The Risks of EVoting Machines

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The Risks of E-Voting Machines

• Dan S. Wallach
• Department of Computer Science
• Rice University

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Clearly, voting machines matter

• Failure of machines ? failure of democracy
• Potentially dire consequences

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Many potential failure modes

• Human-factors issues

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Many potential failure modes

• Mechanical flaws

Bush
Bush
Gore
Gore
5
What about e-voting?

• Several different forms
• Internet voting (used on many college campuses)
• Computerized voting machines

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Obvious benefits

• Better human factors
• Can check for overvoting
• Can review for mistakes
• Interfaces for blind users
• Its new
• No antiquated machinery
• Non-traditional election styles
• Condorcet voting, approval voting, etc.

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Obvious flaws

• Indication to voter that vote is recorded?
• No paper to drop in ballot box
• No satisfying thunk from mechanical gears
• Last-minute voters remorse?
• Paper ballot can tear up, get another one
• Mechanical / electronic machines done is done

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How e-voting works

• Inside the polling place (Hart architecture)

network
Base station
Voting machine

Memory
Memory
Code
Code
Card
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Buggy code?

• Write bad data to all three memories?

network
Base station
Voting machine

Memory
Memory
Code
Code
Memory
Memory
Card
Card
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But in Brazil

• Electronic voting since 1996
• Paper built-in for newest systems
• Type number for your candidate
• Screen shows picture
• Paper held behind glass verifiable, but not
  touchable

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Threat models vs. real world

• To a computer scientist
• Add paper remove code from the TCB
• Paper seen by voter ? voter-verifiable audit
  trail
• Cost / complexity to defraud election increases
• In the real world
• Accessibility community hates paper
• Vendors need standards
• And still advocate security through obscurity
• Municipalities required to upgrade machines by
  04
• Security people seen as paranoid

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Ongoing advocacy

• David Dills petition
• Lots of action happening in California
• Vendors slowly changing their tune
• You require it, well build it.
• Some congressional attention in Washington
• Strongest detractors are accessibility advocates
• Blind voters cannot read paper cards
• You never know who will turn out to be clueless
• League of Women Voters (national office)

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