@web5/credentials

The @web5/credentials package provides the following functionality:
* creation, signing, verification, and general processing of Verifiable Credentials (VCs).
* Presentation Exchange evaluation

Table of Contents

- VerifiableCredential
- Features
- Usage
- Creating a Verifiable Credential
- Signing a Verifiable Credential
- Verifying a Verifiable Credential
- Parsing a JWT into a Verifiable Credential
- Creating a Status List Credential
- VerifiablePresentation
- Features
- Usage
- Creating a Verifiable Presentation
- Signing a Verifiable Presentation
- Verifying a Verifiable Presentation
- Parsing a JWT into a Verifiable Presentation
- PresentationExchange
- Features
- Usage
- Selecting Credentials
- Satisfying a Presentation Definition
- Create Presentation From Credentials
- Validate Definition
- Validate Submission
- Validate Presentation

VerifiableCredential

VC Features

* Create Verifiable Credentials with flexible data types.
* Sign credentials using decentralized identifiers (DIDs).
* Verify the integrity and authenticity of VCs encoded as JSON Web Tokens (JWTs).
* Parse JWT representations of VCs into VerifiableCredential instances.

VC Usage

Along with the credentials package you will need command and dids for most of the Verifiable Credentials operations

``bash
npm install @web5/common
npm install @web5/dids
npm install @web5/credentials
`

Then to import:

`javascript
import { VerifiableCredential, VerifiablePresentation, PresentationExchange } from '@web5/credentials';
`

$3

Create a new VerifiableCredential with the following parameters:

- type: Type of the credential.
- issuer: Issuer URI.
- subject: Subject URI.
- data: Credential data.
- issuanceDate? (Optional) The Issuance Date. Defaults to current date if not specified.
- expirationDate?: (Optional) Expiration Date.
- credentialStatus?: Optional. The credential status lookup information to see if credential is revoked.
- credentialSchema?: (Optional) The credential schema of the credential.
- evidence?: (Optional) Evidence can be included by an issuer to provide the verifier with additional supporting information in a verifiable credential.

`javascript
class StreetCredibility {
constructor(localRespect, legit) {
this.localRespect = localRespect;
this.legit = legit;
}
}

const vc: VerifiableCredential = await VerifiableCredential.create({
type: "StreetCred",
issuer: "did:example:issuer",
subject: "did:example:subject",
data: new StreetCredibility("high", true)
});
`

$3


Sign a VerifiableCredential with a DID:

- did: The did that is signing the VC.

First create a Did object as follows:

`javascript
import { DidJwk } from '@web5/dids';
const issuer: BearerDid = await DidJwk.create();
`

Then sign the VC using the did object
`javascript
const vcJwt: string = await vc.sign({ did: issuer });
`

$3

Verify the integrity and authenticity of a Verifiable Credential

- vcJwt: The VC in JWT format as a String.

`javascript
try {
await VerifiableCredential.verify({ vcJwt: signedVcJwt })
console.log("VC Verification successful!")
} catch (e: Error) {
console.log("VC Verification failed: ${e.message}")
}
`

$3


Parse a JWT into a VerifiableCredential instance

vcJwt: The VC JWT as a String.

`javascript
const vc: VerifiableCredential = VerifiableCredential.parseJwt({ vcJwt: signedVcJwt })
`

$3


Create a new StatusListCredential with the following parameters:

- statusListCredentialId: The id used for the resolvable path to the status list credential [String].
- issuer: The issuer URI of the status list credential, as a [String].
- statusPurpose: The status purpose of the status list cred, eg: revocation, as a [StatusPurpose].
- credentialsToDisable: The credentials to be marked as revoked/suspended (status bit set to 1) in the status list.

`javascript
const statusListCredential: VerifiableCredential = StatusListCredential.create({
statusListCredentialId : 'https://statuslistcred.com/123',
issuer : "did:example:issuer",
statusPurpose : 'revocation',
credentialsToDisable : [credWithCredStatus]
});
`

To associate the status list credential with a revocable credential have the statusListCredential parameter match up to the statusListCredentialId parameter. Here is a full example:

`javascript
const credentialStatus: StatusList2021Entry = {
id : 'cred-with-status-id',
type : 'StatusList2021Entry',
statusPurpose : 'revocation',
statusListIndex : '94567',
statusListCredential : 'https://statuslistcred.com/123',
};

const credWithCredStatus: VerifiableCredential = await VerifiableCredential.create({
type : 'StreetCred',
issuer : issuerDid.uri,
subject : subjectDid.uri,
data : new StreetCredibility('high', true),
credentialStatus : credentialStatus
});

// Create a status list credential with and revoke the credWithCredStatus
const statusListCredential: VerifiableCredential = StatusListCredential.create({
statusListCredentialId : 'https://statuslistcred.com/123',
issuer : "did:example:issuer",
statusPurpose : 'revocation',
credentialsToDisable : [credWithCredStatus]
});
`

VerifiablePresentation

VP Features

* Create Verifiable Presentation with flexible data types.
* Sign presentations using decentralized identifiers (DIDs).
* Verify the integrity and authenticity of VPs encoded as JSON Web Tokens (JWTs).
* Parse JWT representations of VPs into VerifiablePresentation instances.

