Presentation Exchange

In this guide, we'll cover the process of presenting Verifiable Credentials (VCs) to a verifier. This process is known as a Presentation Exchange (PEX) and involves selecting credentials that satisfy a Presentation Definition, creating a presentation based on that definition, and submitting the presentation to a verifier. PEX is typically executed by the user's Wallet application, acting on behalf of the user.

NOTE

Before presenting VCs in a PEX, it's important to note that the VCs would have already been created, signed in a JWT format, and stored in the user's Wallet application.

Presentation Definition

The entity requesting credentials, aka the verifier, will have defined the presentation requirements using a Presentation Definition. This definition specifies the criteria that the VCs need to meet.

Assume a lender has an existing Presentation Definition specifying that applicants must provide VCs to prove their legal name, date of birth, and employment status:

Presentation Definition

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We'll use the Presentation Definition above to present credentials that meet its requirements.

Import PresentationExchange

All methods needed to perform a PEX are in the PresentationExchange class. You can import this class from the @web5/credentials package:

import {
  PresentationExchange,
  VerifiablePresentation,
} from "@web5/credentials";

import web5.sdk.credentials.PresentationExchange
import web5.sdk.credentials.VerifiablePresentation
import web5.sdk.credentials.model.PresentationSubmission
import web5.sdk.credentials.model.*

Select Credentials

A user may possess multiple credentials. To preserve the user's privacy, when creating a Presentation, you'll want to present only the VCs that match the Presentation Definition requirements. This is done with the selectCredentials() method:

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Satisfy Presentation Definition

To ensure that the selected credentials collectively satisfy all of the Presentation Definition's requirements, call the satisfiesPresentationDefinition() method:

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This method will throw an error if all requirements of the Presentation Definition are not satisfied.

Create Presentation

Once you've confirmed that the VCs successfully satisfy the Presentation Definition, you can create a presentation using the createPresentationFromCredentials() method:

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{
  "vpDataModel": {
    "@context": [
      "https://www.w3.org/2018/credentials/v1"
    ],
    "type": [
      "VerifiablePresentation"
    ],
    "id": "urn:uuid:7747d88c-17be-40e0-a10a-0481b330581e",
    "holder": "did:dht:99tgimyf665zdntupjf88yoi8q656g15j8z87r4kdg45578mwacy",
    "verifiableCredential": [
      [
        "eyJhbGciOiJFZERTQSIsInR5cCI6IkpXVCIsImtpZCI6ImRpZDprZXk6ejZNa2VyNDlDbnVnN2hzdkhEZ3Y0NHl2cGR2dE1oNHlMaURYeFM2N2huclVodHQyI3o2TWtlcjQ5Q251Zzdoc3ZIRGd2NDR5dnBkdnRNaDR5TGlEWHhTNjdobnJVaHR0MiJ9.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
}