Attestation proves facts about records. Registration proves facts about data transmission.

┌────────┐         ┌─────────┐         ┌─────────┐
│        ├────────►│ Carrier │────────►│         │
│        │  issue  └─────────┘ present │         │
│        │                             │         │
│ Origin │                             │Addressee│
│        │                             │         │
│        │ submit  ┌─────────┐ deliver │         │
│        ├────────►│ Courier │────────►│         │
└────────┘         └─────────┘         └─────────┘

In Attestation, the origin issues data to a carrier, which its holder presents to an addressee. Attestation binds, authentication confirms: interaction with the carrier convinces the addressee of facts about the original records.

In Registration, the origin submits data to a courier, which ensures delivery to the addressee and registers what happened: dispatch and receipt. Either the origin or the addressee can operate the courier, but an independent courier prevents either side from unilaterally controlling the evidence.

These patterns correspond to the two trust services for sharing data across organisational boundaries: electronic attestations of attributes (EAA) and electronic registered delivery (ERD).

The proposed European Business Wallets make both accessible through a common infrastructure, together with EU-wide discovery. Many bilateral data-sharing APIs could therefore be replaced by attestations and registered delivery.