$3

$3

Create a new VerifiablePresentation with the following parameters:

- holder: The holder URI of the presentation, as a string..
- vcJwts: The JWTs of the credentials to be included in the presentation.
- type: Optional type of the presentation, can be a string or an array of strings.
- additionalData: Optional additional data to be included in the presentation.

`javascript
const vp: VerifiablePresentation = await VerifiablePresentation.create({
type: 'PresentationSubmission',
holder: 'did:ex:holder',
vcJwts: vcJwts,
additionalData: { 'arbitrary': 'data' }
});
`

$3


Sign a VerifiablePresentation with a DID:

- did: The did that is signing the VP

Sign the VP using the did object
`javascript
const vpJwt: string = await vp.sign({ did: issuer });
`

$3

Verify the integrity and authenticity of a Verifiable Presentation

- vpJwt: The VP in JWT format as a String.

`javascript
try {
await VerifiablePresentation.verify({ vpJwt: signedVpJwt })
console.log("VP Verification successful!")
} catch (e: Error) {
console.log("VP Verification failed: ${e.message}")
}
`

$3


Parse a JWT into a VerifiablePresentation instance

vpJwt: The VP JWT as a String.

`javascript
const parsedVp: VerifiablePresentation = VerifiablePresentation.parseJwt({ vcJwt: signedVcJwt })
`

PresentationExchange

PresentationExchange is designed to facilitate the creation of a Verifiable Presentation by providing tools to select and validate Verifiable Credentials against defined criteria.

$3

- Select credentials that satisfy a given presentation definition.
- Validate if a Verifiable Credential JWT satisfies a Presentation Definition.
- Validate input descriptors within Presentation Definitions.




$3

$3

Select Verifiable Credentials that meet the criteria of a given presentation definition.

- vcJwts: The list of Verifiable Credentials to select from.
- presentationDefinition The Presentation Definition to match against.

This returns a list of the vcJwts that are acceptable in the presentation definition.
`javascript
const selectedCredentialsJwts: string[] = PresentationExchange.selectCredentials({
vcJwts: signedVcJwts,
presentationDefinition: presentationDefinition
})
`

$3

Validate if a Verifiable Credential JWT satisfies the given presentation definition. Will return an error if the evaluation results in warnings or errors.

- vcJwts: The list of Verifiable Credentials to select from.
- presentationDefinition The Presentation Definition to match against.

`javascript
try {
PresentationExchange.satisfiesPresentationDefinition({ vcJwts: signedVcJwts, presentationDefinition: presentationDefinition })
console.log("vcJwts satisfies Presentation Definition!")
} catch (e: Error) {
console.log("Verification failed: ${e.message}")
}
`

$3

Creates a presentation from a list of Verifiable Credentials that satisfy a given presentation definition. This function initializes the Presentation Exchange (PEX) process, validates the presentation definition, evaluates the credentials against the definition, and finally constructs the presentation result if the evaluation is successful.

- vcJwts: The list of Verifiable Credentials to select from.
- presentationDefinition The Presentation Definition to match against.

`javascript
const presentationResult: PresentationResult = PresentationExchange.createPresentationFromCredentials({ vcJwts: signedVcJwts, presentationDefinition: presentationDefinition })
`

$3

This method validates whether an object is usable as a presentation definition or not.

- presentationDefinition The Presentation Definition to validate

`javascript
const valid: Validated = PresentationExchange.validateDefinition({ presentationDefinition })
`

$3

This method validates whether an object is usable as a presentation submission or not.

- presentationSubmission The Presentation Submission to validate

`javascript
const valid: Validated = PresentationExchange.validateSubmission({ presentationSubmission })
`

$3

Evaluates a presentation against a presentation definition.

- presentationDefinition The Presentation Definition to validate
- presentation The Presentation

`javascript
const evaluationResults: EvaluationResults = PresentationExchange.evaluatePresentation({ presentationDefinition, presentation })
``