Credential Formats

BaseID supports three credential formats, each suited to different use cases and regulatory requirements.

Format Comparison

Feature	W3C VC (JWT)	SD-JWT VC	ISO mDL (mdoc)
Encoding	JSON / JWT	JSON / JWT	CBOR
Selective Disclosure	No (full reveal)	Yes (per-claim)	Yes (per-element)
Size	Medium	Medium	Small (binary)
eIDAS 2.0	Supported	Mandated	Mandated
Crate	baseid-vc	baseid-sd-jwt	baseid-mdl
Standard	W3C VC Data Model 2.0	IETF SD-JWT VC	ISO/IEC 18013-5

W3C Verifiable Credentials (JWT-VC)

The most widely adopted format. Credentials are JSON objects signed as JWTs. Simple to implement and broadly interoperable.

use baseid_vc::{sign_credential_jwt, verify_credential_jwt};

Best for: general-purpose credentials, interoperability with existing systems.

SD-JWT Verifiable Credentials

Extends JWT-VC with selective disclosure. The holder can reveal only specific claims to a verifier, preserving privacy.

use baseid_sd_jwt::{SdJwtIssuer, SdJwtHolder, SdJwtVerifier};

Best for: privacy-sensitive credentials, eIDAS 2.0 compliance, government-issued identity.

ISO mDL (mdoc)

Binary CBOR-based format designed for mobile driving licences. Compact, efficient, and supports both online and offline verification.

use baseid_mdl::{MdlIssuer, MdlVerifier};

Best for: driving licences, government ID, offline verification, constrained environments.

Choosing a Format

• Start with JWT-VC if you need broad compatibility
• Use SD-JWT when privacy and selective disclosure matter
• Use mDL for driving licences or when binary efficiency is required
• For eIDAS 2.0 compliance, you will need both SD-JWT and mDL