Verifiable Presentations to QR Code JS Lib _(@digitalbazaar/vpqr)_


> An isomorphic JS (for Node.js and browser) library that takes a Verifiable Presentation, compresses it via CBOR-LD, and turns it into a QR Code.

Table of Contents

- Background
- Security
- Install
- Usage
- Contribute
- Commercial Support
- License

Background

TBD

Security

TBD

Install

- Browsers and Node.js 14+ are supported.

To install from NPM:

``
npm install @digitalbazaar/vpqr
`

To install locally (for development):

`
git clone https://github.com/digitalbazaar/vpqr.git
cd vpqr
npm install
`

Usage

$3

`js
import vpqr from '@digitalbazaar/vpqr';

const vp = {
"@context": "https://www.w3.org/2018/credentials/v1",
"type": "VerifiablePresentation",
"verifiableCredential": {
"@context": [
"https://www.w3.org/2018/credentials/v1",
"https://w3id.org/cit/v1",
"https://w3id.org/security/suites/ed25519-2020/v1"
],
"id": "urn:uuid:188e8450-269e-11eb-b545-d3692cf35398",
"type": [
"VerifiableCredential",
"ConcealedIdTokenCredential"
],
"issuer": "did:key:z6Mku2yHBpMvm13KqtupN7MNEj7Y7AREUWsFfGBRhyP9YZf7",
"issuanceDate": "2021-03-24T20:03:03Z",
"expirationDate": "2021-06-24T20:03:03Z",
"credentialSubject": {
"concealedIdToken": "zo58FV8vqzY2ZqLT4fSaVhe7CsdBKsUikBMbKridqSyc7LceLmgWcNTeHm2gfvgjuNjrVif1G2A5EKx2eyNkSu5ZBc6gNnjF8ZkV3P8dPrX8o46SF"
},
"proof": {
"type": "Ed25519Signature2020",
"created": "2021-03-24T20:03:03Z",
"verificationMethod": "did:key:z6Mku2yHBpMvm13KqtupN7MNEj7Y7AREUWsFfGBRhyP9YZf7#z6Mku2yHBpMvm13KqtupN7MNEj7Y7AREUWsFfGBRhyP9YZf7",
"proofPurpose": "assertionMethod",
"proofValue": "z5Z33Pi9zWUWMHdxhG1Ko7ssgeHsuT3ocyg46pJTTjbwk1YjjtSCa4CQ5UyjnkQ6ar5ohY5Kv2mncWbfgEqWcVrTQ"
}
}
};

// Set up your documentLoader
const documentLoader = {/.../};
const {imageDataUrl} = await vpqr.toQrCode({vp, documentLoader});
// data:image/gif;base64,R0lGODdhqgCqAIAAAAAAAP///ywAAAAAqgCqAAAC/4yPqcvt...
`

When these QR Codes are scanned, they are read as Alphanumeric mode text,

`
VP1-R3ECQDIYBCEMDGEAYG2UADAYRCV4DA2DUORYHGOR...
`

in the format:

`

`

$3

`js
// Alphanumeric text from a QR Code Reader lib
const qrCodeText = 'VP1-R3ECQDIYBCEMDGEAYG2UADAYRCV4DA2DUORYHGOR...';

// Set up your documentLoader
const documentLoader = {/.../};

const {vp} = await vqpr.fromQrCode({text: qrCodeText, documentLoader});
// { "@context": "https://www.w3.org/2018/credentials/v1", ... }
// becomes a JSON object with the VP in the example above.
`

$3

- qrMultibaseEncoding: Encoding for QR data. B for [RFC4648][] base32, R
for [RFC9285][] base45. base45 is more efficient. Defaults to base45.
- qrErrorCorrectionLevel: Error correction level used in the QR code. 'L' Low
7%, 'M' Medium 15%, 'Q' Qartile 25%, 'H' High 30%. Defaults to 'L'.
- qrVersion: QR version. 1-40 or 0 for auto. Defaults to auto.

$3

More advanced use cases can use extra options and the lower level APIs in
util:
- Encode and decode Verifiable Credentials.
- Use custome encoding headers like VP1- and VC1-.
- Access other related outputs.
- Use options to control the output module size (the pixel size of the small
squares) and image quiet zone margin size.
- Control QR options such as error correction level.
- Provide a diagnostics function.
- Pass in legacy cborld appContextMap or modern registryEntryId,
typeTable, and typeTableLoader options.

`js
import {util} from '@digitalbazaar/vpqr';

const {toQrCode} = util;

// setup options as needed

// encode QR code
const {
version, payload, imageDataUrl, encodedCborld, rawCborldBytes
} = await toQrCode({
header: 'VC1-',
jsondldDocument: verifiableCredential,
documentLoader,
registryEntryId: 2000,
typeTableLoader,
moduleSize: 4,
margin: 16,
qrErrorCorrectionLevel: 'H'
});

// decode QR code text
const {
jsondldDocument
} = await fromQrCode({
expectedHeader = 'VC1-',
text,
decodeCborld: true,
documentLoader,
typeTableLoader
});
``

Contribute

See the contribute file!

PRs accepted.

If editing the Readme, please conform to the
standard-readme specification.

Commercial Support

Commercial support for this library is available upon request from
Digital Bazaar: support@digitalbazaar.com

License

New BSD License (3-clause) © Digital Bazaar

[RFC4648]: https://datatracker.ietf.org/doc/rfc4648/
[RFC9285]: https://datatracker.ietf.org/doc/rfc9285/