@dwn-protocol/id-sdk
Version:
SDK for accessing the features and capabilities
225 lines • 9.9 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.createJwt = exports.decodeJwt = exports.validatePayload = exports.VerifiableCredential = exports.VC_DATA_FORMAT = exports.DEFAULT_VC_TYPE = exports.DEFAULT_CONTEXT = void 0;
const uuid_1 = require("uuid");
const utils_js_1 = require("./utils.js");
const index_js_1 = require("../common/index.js");
const did_jwt_1 = require("did-jwt");
const index_js_2 = require("../dids/index.js");
const validators_js_1 = require("./validators.js");
exports.DEFAULT_CONTEXT = 'https://www.w3.org/2018/credentials/v1';
exports.DEFAULT_VC_TYPE = 'VerifiableCredential';
exports.VC_DATA_FORMAT = 'application/vc+jwt';
const didResolver = new index_js_2.DidResolver({ didResolvers: [index_js_2.DidIonMethod, index_js_2.DidKeyMethod, index_js_2.DidDhtMethod] });
class DwnResolver {
async resolve(didUrl) {
return await didResolver.resolve(didUrl); // DIDResolutionResult
}
}
const dwnResolver = new DwnResolver();
/**
* `VerifiableCredential` represents a digital verifiable credential according to the
* [W3C Verifiable Credentials Data Model](https://www.w3.org/TR/vc-data-model/).
*
* It provides functionalities to sign, verify, and create credentials, offering a concise API to
* work with JWT representations of verifiable credentials and ensuring that the signatures
* and claims within those JWTs can be validated.
*
* @property vcDataModel The [VcDataModel] instance representing the core data model of a verifiable credential.
*/
class VerifiableCredential {
constructor(vcDataModel) {
this.vcDataModel = vcDataModel;
}
get type() {
return this.vcDataModel.type[this.vcDataModel.type.length - 1];
}
get issuer() {
return this.vcDataModel.issuer.toString();
}
get subject() {
if (Array.isArray(this.vcDataModel.credentialSubject)) {
return this.vcDataModel.credentialSubject[0].id;
}
else {
return this.vcDataModel.credentialSubject.id;
}
}
/**
* Sign a verifiable credential using [signOptions]
*
*
* @param signOptions The sign options used to sign the credential.
* @return The JWT representing the signed verifiable credential.
*
* Example:
* ```
* const signedVc = verifiableCredential.sign(signOptions)
* ```
*/
// TODO: Refactor to look like: sign(did: Did, assertionMethodId?: string)
async sign(signOptions) {
const vcJwt = await createJwt({ vc: this.vcDataModel }, signOptions);
return vcJwt;
}
/**
* Converts the current object to its JSON representation.
*
* @return The JSON representation of the object.
*/
toString() {
return JSON.stringify(this.vcDataModel);
}
/**
* Create a [VerifiableCredential] based on the provided parameters.
*
* @param vcCreateOptions The options to use when creating the Verifiable Credential.
* @return A [VerifiableCredential] instance.
*
* Example:
* ```
* const vc = VerifiableCredential.create({
* issuer: 'did:ex:issuer',
* subject: 'did:ex:subject',
* data: { 'arbitrary': 'data' }
* type: 'ChiaCredential',
* })
* ```
*/
static create(vcCreateOptions) {
const { type, issuer, subject, data, issuanceDate, expirationDate, revocable, suspendable, statusListCredentialId } = vcCreateOptions;
const jsonData = JSON.parse(JSON.stringify(data));
if (typeof jsonData !== 'object') {
throw new Error('Expected data to be parseable into a JSON object');
}
if (!issuer || !subject) {
throw new Error('Issuer and subject must be defined');
}
const credentialSubject = Object.assign({ id: subject }, jsonData);
const vcDataModel = Object.assign({ '@context': [exports.DEFAULT_CONTEXT], type: Array.isArray(type)
? [exports.DEFAULT_VC_TYPE, ...type]
: (type ? [exports.DEFAULT_VC_TYPE, type] : [exports.DEFAULT_VC_TYPE]), id: `urn:uuid:${(0, uuid_1.v4)()}`, issuer: issuer, issuanceDate: issuanceDate || (0, utils_js_1.getCurrentXmlSchema112Timestamp)(), credentialSubject: credentialSubject }, (expirationDate && { expirationDate }));
// Note: credentialStatus is added by StatusListManager.addCredentialStatus()
// This is handled at a higher level when creating revocable credentials
// The revocable/suspendable flags are stored here for reference but
// actual credentialStatus linking happens via VcApi.createRevocableCredential()
validatePayload(vcDataModel);
return new VerifiableCredential(vcDataModel);
}
/**
* Verifies the integrity and authenticity of a Verifiable Credential (VC) encoded as a JSON Web Token (JWT).
