Author ORCID Identifier

0009-0006-9154-7205

Document Type

Dissertation

Date of Award

5-31-2026

Degree Name

Doctor of Philosophy in Computing Sciences - (Ph.D.)

Department

Computer Science

First Advisor

Chase Qishi Wu

Second Advisor

Qiang Tang

Third Advisor

Vincent Oria

Fourth Advisor

Cristian Borcea

Fifth Advisor

Shantanu Sharma

Abstract

Encypted messaging has become more and more prevalent as time moves on, and its benefits in assuring privacy cannot be overstated, but it also brings along with it concerns on how to moderate platforms where all messages are hidden. Message Franking, followed by Traceback systems, addressed these concerns by allowing the sender of a message to be proven when reported, even for forwarded messages in the case of Traceback, however these systems damage the privacy guarantees that originally motivated encrypted messaging to begin with.

In practice, even without those concerns encrypted messaging alone is not enough to prevent the most unsettling possibilities of platforms or governments abusing metadata collected on messaging activity, but Anonymous Messaging can solve both issues, as long as it can be moderated without compromising that anonymity.

An Anonymous Accountability system is necessary to deal with potential harassment, viral misinformation, and other abuses by malicious users, while still maintaining as much privacy and anonymity as possible. This work begins with a fast symmetric cryptography approach to tracing viral messages to their original source without de-anonymizing the users along the forwarding path, and then moves on to make use of malleable zero knowledge proofs and anonymous blocklisting techniques to create an Anonymous Accountability system that allows banning the original sender of a forwarded (potentially viral) message without ever learning their identity, achieving perfect anonymity for all users involved. The message that the user was banned for saying is known, but who they are is not; through this, the system also creates a possibility of publicly auditing the moderation actions of the platform, allowing users to hold the platform accountable for moderation actions that go against their stated policies.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.