A verifiable claim is a qualification, achievement, quality, or piece of information about an entity's background such as a name, government ID, payment provider, home address, or university degree. Such a claim describes a quality or qualities, property or properties of an entity which establish its existence and uniqueness. The use cases outlined here are provided in order to make progress toward possible future standardization and interoperability of both low and high-stakes claims with the goals of storing, transmitting, and receiving digitally verifiable proof of attributes such as qualifications and achievements. The use cases in this document focus on concrete scenarios that the technology defined by the group should address.

This document represents a concise but limited collection of use cases readers should review in conjunction with the proposed Charter for a Verifiable Claims Working Group.

Introduction

The Verifiable Claims Task Force of the Web Payments Interest and Credentials Community Groups at the W3C is investigating the requirements around secure, verifiable, and richly descriptive "claims". The goal of the Task Force is to determine if there is a sufficient understanding and need to merit the creation of a W3C Working Group to develop Recommendations in this space.

This document does NOT attempt to define an architecture for the support of Verifiable Claims. Instead it expresses the sorts of needs that real users have that could be addressed through support for some sort of self-soverign claim environment. It attempts to use terminology that is consistent with the other deliverables of the Verifiable Claims Task Force (you can see the relevant terms in Appendix A).

Importance of this work

Entities (people, organizations, devices) need to make many kinds of claims as part of their everyday activities. As more and more of these important activities move to the Internet, entities need to be able to transmit instantly verifiable claims (e.g., about their location, accomplishments, value, what-have-you). From educational records to payment account access, the next generation of web applications will authorize entities to perform actions based on rich sets of credentials issued by trusted parties. Human- and machine-mediated decisions about job applications, account access, collaboration, and professional development will depend on filtering and analyzing growing amounts of data. It is essential that data be verifiable.

Standardization of digital claim technologies makes it possible for many stakeholders to issue, earn, and trust these essential records about their counterparties, without being locked into proprietary platforms.

Use case model

This document presents an aggregate use case model, comprised of Needs, Roles, Tasks, and Sequences. Taken together, these models define the use cases that the Verifiable Claims Working Group will address.

User needs define the problem space Verifiable Claims addresses. User Roles specify the roles different entities play when interacting with Verifiable Claims. Tasks define the functions users can accomplish and sequences demonstrate how tasks might be realized by interactions between entities over time.

As with all models, this use case model is neither exhaustive nor complete. The listed uses cannot exhaustively capture all possible use cases. Similarly, the models do not completely characterize the use cases represented. However, the combined model provides specific, coherent guidance for the work ahead.

User roles

There are four roles supported by Verifiable Claims: Issuer, Inspector, Subject, and Holder.

Verifiable Claim User Roles
Issuer
The entity that creates a claim and associates it with a particular subject.
Inspector
The entity verifying a claim about a given subject.
Subject
The entity about whom a claim is issued.
Holder
The entity who controls a particular claim. Often the subject of the claim, but not always. For example, the subject of a claim might be a pet who has received a vaccination. The holder of that claim is likely the pet's owner, not the pet. A holder is typically the initiator of the transmission of a claim.

User needs

Verifiable Claims address user needs in a number of key domains:

Verifiable Claim Creation Flow Description

Finance

The Finance domain includes banking, brokerage, insurance, and other industries where there is a high value placed on knwoing exactly with whom you are dealing.

F.1 Reuse know your customer
Jane is opening an account at MidBank in Finland. As part of that process, the bank asks her to provide two from a variety of possible sources to confirm her identity - a so called "Know Your Customer" check. She selects government-supplied verifiable claims that confirm she receives postal mail at a certain address and that she has a national ID card. Confirming these allows the bank to open her account and be confident in her identity when she conducts transactions.
Now that the account is open, Jane is issued a digitally signed credential for her checking account at MidBank. This credential verifies that Jane has an account at MidBank and has access to her associated checking account. Since MidBank (and all banks in Finland) are required to perform "Know Your Customer" checks on accounts, this credential can also be used as sufficient verification by other financial institutions. This can help Jane assure destination banks that she is verified, thereby allaying concerns about misdirected transactions and money laundering.
F.2 Money transfer
Susan wants to send funds to her family in another country via a popular money transfer service. She has verifiable claims in her credential repository that can be used to share her identity profile. She has also been sent a claim from her family verifying their banking information. By sharing these with the money transfer service, they can automatically verify the source and destination of funds, thus being confident in the delivery of those funds and satisfying various regulations regarding prevention of money laundering.
F.3 Closing account
John opens a checking account at Big Bank Co and is issued a Verifiable Claim indicating that the account exists, that the bank verified John's identity, and that John has access to the account. Some time later, John is moving to a new city and decides to close that account. Big Bank Co needs to revoke that claim as part of their normal account closing process.
F.4 Trying out a new service
Nikita has several accounts with BigBank, as well as a brokerage account with WallStreetCo. She had placed all of her claims in a credential repository at BigBank that came free when she opened her accounts. WallStreetCo is now offering a new repository that has an interface she thinks she will prefer. Nikita copies her claims from BigBank into the repository at WallStreetCo to experiment with their service, but continues to use the service from BigBank while she is testing.
F.5 New bank account from home
Alice wants to open a new bank account. BigOnlineBank offers the ability to do this from home if she can provide electronic credentials. She offers government issued certificates that verify her identity (address, national identity number, etc.), and opens her new account from her couch.