*
* This function performs several crucial validation steps to ensure the trustworthiness of the provided VC:
* - Parses and validates the structure of the JWT.
* - Ensures the presence of critical header elements `alg` and `kid` in the JWT header.
* - Resolves the Decentralized Identifier (DID) and retrieves the associated DID Document.
* - Validates the DID and establishes a set of valid verification method IDs.
* - Identifies the correct Verification Method from the DID Document based on the `kid` parameter.
* - Verifies the JWT's signature using the public key associated with the Verification Method.
*
* If any of these steps fail, the function will throw a [Error] with a message indicating the nature of the failure.
*
* @param vcJwt The Verifiable Credential in JWT format as a [string].
* @throws Error if the verification fails at any step, providing a message with failure details.
* @throws Error if critical JWT header elements are absent.
*
* ### Example:
* ```
* try {
* VerifiableCredential.verify(signedVcJwt)
* console.log("VC Verification successful!")
* } catch (e: Error) {
* console.log("VC Verification failed: ${e.message}")
* }
* ```
*/
static async verify(vcJwt) {
const jwt = decodeJwt(vcJwt); // Parse and validate JWT
// Ensure the presence of critical header elements `alg` and `kid`
if (!jwt.header.alg || !jwt.header.kid) {
throw new Error('Signature verification failed: Expected JWS header to contain alg and kid');
}
const verificationResponse = await (0, did_jwt_1.verifyJWT)(vcJwt, {
resolver: dwnResolver
});
if (!verificationResponse.verified) {
throw new Error('VC JWT could not be verified. Reason: ' + JSON.stringify(verificationResponse));
}
}
/**
* Parses a JWT into a [VerifiableCredential] instance.
*
* @param vcJwt The verifiable credential JWT as a [String].
* @return A [VerifiableCredential] instance derived from the JWT.
*
* Example:
* ```
* val vc = VerifiableCredential.parseJwt(signedVcJwt)
* ```
*/
static parseJwt(vcJwt) {
const decodedVcJwt = decodeJwt(vcJwt);
const vcDataModel = decodedVcJwt.payload.vc;
if (!vcDataModel) {
throw Error('Jwt payload missing vc property');
}
return new VerifiableCredential(vcDataModel);
}
}
exports.VerifiableCredential = VerifiableCredential;
/**
* Validates the structure and integrity of a Verifiable Credential payload.
*
* @param vc - The Verifiable Credential object to validate.
* @throws Error if any validation check fails.
*/
function validatePayload(vc) {
validators_js_1.VcValidator.validateContext(vc['@context']);
validators_js_1.VcValidator.validateVcType(vc.type);
validators_js_1.VcValidator.validateCredentialSubject(vc.credentialSubject);
if (vc.issuanceDate)
validators_js_1.VcValidator.validateTimestamp(vc.issuanceDate);
if (vc.expirationDate)
validators_js_1.VcValidator.validateTimestamp(vc.expirationDate);
}
exports.validatePayload = validatePayload;
/**
* Decodes a VC JWT into its constituent parts: header, payload, and signature.
*
* @param jwt - The JWT string to decode.
* @returns An object containing the decoded header, payload, and signature.
*/
function decodeJwt(jwt) {
const [encodedHeader, encodedPayload, encodedSignature] = jwt.split('.');
if (!encodedHeader || !encodedPayload || !encodedSignature) {
throw Error('Not a valid jwt');
}
return {
header: index_js_1.Convert.base64Url(encodedHeader).toObject(),
payload: index_js_1.Convert.base64Url(encodedPayload).toObject(),
signature: encodedSignature
};
}
exports.decodeJwt = decodeJwt;
/**
* Create a VC JWT.
*
* @param payload - the payload for the JWT.
* @param signOptions The sign options used to sign the credential.
* @return The JWT representing the signed verifiable credential.
*/
async function createJwt(payload, signOptions) {
const { issuerDid, subjectDid, signer, kid } = signOptions;
const header = { alg: 'EdDSA', typ: 'JWT', kid: kid };
const jwtPayload = Object.assign({ iss: issuerDid, sub: subjectDid }, payload);
const encodedHeader = index_js_1.Convert.object(header).toBase64Url();
const encodedPayload = index_js_1.Convert.object(jwtPayload).toBase64Url();
const message = encodedHeader + '.' + encodedPayload;
const messageBytes = index_js_1.Convert.string(message).toUint8Array();
const signature = await signer(messageBytes);
const encodedSignature = index_js_1.Convert.uint8Array(signature).toBase64Url();
const jwt = message + '.' + encodedSignature;
return jwt;
}
exports.createJwt = createJwt;
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