Tampering with Special Purpose Trusted Computing Devices: A Case Study in Optical Scan E-Voting

Posted: December 10th, 2007 | Author: | Filed under: Other Publications | Tags: , , , , , ,

Tampering with Special Purpose Trusted Computing Devices: A Case Study in Optical Scan E-Voting
Aggelos Kiayias, Laurent Michel, Alexander Russell, Narasimha Shashidhar, Andrew See, Alexander Shvartsman and Seda Davtyan
In Proceedings of the Twenty-Third Annual Computer Security Applications Conference (ACSAC 2007)
December 10-14, 2007, Miami, Florida www.acsac.org/

Abstract
Special purpose trusted computing devices are currently being deployed to offer many services for which the general purpose computing paradigm is unsuitable. The nature of the services offered by many of these devices demand high security and reliability, as well as low cost and low power consumption. Electronic Voting machines is a canonical example of this phenomenon. With electronic voting machines currently being used in much of the United States and several other countries, there is a strong need for thorough security evaluation of these devices and the procedures in place for their use. In this work, we first put forth a general framework for special purpose trusted computing devices. We then focus on Optical Scan (OS) electronic voting technology as a specific instance of this framework. OS terminals are a popular e-voting technology with the decided advantage of a user-verified paper trail: the ballot sheets themselves. Still election results are based on machine generated totals as well as machine-generated audit reports to validate the voting process.

In this paper we present a security assessment of the Diebold AccuVote Optical Scan voting terminal (AV-OS), a popular OS terminal currently in wide deployment anticipating the 2008 Presidential elections. The assessment is developed using exclusively reverse-engineering, without any technical specifications provided by the machine suppliers. We demonstrate a number of security issues that relate to the machine’s proprietary language, called AccuBasic, that is used for reporting election results. While this language is thought to be benign, especially given that it is essentially sandboxed by the firmware to have only read access, we demonstrate that it is powerful enough to (i) strengthen known attacks against the AV-OS so that they become undetectable prior to elections (and thus significantly increasing their magnitude) or, (ii) to conditionally bias the election results to reach a desired outcome. Given the discovered vulnerabilities and attacks we proceed to discuss how random audits can be used to validate with high confidence that a procedure carried out by special purpose devices such as the AV-OS has not been manipulated. We end with a set of recommendations for the design and safe-use of OS voting systems.

Download full paper:: acsac07-voter.pdf


An Internet Voting System Supporting User Privacy

Posted: December 15th, 2006 | Author: | Filed under: Other Publications | Tags: , , , , ,

An Internet Voting System Supporting User Privacy
Aggelos Kiayias, Michael Korman and David Walluck
22nd Annual Computer Security Applications Conference (ACSAC 2006), IEEE Computer Society 2006, pp. 165-174.
December 11-15, 2006, Miami Beach, Florida, USA www.acsac.org/

Abstract
This work introduces the ADDER system , an Internetbased, free and open source electronic voting system which employs strong cryptography. Our system is a fully functional e-voting platform and enjoys a number of security properties such as robustness, trust distribution, ballot privacy, auditability and verifiability. It can readily implement and carry out various voting procedures in parallel and can be used for small scale boardroom/department-wide voting as well as largescale elections. In addition, ADDER employs a flexible voting scheme which allows the system to carry out procedures such as surveys or other data collection activities. ADDER offers a unique opportunity to study cryptographic voting protocols from a systems perspective and to explore the security and usability of electronic voting systems.