DECODE/BAR use case

Use Case ID - Use Case title

DEC01 - Online voting platform with privacy

Owner of Use Case

Stefano Bocconi - DECODE project

Description

The DECODE project is extending an existing online voting platform according to the principles of data minimisation and data ownership and sovereignty. This implies that:

• Users can vote anonymously. The only requirements to be able to vote are a proof of residence in the city where the poll is open and of being older than a certain age.
• Users must be able to vote at max once, but can change their vote.
• Votes must be registered and kept for accountability of the voting process.

Requirements

Related functional requirements

• Eligibility for voting is based on and must be determined based only on two conditions: the user is resident in the area of the poll and the user is older than the minimum age to vote
• Each vote must be recorded so that final poll result can be calculated, without revealing the user identity
• The process must be verifiable for correctness by any party (transparency)

Component(s)

• A digital wallet that each user has, containing verified attributes such as name, age, residency, etc.
• An authorisation system that requires particular verified user attributes to allow access (in this case to the voting system)
• A trusted authority (such as a municipality) that certifies the authenticity of (some of) the user attributes contained in the wallet
• A Distributed Ledger that records each vote.

Types/classes of data involved

• User attributes
• Votes

Actors

• A local municipality or other instances that want to put out a public poll
• Users that might want to participate in the poll
• A certifying instance (such as the same local municipality)

Preconditions

• Users have (installed) a wallet
• Polling system supports attribute-based authorisations
• Users have means to certify their attributes

Postconditions

• Polling can be verified by any party for correctness.

Normal Flow

• User interacts with a trusted authority that certifies (digitally sign) particular attributes of the user, such as residency and age
• User records these attributes in their digital wallet
• Local municipality publishes a public poll
• User is authorised to vote in the polling system by allowing their wallet to share the required attributes with the polling system (residency and age)
• User votes
• (Optional) User changes their vote
• Local municipality closes the poll and calculates the results.
• Any party can verify the results of the poll

Alternate Flows

• User interacts with a trusted authority that certifies (digitally sign) particular attributes of the user, such as residency and age
• User records these attributes in their digital wallet
• Local municipality publishes a public poll
• User is not authorised to vote in the polling system because:
  • They do not allow their wallet to share the required attributes with the polling system (residency and age)
  • They do not possess the correct attributes

Evaluation of UC and requirements realisation

(e.g. manual, automatically...)