Proof of age (18+)

Overview

Customers present a verifiable age credential to prove they are 18+ for restricted products or venue entry, without handing over a full identity document.

The verifier gets a policy answer, not a copy of the customer’s identity record.

Why it matters

Physical ID checks are slow, expose extra data, and are hard to audit. They can also create inconsistent decisions across venues, stores, and online services.

Verifiable Credentials create a cleaner model:

• an accepted authority issues an age credential
• the customer presents only the proof needed for the restricted transaction
• the verifier checks issuer trust and credential status
• the decision can be recorded without retaining unnecessary personal data

Ecosystem roles

• Issuer: Government authority, registrar, or other accepted age credential issuer.
• Holder: Customer storing the credential in a wallet.
• Verifier: Retailer, venue, delivery service, or online restricted service.
• Trust governance: The rules that define accepted issuers, age thresholds, status checks, and fallback paths.

Trust decision

The verifier decision is narrow: is this customer at least 18 for this transaction right now?

The proof should answer that question without disclosing address, document number, or unrelated identity attributes.

Privacy and assurance

Privacy depends on requesting the minimum claim needed for the sale or entry decision. Assurance depends on proof integrity, issuer trust, expiry, and status checking.

For regulated products and venues, the verifier should also record enough evidence of the decision to support audit without storing full credential payloads.

Implementation notes

• Define the age threshold and accepted issuer list in verifier policy.
• Support online, in-person, and assisted verification flows where relevant.
• Avoid retaining full credentials when a decision result and transaction reference are sufficient.
• Provide fallback handling for customers without supported wallets.

Objective

Confirm a customer meets the minimum age requirement.

Description

Verify an age credential before allowing a restricted product purchase, delivery, service, or venue entry.

Actors

Age credential issuer; customer; retailer, venue, delivery provider, or online service.

Dependencies

Issuer trust registry, age credential schema, verifier policy, and status endpoint.

Preconditions

The customer holds a valid age credential and can present it to the verifier.

Postconditions

Sale, delivery, service, or entry is allowed, denied, or escalated based on verified proof.

flowchart LR
    GOV@{icon: "tabler:id", label: "Government authority", pos: "b"} -->|Issues age VC| WAL@{icon: "tabler:wallet", label: "Wallet", pos: "b"}
    WAL -->|Present age proof| VER@{icon: "tabler:building-store", label: "Retailer / venue", pos: "b"}
    VER -->|Check status| REG@{icon: "tabler:book", label: "Registry/status", pos: "b"}

sequenceDiagram
    participant Government
    participant Wallet
    participant Customer
    participant Verifier as Retailer / venue
    participant Registry as Registry/status

    Government-->>Wallet: Issue age VC
    Customer->>Verifier: Request purchase or entry
    Verifier->>Wallet: Request proof
    Wallet-->>Verifier: Present age proof
    Verifier->>Registry: Validate issuer and status
    Registry-->>Verifier: Valid
    Verifier-->>Customer: Allow or deny