Rick Carback’s Blog

This article is cross-posted from the punchscan blog. Leave your comments over there.

Both part 1 and 2 dealt with interface problems between the voter and a paper ballot, machine, or computer that records her vote. For this last segment, Surveillance, we discuss the ways the voter can be watched to determine her choices. Because the attacker or a device must be present to carry out these attacks, they are generally considered more expensive to carry out than what we have discussed so far.

Using the same strategy as seen in the previous segment, we will start with simple examples of this attack, move on to more elaborate examples, and end our discussion with how you could defend against these attacks. Again, as we’ve already seen, different flavors of these attacks may or may not require voter cooperation to work.

Simple Surveillance

The simplest paper ballot scenario is the following: the local union boss sits in the polling place. You flash your ballot to him as you take it from the booth to the ballot box or scanner. He checks your name off on his list.

Another, that works for DREs as well, is to take a cell phone picture or video of your ballot just before or as you are casting it. If the DRE has an audio interface, you may also be able to hook up an audio recorder and record your vote casting experience on tape.

Another class is the “over the shoulder” attack. The voter or poll workers may or may not have to cooperate for it to work. In some cases you may be able to succeed at a significant distance.

Hacking the Machine

The optical scanner or computer (or even lever machine), by definition, records voter choices. It could be modified to keep a serial record this input. The attacker can record the serialization to each voter by recording the order of who uses the machine, and retrieve the record after the election.

Because of the trail it would leave, this class of attacks is undesirable. However, our current testing practices and laws are such that this information might be public record, as seen in Ohio after the 2006 election.

Going High Tech

Mini wireless spy cameras sell for as low as $70, possibly lower. That is well within the range of affordability. In addition, the relative predictability of how polling places are set up means the cameras could be there days before the election begins. A bag or pen equipped with this technology would have no problem recording voter choices.

The camera does not have to be limited to the visible light spectrum. An infrared or other kind of camera might be much easier to hide. In some cases, your body might not be enough to block its vision.

It may not even need to be a camera. Sensors or microphones in the polling booth might be enough to correlate voter choices. You can recover typed text using audio, it’s not a huge jump to do it for voting.

TEMPEST Attacks

A TEMPEST attack is one which records electronic emanations that reveal information being processed by the computer. A dutch group created a great video showing how this works. Take a look:

My favorite TEMPEST hack, from what I have seen, is an MP3 player for CRT monitors. Just tune your AM radio and enjoy.

Defeating Surveillance

In general, it’s an arms race. As technology progresses and becomes ever more affordable, the situation gets worse. Unless you can strip each voter and scan for optical eye and other types of implants, election officials will eventually lose.

The strategy here should be to drive up costs and take precautions. Make machines that meet the TEMPEST standards. Go to each polling place and do a scan for wireless emissions. Look for cameras and sensors when you set up the polling place. Do not allow voters to take cell phone cameras or bags into the voting booth. As long as it is prohibitively expensive, the laws are harsh, and there is the threat of being caught, it is hopefully not worth it.

• Part 1: Pattern Voting
• Part 2: Identifying Marks