Education

The education domain includes all levels of the educational experience; from primary through professional continuing education.

E.1 Digital transcript
Joleen is the registrar of Mega University and, by virtue of her office, is responsible for the integrity, accuracy, and security of academic records. Joleen has been a pioneering registrar in advocating an 'extended transcript' that includes not only the standard set of course grades but also adds supplementary information on learner competencies. These might include work experiences and non-educational but marketable skills. Upon the request of her students Joleen issues digital credentials that encapsulates an extended transcript.
E.2 Taking a test
Eunice is about to take her ACT (a test used to evaluate her readiness for college). When she arrives at the testing center, she is required to present identification. Her government-issued identity certificate is acceptable, as the verifiable claims contained in it reflect all of the required attributes and it is impossible to counterfeit.
E.3 Transferring schools
Rocky is an undergraduate student at Wossamotta U. His school provides a credential repository service to all students and alumni, so he chooses to use it. In his third year, Rocky decides to transfer to Moosylvania Tech. They do not offer a service, but he does not want to continue to use the service of his old (and now rival school) so he moves his claims to the service offered by his bank without needing to have them reissued.
E.4 Online classes
In MOOC and other on-line learning systems, being able to reliably identify participants is vital to ensure the individual evaluation and certification. Nick is participating in a course online and takes a test. He is required to provide his credentials to prove his identity before the test, and then to allow the system to issue a verifiable claim regarding the results of his test.

Healthcare

Privacy is critically important in the healthcare industry. This domain looks at everything from physicial interaction to connecting patients and providers with service organizations.

H.1 Prescribing
Barney is a physician, and has recently become board certified in his state. The state's board issues Barney a digital certificate confirming that he is certified to practice medicine in that state. Barney can now use this certificate when writing prescriptions and referrals, thereby improving accountability and verifiability.
H.2 Online pharmacy
iPharmacy receives a prescription for Bob electronically from a local clinic. It includes a certificate about the physician that issued the prescription as well as one about Bob. iPharmacy's system automatically verifies the ability of the physician to write prescriptions, as well as Bob's insurance coverage. When Bob arrives to pick up his medication, iPharmacy further correlates his identity with the certificate, thereby improving the end-to-end accountability of their system.
H.3 Insurance claim
Tracy has a sore throat soon after moving to a new town. She finds a physician through her health care network and goes in for treatment. She is a new patient, so the clinic needs to know who she is and how she will be paying. When checking in, she presents her verifiable claim that demonstrates her identity and her proof of insurance. When the clinc submits this to the insurance company, they can automatically ascertain that she submitted her proof of identity and insurance to the provider and granted the physician the ability to submit the claim for payment.
H.4 Traveling illness
John is on the vacation of a lifetime, travelling the world. Falling ill, he visits a health clinic in a country in which he does not live. At the clinic he is asked for proof of identity. He provides a credential that verifies his name and address, but elects not to disclose his marital status nor his social security number, as those are neither requested nor required at this clinic. He further marks the disclosure as expiring in 30 days - he does not want his information verifiable after that time.

Retail

The retail domain encompasses all things where there is an exchange of value on an individual level. This includes brick-and-mortar store fronts, web-only venues, and even person-to-person sales.

R.1 Address verification
Francis has found the perfect pair of shoes. When processing orders, Giant Shoe Company wants to be certain that his shipping address is accurate (inaccurate addresses are very expensive in terms of customer service). They offer a discount for customers who make verifiable addresses available as part of the checkout process. Francis offers his certificate and gets the perfect shoes for even less than he expected.
R.2 Adult beverages
June goes to her local beer and wine store to buy a bottle of wine. She submits her identity credential that lets the liquor store owner know that she is over 21 without having to reveal her actual date of birth, her address, or her state ID number.

Professional credentials

In many aspects of life it is important to know that entities are who they say they are, and that they can do what they say. Professional accreditation is one way of learning about the abilities of an entity. Being able to verify these credentials is essential to their value.

