David Freeman

David Freeman

Anti-Abuse Research Scientist & Engineering Leader
Principal, Delphi Research
dfreeman @ delphiresear . ch
LinkedIn Profile CV (PDF)
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I help platforms detect and stop fraud and abuse, turning escalating risks and chaotic organizations into managed programs.

About Me

I am a data scientist / software engineer / security researcher with both hands-on and leadership experience in every step of the security lifecycle: threat assessment, system design, model building, production deployment, and continuous iteration.

I spent 14 years building and leading teams at Meta and LinkedIn to address problems such as fake & compromised accounts; impersonation & identity verification; fraud, spam, & phishing; user-data scraping; and measurement of all of the above.

I have published 27 research papers in cryptography and computer security, been cited more than 5,000 times, and chaired international security workshops including Usenix Enigma, CCS AISec, and Fighting Abuse@Scale.

I currently live in the San Francisco Bay Area with my wife, two daughters, and five black cats.*

Consulting

I work with teams to understand their abuse risks and address the highest-priority vulnerabilities, whether or not there is an active attack. Typical engagements consist of one or more of the following:

  • Quantify the problem: Set up logging and data management for full-system visibility. Measure attacker prevalence and intervention effectiveness.
  • Build the detection system: Collect signals, analyze telemetry, and engineer features. Train, validate, and deploy models.
  • Harden the surface: Reduce scraping and data-leakage exposure, close fake-account and account-compromise vectors, and balance security with user experience.
  • Support the team: Build process and automation that responds to highly adaptive adversaries. Set up structures for hiring and retaining security engineering talent.

Specialties: Anti-Scraping • Authentication • Fake Accounts • Scams • Risk Quantification • Measuring Detection Effectiveness • Building Security Teams

Example engagements:

Contact me to discuss your project!

Resources

Here are some presentations that give an overview of my work:

  • My KISA 2026 talk looks at how AI will change the landscape of fighting internet abuse at scale.
  • My Enigma 2020 talk describes good and bad approaches to measuring abuse on the internet.
  • My ScAINet 2018 talk presents some of the challenges in using machine learning for security in the real world.
  • My Enigma 2016 talk shows some approaches to protecting accounts from being taken over.
  • My Strata 2015 talk gives an overview of the kinds of anti-abuse systems I work on.

In addition, my book on Machine Learning and Security contains everything I knew about the topic (as of 2018).

Academic Background

I received my Ph.D. in Mathematics from the University of California, Berkeley. My Ph.D. advisors were Ken Ribet (UC Berkeley) and Ed Schaefer (Santa Clara University). Following my Ph.D., I was an NSF postdoctoral fellow at CWI, Amsterdam and Universiteit Leiden under the supervision of Ronald Cramer. I then spent three years as a postdoctoral scholar at Stanford under the supervision of Dan Boneh.

My thesis and postdoctoral research focused on cryptographic applications of number theory and arithmetic geometry. Projects included elliptic and hyperelliptic curve cryptography, pairing-based systems, and post-quantum cryptography.

My undergraduate degree is from Harvard (Chemistry and Physics and Mathematics) and I have a master's degree from Cambridge (Part III Maths).

* Technically four black cats and one gray cat, but we call the gray one "light black."

Books

Machine Learning and Security: Protecting Systems with Data and Algorithms Clarence Chio and David Freeman O'Reilly Media, 2018

Research at Meta

Research at LinkedIn

Research at Stanford and CWI

Research at UC Berkeley

Undergraduate Research

Other Papers

Anti-Abuse

Cryptography

Program Committee & Conference Service

Teaching

Since 2023 I've coached the Mathcounts team at Bullis Charter School in Los Altos, CA.

In Fall 2011 I taught Elliptic Curves in Cryptography (CS 259C/Math 250) at Stanford. Course web page.

In Fall 2007 I was a Graduate Student Instructor for Math 16a at Berkeley, taught by Jack Wagoner. Section web page.

In Fall 2005 I was a Graduate Student Instructor for Math 1a at Berkeley, taught by Vaughan Jones. Section web page.

Other Activities

Contact Dr. Freeman

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