EUDI Wallet and digital identity glossary
This glossary explains the terms a relying-party team encounters when integrating European Digital Identity (EUDI) Wallet presentations. It focuses on the roles, credentials, formats, protocols, and trust material used in verification. A term can have a narrower legal or profile-specific meaning in a regulation or technical specification; follow the referenced source when implementing a particular profile.
Ecosystem and roles
EUDI Wallet
The European Digital Identity Wallet is an electronic identification means that lets a user securely store, manage, and validate person identification data and electronic attestations of attributes, present them to relying parties or other wallet users, and use qualified electronic signatures or seals. It is an ecosystem of wallet units and participants, not one EU-operated app. See the EUDI Wallet overview.
Holder
The person or entity that holds credentials in a wallet and chooses whether to present them. A presentation is made for a particular interaction with a verifier.
Issuer
An organization that creates and issues a credential, making claims about a subject. Issuers and the organizations that operate wallets are separate roles, even when a deployment has relationships between them.
Relying party (RP) / verifier
The service that requests a presentation and validates it before applying its own access, onboarding, or eligibility policy. A verifier's successful cryptographic checks do not by themselves decide whether a person qualifies for a service.
Subject
The person, organization, or thing that the credential's attributes describe. The holder and subject are often the same person, but implementations should not assume that relationship without checking the credential profile.
Credentials and evidence
PID — person identification data
Person identification data is a defined set of data that represents a natural person and enables that person to be identified. A PID credential is distinct from an arbitrary collection of identity attributes and is governed by the applicable EUDI Wallet profile. See the PID Rulebook in the Architecture and Reference Framework.
Attribute
A characteristic, quality, right, or permission of a natural person, legal person, or object. Examples include a date of birth, an entitlement, or a licence category.
EAA — electronic attestation of attributes
An electronic attestation is data in electronic form that allows attributes to be authenticated. An EAA can convey attributes beyond the core person identification data, depending on its issuer and profile.
QEAA — qualified electronic attestation of attributes
A qualified EAA is issued by a qualified trust service provider and meets the requirements set out in the eIDAS framework. “Qualified” is a legal status with specific requirements; it is not a synonym for any signed or digitally verifiable credential.
Credential
A set of claims about a subject made by an issuer. In wallet implementations, credentials may use different data models, encodings, and cryptographic mechanisms. A verifier must process the format and profile it actually supports.
Presentation
Data derived from one or more credentials and shared with a particular verifier. A presentation is transaction-specific evidence; it is not necessarily the original credential in full.
Selective disclosure
A capability to disclose selected credential data instead of sharing every field. What can be selectively disclosed depends on the credential format, issuer profile, wallet, and verifier request. Do not assume every credential format supports the same disclosure behavior.
Predicate
A request for an assertion that a condition is true, such as being at least 18, without necessarily asking for the underlying value such as a full date of birth. Whether a predicate can be answered without disclosing the source value depends on the credential and presentation profile. See EUDI Wallet age verification.
Protocols and formats
OID4VP — OpenID for Verifiable Presentations
An OpenID Foundation protocol for requesting and presenting credentials. It defines the presentation exchange framework, while credential formats and deployment profiles specify additional request fields and validation rules. OID4VP does not decide which issuers a relying party trusts. Continue with the OID4VP overview and the OID4VP integration guide.
mdoc
A mobile document format used for digital versions of identity documents. The ISO mdoc ecosystem defines document and presentation mechanisms; an implementation must support the relevant document type and profile. DLBR's mdoc verification guide describes the supported verification path.
mDL — mobile driving licence
A mobile driving licence is a digital driving-licence credential using the mobile-document ecosystem. “mDL” names a credential use case; “mdoc” names a format family. They are related terms, but not interchangeable.
SD-JWT
Selective Disclosure JSON Web Token is a format for selectively disclosable claims represented with JSON Web Tokens. Its disclosure and key-binding checks differ from the mdoc presentation flow. See SD-JWT verification and the SD-JWT vs mdoc comparison.
OIDC — OpenID Connect
An identity layer on OAuth 2.0 commonly used for user authentication and identity claims. OIDC and OID4VP share OpenID and OAuth building blocks, but serve different purposes: authentication and identity claims versus credential presentation. See OID4VP vs OpenID Connect.
Trust and transaction terms
Trust anchor
A configured public key or certificate at the root of a verifier's trust decision. A verifier uses its trust policy and validation procedure to decide whether an issuer or certificate chain is acceptable for the requested purpose. A valid signature alone does not establish that an issuer is trusted.
Nonce
A fresh, transaction-specific value used by a protocol profile to bind a cryptographic response to the verifier's request and reduce replay risk. A verifier should validate it against the value issued for that transaction. See OID4VP nonce and state validation.
State
An opaque value commonly used to correlate an authorization response with the verifier's local transaction. It is application correlation data and does not replace cryptographic nonce or holder-binding checks.
WRPAC and WRPRC
Wallet-Relying Party Access Certificate (WRPAC) and Wallet-Relying Party Registration Certificate (WRPRC) are registration-related artifacts used in the EUDI Testing Relying Party environment and supported integration workflow. They are not generic names for every verifier's production trust material. See the EUDI integration checklist.
ARF — Architecture and Reference Framework
The EUDI Wallet Architecture and Reference Framework describes architecture and technical specifications for the ecosystem. It provides a common reference, while specific use cases and releases can define their own requirements. Consult the current ARF documentation alongside the regulations and profile specifications relevant to a deployment.