DE4A Common Components

This section provides an overview of the common components and specifications required for the evidence exchanges. A high-level conceptual diagram of the envisaged infrastructure, containing the main software components required for the first iteration of the pilots, is presented below.

The following table describes the common components in the above diagram, leaving out those components that are developed or deployed directly by each DE4A participant, namely the Data Evaluator, the Data Owner and the eIDAS Nodes.

Component	Description
DE4A Connector	Technical proxy that allows the final participants to send requests for evidence or responses to other final participants over an eDelivery communication environment
SML	The Service Metadata Locator. Reference instance in the DE4A network
SMP	Service Metadata Publisher
AS4 Gateway	AS4 protocol implementation for the message exchange
Mocked IDK	Testing component for the IAL definition
SSI Authority Agent	Enterprise-level solution that enables issuing and submitting diplomas in the form of verifiable credentials/presentations to Issuers/Verifiers.
SSI Edge Agent	Mobile digital wallet solution that enables users to manage their digital diplomas and interact with the Issuer's/Verifier's portals.

Common specifications

Third party specifications and components

List and description of the third party libraries and components that have allowed to build the DE4A components faster and extensibles, increasing the stability and robustness.

Description of common software interfaces

REST APIs interfaces reference for most of the components involved in the message exchanging.

DE4A Logs and error messages

Definition and reference of the error coding and logs handling. Includes an standarised log and error messages within the DE4A project to provide a well understanding among the different components regarding their points of failure and and the different states in which each system is placed.