoin Is Flawed, But It Will Still Take Over the World", WIRED, November 25, 2013.
    • "The Future of Bitcoin: Corporate Mines and Network Peering?", Data Center Knowledge, January 24, 2014.
    • "Academics Spy Weaknesses in Bitcoin's Foundations", MIT Technology Review, March 24, 2014.
    • "Tor Weekly News", September 24, 2014.
    • "Safeplug Security Analysis", Schneier on Security, September 10, 2014.
    • "With This Tiny Box, You Can Anonymize Everything You Do Online", WIRED, October 13, 2014.

Teaching

I sincerely enjoy teaching and am always looking for chances to do more of it. I've been fortunate to have many opportunities to be a teacher, a tutor, a docent, a guest speaker, and many other things. Please contact me if you'd like to know more.

I have taught the following university-level courses:

  • Princeton University, Department of Computer Science. Assistant in Instruction, Computer Science 226: Algorithms and Data Structures. Professor Robert Sedgewick, Instructor. Spring 2011.
  • Princeton University, Department of Computer Science. Assistant in Instruction, Computer Science 432: Information Security. Professor Edward Felten, Instructor. Fall 2010.
  • Harvard University, Department of Mathematics. Head Course Assistant (of 6), Mathematics 23a/b: Linear Algebra and Real Analysis I/II. Dr. Paul G. Bamberg, Instructor. 2006-2007.

Please contact me if you have a specific interest and we can talk.

CV

My curriculum vitae. I cannot guarantee that the one on this website is up-to-date.

For a current copy of my CV, it would be best to contact me.

Contact Me

I am most easily contacted via E-mail at .

If you're contacting me regarding consulting work, please write instead to .

If you prefer to send mail of the physical variety, please send it to me thusly:

Joshua Kroll
PO Box 2419
San Anselmo, CA 94979