C.1 Find a doctor
Jason is looking for a new primary care physician. His health provider includes information on their web site about the physicians they have on staff, including verifiable credentials about their education, board certification, and continuing education. Jason can verify these credentials and be confident that his new physician satisfies his requirements.
C.2 Busy doctor
Barney was a board certified physician, but he ran out of time to complete his contuning education requirements and his certification lapsed. Since the board can revoke his certification, credential inspectors will automatically be aware that he can no longer issue prescriptions or perform medical procedures.
C.3 Bad university
Jane was issued a certificate by BigTraining Co., indicating that she was a trained Project Manager. It was later discovered that BigTraining Co. was not actually training anyone, and their organization's certificate was revoked via the US Department of Education's Accreditation Database. Jane's credential is therefore invalid, and prospective employers will be aware of this when they check her certifications.
C.4 New employer
Jessica is a medical doctor practicing in the United States. She has a variety of digital claims that explain her qualifications, schooling, continuing education achievements, and board certifications. These are all stored in the credential repository provided by her employer. When she is offered a position with another health provider network, she can automatically transfer all of these claims to her new employer.
C.5 Social authority
Josie is a healthcare worker that has created a profile on a professional social network to make herself readily available for new opportunities in the workforce. She lists her employment history and credentials including degrees, certificates, and digital badges. The website requests verification of her credential claims in order for her credentials to visible when she posts messages. Josie authorizes the sharing of the relevant claims with the website, and the site verifies them before allowing Josie to expose them.
"Freedom?" is an online forum that encourages free discussion about issues controversial in Freedonia. The forum allows users to register anonymous accounts, but it also allows users to obtain badges based upon real world certifications. Paula has been certified as an aid worker, and wishes that information to be marked on her posts. She shares her certificate with the forum, but limits it to only verifying that she is the holder of the certificate, that she is the subject of it, and that she is an aid worker. In this way she maintains her anonymity in this controversial forum while still being able to assist her fellow countrymen.
C.6 Job applicant
Software Co. has posted an open position online and they are receiving thousands of applications. Cindy has applied for the job. Unlike many applicants, she has attached her education credentials - college degree, additional specific software training, etc. Software Co. evaluates these credentials automatically as they receive her application. Because her materials are verifiable and verified, her application is immediately forwarded as a viable candidate.

Legal identity

For many transactions, an entity must be able to prove some aspect of their identity in a way that can be quickly verified. Governments and other widely recognized entities are well positioned to provide such identification in a verifiable digital form.

L.1 Digital driving license
Asako just passed the final test to receive a drivers license. As she is still a new driver, and may be pulled over for a traffic violation, she would like to receive a credential that asserts a claim that she has right to drive a car. She requests a credential from the certifying authority (issuer) that she can use to prove to the officer (credential inspector) that her claim is valid.
L.2 Seamless immigration
Tom is a frequent international traveler. In order to speed processing through immigration check points, he applies for a digital passport from his governmental authority. After satisfying background check requirements, the authority issues Tom an electronic version of his passport. This version is verifiable and retains a history of all the places he visits so that immigration officials can quickly and easily evaluate his suitability as a visitor to their country. Once they are satisfied, the will automatically add the details of this new visit to Tom's passport.
L.3 Speedy air travel
Security for air travel is more and more rigorous, requiring more and more time to validate each passenger. Ivan has a collection of verifiable claims that are assembed into his air travel Identity Profile. When Ivan needs to pass through a security checkpoint at his airport, he presents this profile before entering the line. Because his identification can be immediately and automatically verified, he is permitted to skip the long line and go straight to the metal detector.
L.4 Refugee crisis
Thousands of people each year are displaced because of man-made and natural disasters. Anoushka is one such, having been forced to flee her village along with her mother and younger brother. They reach an IFRC center just across the broder in a relatively safe area, but with no documentation. Since the government of her homeland is in turmoil, there is no way for the IFRC staff to easilty establish their identities. Fortunately, Anoushka had been issued a self-soverign proof of birth, attached to which is the proof of birth and marriage for her parents. She is able to retrieve this because it is available from many places on the Internet. Since it is verifiable, the IFRC is comfortable vouching for them and resettling them in a safer area for the duration of the conflict.

User tasks

Use cases are often used as a driver for requirements. While the users of Verifiable Claims have needs across many domains, the tasks associated with those needs span the domains. This section summarizes those tasks, as well as requirements related to the tasks, and maps the tasks and requirements back to the associated needs.

It is worth noting that the subject may or may not be the same entity as the holder. There are no tasks in these examples that require participation of the subject.

