Verifiable Credentials (VCs)

Verifiable Credentials are a W3C standard for expressing credentials in a way that is cryptographically secure, privacy-respecting, and machine-verifiable. They enable trusted digital claims about subjects.

Verifiable Credential Data Model

LearnCard implements the W3C Verifiable Credentials Data Model, with support for both VC 1.0 and VC 2.0 formats. The core data types are defined using Zod validators.

Credential Structure

Component	Description	Required
@context	JSON-LD contexts defining the vocabulary	Yes
id	Unique identifier for the credential	No
type	Array of credential types	Yes
issuer	Entity that issued the credential	Yes
credentialSubject	Entity the credential is about	Yes
proof	Cryptographic proof of authenticity	Yes

Version differences:

• VC 1.0 uses issuanceDate and expirationDate

• VC 2.0 uses validFrom and validUntil

https://github.com/learningeconomy/LearnCard/blob/942bb5f7/packages/learn-card-types/src/vc.ts#L129-L177

export const UnsignedVCValidator = z
    .object({
        '@context': ContextValidator,
        id: z.string().optional(),
        type: z.string().array().nonempty(),
        issuer: ProfileValidator,
        credentialSubject: CredentialSubjectValidator.or(CredentialSubjectValidator.array()),
        refreshService: RefreshServiceValidator.or(RefreshServiceValidator.array()).optional(),
        credentialSchema: CredentialSchemaValidator.or(
            CredentialSchemaValidator.array()
        ).optional(),

        // V1
        issuanceDate: z.string().optional(),
        expirationDate: z.string().optional(),
        credentialStatus: CredentialStatusValidator.or(
            CredentialStatusValidator.array()
        ).optional(),

        // V2
        name: z.string().optional(),
        description: z.string().optional(),
        validFrom: z.string().optional(),
        validUntil: z.string().optional(),
        status: CredentialStatusValidator.or(CredentialStatusValidator.array()).optional(),
        termsOfUse: TermsOfUseValidator.or(TermsOfUseValidator.array()).optional(),
        evidence: VC2EvidenceValidator.or(VC2EvidenceValidator.array()).optional(),
    })
    .catchall(z.any());
export type UnsignedVC = z.infer<typeof UnsignedVCValidator>;

export const ProofValidator = z
    .object({
        type: z.string(),
        created: z.string(),
        challenge: z.string().optional(),
        domain: z.string().optional(),
        nonce: z.string().optional(),
        proofPurpose: z.string(),
        verificationMethod: z.string(),
        jws: z.string().optional(),
    })
    .catchall(z.any());
export type Proof = z.infer<typeof ProofValidator>;

export const VCValidator = UnsignedVCValidator.extend({
    proof: ProofValidator.or(ProofValidator.array()),
});
export type VC = z.infer<typeof VCValidator>;

Verifiable Presentations (VPs)

Verifiable Presentations allow holders to bundle and selectively disclose credentials: