@digitalbazaar/vpqr
v5.1.0
Published
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.
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Readme
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
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
Encoding Verifiable Presentations as QR Code Images
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:
<format and version, 'VP1-'><multibase prefix, 'R'><base45 RFC9285 encoded CBOR-LD>
Decoding QR Code Text to Verifiable Presentation
// 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.
Encoding Options
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.
Advanced Options
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-
andVC1-
. - 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 modernregistryEntryId
,typeTable
, andtypeTableLoader
options.
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: [email protected]
License
New BSD License (3-clause) © Digital Bazaar