Skip to Content

Flawless Vote Counts

Cryptography lets voters verify ballots.
August 19, 2008

Since the 2000 election debacle, optical scanners have become the most common U.S. voting technology. Voters fill in a bubble next to a candidate’s name on a paper ballot and feed it into the scanner. The scanners tally votes automatically, saving time, but they also leave a paper trail that can be hand audited.

Even optical scanners can misread stray marks, however, and any voting machine can be tampered with after the fact. But a cryptographic system developed under the leadership of electronic-cash pioneer David Chaum can guarantee that every vote cast using an optical scanner is correctly recorded.

In the voting booth, instead of filling in a bubble in pencil, the voter uses a special pen to reveal a code printed inside the bubble in invisible ink. Later, the voter can enter the ballot’s serial number on an election website, which looks up the ballot and displays the associated code. If the code matches the one exposed in the booth, the vote was correctly tallied. But because the codes are never publicly correlated with candidates’ names, the voter’s privacy is maintained–and there’s no evidence to give to would-be vote buyers.

Until now, it’s been easy to dismiss cryptographic voting systems as academic exercises, but the fact that the new system is designed to work with optical scanning gives Chaum hope that it will catch on. “We’re ready,” he says. “There’s no risk. If you add it on, it doesn’t interfere with what you had, and if there’s a problem with it, you can just ignore it.”

Tamper-proof tally: A new cryptographic system can guarantee that votes cast using optical scanners are counted correctly. (1) The voter uses a decoder pen to expose a unique, randomly generated code printed in invisible ink next to a candidate’s name. (2) The voter writes the code on a detachable receipt marked with the ballot’s serial number. (3) An ordinary optical scanner reads the ballot, just as it would one marked in pencil. (4) At home, the voter enters the ballot’s serial number on an election website. If the site pulls up the corresponding code, the vote was recorded accurately.
Credit:
Brown Bird Design

Chart source: Election Data Services

Keep Reading

Most Popular

10 Breakthrough Technologies 2024

Every year, we look for promising technologies poised to have a real impact on the world. Here are the advances that we think matter most right now.

Scientists are finding signals of long covid in blood. They could lead to new treatments.

Faults in a certain part of the immune system might be at the root of some long covid cases, new research suggests.

AI for everything: 10 Breakthrough Technologies 2024

Generative AI tools like ChatGPT reached mass adoption in record time, and reset the course of an entire industry.

What’s next for AI in 2024

Our writers look at the four hot trends to watch out for this year

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.