Anual WorkshopFebruary 5th, 2014

Anonymous yet reliable ePoll application

Italo DacostaSecAnon-DistriNet

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Electronic Polls/Elections

• Gathering opinions on a particular topic

• Determining the most popular choice over a set of options

• Typically targeted to a particular group of people

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Problems

• Generally identifiable– Integrity vs. anonymity

• Users less motivated to freely participate and express opinions

• Users cannot verify their votes– Need to trust the poll organizer

• Difficult to restrict to a target group

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Our Approach

• Rely on anonymous credentials for ballot privacy– PriMan framework

• Design verification capabilities for the bulletin board– Individual verifiability– Universal verifiability– Eligibility verifiability

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Anonymous Credentials

Authentication with a classical credential (X.509)

Name: John DoeGender: MBirthdate: 01/01/1970Address: street 10, LeuvenZip code: 3000 Si

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Proof

Authentication with anonymous credential (Idemix)

Name: John DoeGender: MBirthdate: 01/01/1970Address: street 10, LeuvenZip code: 3000 Si

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Proof

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Our Scenario

• Low to medium scale polls/elections• Low to medium coercion

– E.g., No high-stakes elections

• Untrusted poll organizer– But trusted credential issuer

• Voting over the Internet

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Our ePoll Architecture

Credential Issuance

Issuer ServerCredential Storage &

Retrieval

Account Manager Server

Voting

ePoll Server

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ePoll Protocols

• Registration protocol– Obtain ePoll anonymous credential from Issuer server– User validation (e.g. only one ePoll credential per user)

– E.g., eID, workshop registration number

• Storage & Retrieval protocol– ePoll credentials are securely stored in the Account Manager

server– User authenticates to retrieve her credentials on her desktop

computer or smartphone

• Voting protocol– User selects a poll to participate– User uses her ePoll app and credential to participate in the poll– User can validate their vote was successfully submitted

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Vote Verification

• Poll Integrity Value (PIV)– PIVi = H(i | PIVi-1 | datai)

• Poll Authenticity Value (PAV)– Sign(SK, i | PID | PIVi)

• Work in progress

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Bulletin Board

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Implementation

• Java• PriMan framework• Mobile and Desktop client

ePoll Demonstrator

Questions?

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