Fwd: [security-lunch] May 27 | Ryan Cottone on "Acumen: A Platform for Encrypted and Accountable Collaborative Editing"

[Alan Karp]

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Alan Karp

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From: Michael Leo Paper via security-lunch <securit...@lists.stanford.edu>
Date: Mon, May 25, 2026 at 11:31 AM
Subject: [security-lunch] May 27 | Ryan Cottone on "Acumen: A Platform for Encrypted and Accountable Collaborative Editing"
To: securit...@lists.stanford.edu <securit...@lists.stanford.edu>

Security Lunch 🌱 Ed. — Wednesday,  May 27th, 2026, 12:00 pm @ CoDa E160

Acumen: A Platform for Encrypted and Accountable Collaborative Editing

Ryan Cottone

Can't make it in person? Join us on zoom.

See our past & upcoming events on our website! 

Abstract: 

Modern-day collaborative editing tools must reconcile a tension between user privacy and collaboration: encrypting user data prevents an application server from processing user edits. We present Acumen, a cryptographic system for real-time collaborative applications based on conflict-free replicated data types (CRDTs). Acumen is the first system to provide strong snapshot consistency, enabling untrusted users to create verifiable document snapshots used to invite new collaborators. Acumen also provides confidentiality, integrity, fork-causal consistency, and ensures that invited users do not learn the previous edit history of the document. We achieve these properties through the use of cryptographic accumulators and a novel secure garbage collection mechanism. Alongside its stronger security guarantees, our evaluation shows that Acumen supports throughput orders of magnitude greater than the state-of-the-art secure collaborative editor.

Bio:

Ryan Cottone is a first year Computer Science PhD student at Stanford University. His research focuses on applied cryptography with an emphasis on secure computation. You can find out more at his website: https://ryancottone.com

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