Ballot Acrobatics: Altering Electronic Ballots using Internal PDF Scripting

Abstract

In recent decades, it has become increasingly common to transmit absentee ballots electronically as PDF files in American elections. Current PDF ballot policies provide certain voter groups, often military and overseas voters, with a more convenient alternative to the existing mail-based system of physical ballot transmission. This thesis offers an overview of the current role of PDF technology in voting procedures in the United States, and analyzes how the internal scripting capabilities of PDFs allow adversaries to manipulate PDF ballots and compromise election integrity. We conclude that, although they provide convenience and accessibility, PDF ballots as currently used in US elections jeopardize election security due to their vulnerability to scripting-based manipulation attacks. Future areas of research include analyzing the security of other data storage formats in the context of electronic ballots, investigating the security of electronic ballot transmission over networks, and developing new solutions for secure, accessible voting.