Distributed Identity Assurance

Full Title or Meme

Identity Proofing has often been viewed as a centralized function of a Credential Service Provider (CSP), but it can be more efficiently be realized using existing Identity Proofing in many real-world locations.

Context

This concept of Distributed Identity Proofing is described here as a use case for attaining IAL2 identifier assurance in a Trustworthy Healthcare Ecosystem.

Goal

To allow online patient's of one provider to leverage existing Identity Proofing with other providers.

Actors

1. Actor: Patient of one healthcare provider seeking services at another (refereed) provider.
2. Actor: Patient's Phone as Health Care Credential
3. Actor: Verifier of claim with Identifier.
4. Actor: Existing provier of health care services.
5. Actor: Referred provider of health care services.

Note that it is possible that the patient's guardian (parent) is acting on the patient's behalf in this use case, but that should have no appreciable impact on the flow described here.

Preconditions

• The Patient has acquired a mobile phone for any major provider.
• The Patient has registered at a [primary] healthcare provider (PHP).
• The Patient has been (or will be) referred to another healthcare provider.

Scenarios

Primary Scenario:

1. Consumer signs into supplier and has never purchased liquor from this site.
2. Consumer selects to purchase liquor item
3. Supplier asks user for over 21 proof with a nonce.
4. Consumer sends verifiable claim of over 21 they acquired from verifier.
5. Supplier asks verifier for proof. (This would be by redirect to verifier through user browser)
6. Verifier supplies validated claim (or statement of non-revocation) bound to nonce by redirect to Supplier, if this VC is bound to the user’s session with supplier, it can have a lifetime of the duration of bound session.
7. Monetization is by direct micro payment (on the order of $.05) from supplier to verifier.

Alternative Paths:

1. Consumer selects to purchase liquor item.
2. Supplier asks user for over 21 proof with a nonce.
3. Consumer asks verifier directly for proof with nonce from Supplier.
4. Verifier asks consumer to enter token for proof of presence.
5. Verifier send validated claim with nonce of supplier with short expiration time (10-20 mins - alternate life time of duration of session).
6. Consumer sends verified claim to supplier.
7. Monetization is by advertising from verifier to consumer.

A different path using biometrics:

1. Yoti, a London-based startup which wants to become the “world’s trusted identity platform”, is one of many attempts to provide such a service. Its system stores government id documents and biometrics. If a user wants to buy a bottle of wine at a supermarket self-check-out and needs to prove their age, they scan a qr code and take a selfie using Yoti’s app. The retailer can be sure of their age, but no one has seen their name or nationality. From the Financial Times.

Failed Paths:

1. User does not get verified claim for some reason.
2. Verified claims fails validation at supplier.
3. Verified claims are false.

Results

Accepted Risks:

1. The consumer is not over-21 and has buddy’s token to enter into computer.
2. Session hijacking mitigated with HTTPS and session cookies.
3. MitM attacks mitigated by hardware token bound to origin URL of verifier.
4. Note that the late binding token could be bound to supplier as well as needed.
5. The identity of the verifier/validator is discoverable by the supplier.
6. User makes choices on which attributes are trusted for sharing with the supplier.

Post Condition:

1. If validation accepted, and consumer completes payment, the restricted goods are shipped to the consumer by the supplier.
2. Note that at the end of the process of validating the user’s age, the state issued license to sell alcoholic beverages will determine which path to use. The penalty for the supplier using the wrong path is loss of the license to sell alcohol.

Examples:

1. Late binding token - FIDO U2F token, TEE TPM VSC, etc.
2. Client side code - javascript in a browser, native app, etc.

Dependencies::

1. Web Sites must be trusted before any user information is released.
2. Trust federations can be used to help users make informed decisions.
3. User consent and trust must begin with no user information transferred.
4. Standards exist to collect needed attributes where-ever they may be.

Workflow Diagram

TK

References

• The Identity Proofing Use Case describes the existing, centralized Identity Proofing with a Registration Authority and Credential Service Provider.