PID: Person Identification Data

Core identity attributes in EUDI Wallet including name, birthdate, nationality, and unique identifier. PID is the foundational credential that other documents build upon.

The concept of Person Identification Data is formally defined in the eIDAS 2.0 regulation (EU 2024/1183). Article 5a establishes that the EUDI Wallet must enable users to securely request, obtain, store, and share person identification data for the purpose of identifying and authenticating online and offline.

The regulation defines PID as "a set of data enabling the identity of a natural or legal person, or a natural person representing a legal person to be established." For natural persons, this means the minimum set of identity attributes that uniquely identify a citizen across the European Union.

The PID holds a special legal status compared to other credentials in the wallet. It is the only credential type that member states are explicitly required to provide. All other credentials, such as driving licences, diplomas, or health insurance cards, are classified as electronic attestations of attributes (EAAs or QEAAs) and their issuance is at the discretion of the relevant authorities and trust service providers.

The PID must be issued at assurance level "high" as defined in the eIDAS regulation, meaning the identity proofing process must provide a high degree of confidence that the person claiming an identity is indeed that person. This typically involves in-person verification or equivalent remote verification using biometrics against existing government-held identity data.

The Architecture Reference Framework (ARF) specifies which attributes must be included in every PID credential and which are optional. This distinction matters because it determines what identity information is universally available across the EU.

Mandatory attributes: Every PID credential must contain the following core attributes. Family name (the current family name of the person). Given name (the current given name or names). Date of birth (the full date of birth in ISO 8601 format). Unique identifier (a persistent, unique, pseudonymous identifier assigned by the issuing member state that does not reveal any personal information by itself). These four attributes form the minimum viable PID that must be interoperable across all 27 member states.

Optional attributes: The PID may additionally contain: Family name at birth (maiden name). Given name at birth. Place of birth (city, country). Current address (structured or unstructured). Gender. Nationality. Age over 18 (a boolean derived attribute useful for age verification without revealing the exact date of birth). Age over N (for various age thresholds). Age in years (current age as an integer). Portrait/photo (biometric photo matching the identity document). Document number (of the underlying identity document). Administrative number (national identification number, where applicable).

Not all member states will include all optional attributes, as this depends on what data is available in each country's national identity system. For example, not all countries issue national identification numbers, and address formats vary significantly across Europe. The mandatory attributes ensure a baseline level of interoperability.

While the PID is technically a type of verifiable credential, it differs from other electronic attestations of attributes (EAAs) in several important ways.

Source of authority: The PID can only be issued by a designated government entity (the PID Provider). Other attestations can be issued by both public and private qualified trust service providers. A university can issue a diploma attestation, and a health insurer can issue an insurance card attestation, but only the designated PID Provider can issue person identification data.

Foundation for other credentials: The PID serves as the identity anchor for the entire wallet. When other issuers want to add a credential to a citizen's wallet, they typically verify the citizen's PID first. For instance, a university issuing a digital diploma will verify the student's PID to confirm they are issuing the credential to the correct person. This creates a chain of trust rooted in the government-issued identity.

Revocation implications: If a PID is revoked (for example, because the underlying physical identity document has been reported stolen or the person has passed away), the entire wallet effectively becomes unusable for identification purposes. Attestations may still be technically valid but cannot be meaningfully presented without a valid PID to establish the holder's identity.

Cross-border recognition: PIDs from all member states must be recognized across the EU by law. Attestations issued by qualified trust service providers also enjoy cross-border recognition, but non-qualified attestations may not be universally accepted.

The PID Provider is a critical actor in the EUDI Wallet ecosystem. Each member state must designate at least one PID Provider, which assumes significant responsibilities.

Identity verification: The PID Provider must verify the citizen's identity at assurance level "high" before issuing a PID. This typically involves the citizen presenting their existing physical identity document (passport, national ID card) either in person or through a certified remote identity proofing process. The PID Provider then extracts the relevant attributes and creates a signed digital credential.

Credential issuance: Using the OpenID4VCI protocol defined in the ARF, the PID Provider issues the PID credential to the citizen's wallet. The credential is cryptographically signed with the PID Provider's key and bound to the wallet's secure hardware key, preventing copying or transfer to another device.

Revocation management: The PID Provider maintains a revocation infrastructure that allows credentials to be revoked when needed, such as when an underlying identity document is invalidated, when the citizen requests revocation, or when fraud is detected. Relying parties check the revocation status as part of the verification process.

Privacy constraints: Despite its central role, the PID Provider must not be able to track when or where citizens use their PID. The issuance protocol uses techniques like batch issuance (issuing multiple copies of the credential with different cryptographic proofs) to ensure that the PID Provider cannot correlate issuance events with usage events.

One of the most powerful aspects of the PID is its cross-border interoperability. A PID issued in any EU member state must be verifiable and accepted by relying parties in all other member states.

Trusted lists: Cross-border verification relies on EU-wide trusted lists. Each member state publishes a list of its authorized PID Providers and their public keys. When a relying party in France receives a PID issued in Germany, it can look up the German PID Provider in the EU trusted list and verify the credential's signature against the provider's published public key.

Unique identifier challenge: One of the most complex aspects of cross-border PID verification is the unique identifier. Different member states use different national identification systems, and there is no single EU-wide citizen identifier. The eIDAS 2.0 regulation addresses this through Article 6a, which requires member states to ensure that the unique identifier in the PID can be matched to the person in the receiving country's system, while respecting data protection principles.

Attribute mapping: PID attributes follow a standardized schema defined in the ARF, ensuring that a "family_name" field from an Estonian PID means exactly the same thing as a "family_name" from an Italian PID. This semantic interoperability is essential for automated processing of cross-border identity verification.

Language considerations: Names in PID credentials are stored in their original form (using the script of the issuing country) and may include transliterations in Latin script. This ensures that a Greek name can be verified by a Finnish relying party even though the systems use different scripts.