Verifiable Claim User Tasks

Issue claim

Requirement
It MUST be possible for any entity to issue a verifiable claim.
Motivation
Individuals and organizations need a way to issue claims about themselves or others that can be verified and trusted.
Needs
F.1, E.1, L.1, H.1

Assert claim

Requirement
It MUST be possible for the holder of a claim to restrict the amount of information exposed in a claim they choose to share. It also MUST be possible for the holder to limit the duration for which that information is shared.
Motivations
Credentials may be issued about a subject that include multiple attributes, only some of which are required when verifying a specific criteria is satisfied. The holder should have the ability to satisfy the criteria without revealing additional attributes that are not required.
Needs
R.2, H.4

Verify claim

Requirement
It MUST be possible for an inspector to verify that the credential is an authentic statement of an issuer's claims about the subject. The verifying entity must have the capability to connect the issuer’s identity to its credential identifier and the subject's identity to their identifier as indicated in the credential. The issuer’s verification information, such as its public key, must be discoverable from the credential record and verifiably linked to the issuer. It MUST be possible to do this in an automated fashion.
Motivations
In many environments (such as order processing) information such as a payer's address, citizenship, or age need to be automatically verified in order to complete the transaction.
Needs
F.2, C.1, E.2, R.1, F.5, H.2, C.6

Store / Move claim

Requirement
It MUST be possible for the holder of a claim to store that claim in one or more credential repositories. It MUST also be possible for the holder to move a claim among credential repositories.
Motivation
A claim is under the control of its holder. That holder will choose where their claims are stored based upon a variety of factors (e.g., employer requirements, convenience, service levels, business intelligence). The holder needs to be able to easily choose among various credential repositories, and also to be able to migrate their claims to another without requesting new claims from the claim issuer. Competition in this space will foster innovation and cost savings. Multiple providers in this space will improve reliabilty.
Needs
F.4, E.3, C.4

Retrieve claim

Requirement
It MUST be possible for a holder to select if and which appropriate credential should be sent to an inspector.
Motivations
An inspector may require that a holder verify aspects of their suitability for a transaction. In this case, the holder must be able to select which, if any, Verifiable Claim stored with their Credential Repository is used to satisfy the inspector.
Needs
C.5, E.4

Revoke claim

Requirement
It MUST be possible for the issuer of a claim to revoke it, after which it will no longer satisfy verification procedures.
Motivation
An entity (issuer) discovers that a claim they have issued and are endorsing for an end user (subject), is no longer valid and wishes to revoke the issued claim.
Needs
F.3, C.2, C.3

User sequences

The transaction examples in this section basic ways in which Verifiable Claims might be used. They are not meant to be architecturally constraining. Instead, they are meant to help illustrate the basic way it could be done in a typical commerce situation. Again - please remember that it is just an example, and should not be thought of as the canonical way such a claims environment must be implemented.

How a verifiable claim might be created

In this first example, a user will request a Verifiable Claim - a confirmation of their identity. Consider this illustration:

Verifiable Claim Creation Flow Description

Expanding on these steps:

  1. Jane asks her User Agent to help her get a Verifiable Claim about her identity.
  2. Her user agent connects her to a certificate issuer that is able to verify her identity.
  3. The issuer examines her documentation.
  4. They are satisfied, so the issuer generates a Verifiable Claim for Jane that includes information about her identity linked to their own trusted credential.
  5. The issuer delivers the credential back to Jane's User Agent.
  6. Jane views the credential to ensure it reflects her requirements.
  7. When she is satisfied, she instructs her User Agent to save the Verifiable Claim so she can use it in the future.
  8. The UA communicates with her Credential Repository, instructing it to store the new claim.
  9. The Credential Repository returns a list of the claims it is holding for Jane to the UA.
  10. The UA shows Jane her claim collection - confirming everything she has available.

How a verifiable claim might be used

In this example, a holder of a claim needs to use that claim in a typical commerce situation:

Verifiable Claim Usage Flow Diagram
  1. Jane decides to shop on the web site WinesOfTheWorld.example.com (merchant).
  2. The merchant's site requires Jane be 21 years of age and requests Jane prove this (via a user agent-supported API call).
  3. Jane's user agent asks her credential repository for the proof.
  4. The credential repository shows Jane three Verifiable Claims it knows of that can assert this claim (e.g., her passport, driving license, and birth certificate).
  5. Jane selects one of these and authorizes that it be shared with the merchant.
  6. The credential repository returns the selected claim as a response to the user agent-supported API call, which in turn delivers it to the merchant.
  7. The merchant's server verifies that the claim is valid and satisfies the requirement.
  8. The merchant redirects the user agent to the web site with appropriate authorization.

Terminology

Acknowledgements

The editors are thankful to the contributions from the Web Payments Workshop, the Web Payments Community Group, the Web Payments Interest Group, the Credentials Community Group, and the Verifiable Claims Task Force.