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

computation concept
computation concept

How AI is reinventing what computers are

Three key ways artificial intelligence is changing what it means to compute.

still from Embodied Intelligence video
still from Embodied Intelligence video

These weird virtual creatures evolve their bodies to solve problems

They show how intelligence and body plans are closely linked—and could unlock AI for robots.

seeing is believing concept
seeing is believing concept

Our brains exist in a state of “controlled hallucination”

Three new books lay bare the weirdness of how our brains process the world around us.

We reviewed three at-home covid tests. The results were mixed.

Over-the-counter coronavirus tests are finally available in the US. Some are more accurate and easier to use than others.

Stay connected

Illustration by Rose WongIllustration 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.