Confirming eligibility while minimizing data collection
Eligibility checks can require people to share more personal information than is necessary for a particular service. For example, a service may collect a person’s full date of birth when it only needs to know whether they meet a minimum age requirement. An application using Ethereum could allow someone to prove that they meet the requirement while limiting the personal data disclosed to the service.
One possible approach
In this example, a person needs to show that they meet a service’s minimum-age requirement without sharing their full identity document or date of birth.
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Set the eligibility rules
The service defines the minimum age and which trusted sources of information it will accept, such as a government identity system or another recognized authority. These rules determine what a person needs to prove in order to qualify.
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Create a privacy-preserving proof
Using age information confirmed by one of these accepted sources, the person creates a proof that they meet the minimum age requirement. The proof confirms only that requirement, without revealing their date of birth or full identity document.
This is known as a zero-knowledge proof: a cryptographic method for proving that a requirement has been met without revealing the underlying personal information.
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Verify the proof
The service sends the proof to a smart contract: a program that runs on Ethereum. The smart contract checks whether the proof satisfies the service’s verification rules and returns the result. It does not receive the person’s full identity document or date of birth.
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Continue using the service
The service can use the verification result to determine eligibility without receiving the underlying personal information.
What Ethereum enables
Ethereum can provide shared infrastructure for verifying eligibility while limiting the personal data disclosed to a service. Verification rules can be checked independently, reducing reliance on a single identity or technology provider and supporting data minimization across services.