An eID server is a hardware and software component that enables service providers to integrate the eID function into their IT systems. It handles the secure communication that takes place between eID clients, the chips on users' eID cards, and eID applications. To perform its checks (on eID cards and eID applications), a server of this kind retrieves new authorisation certificates and updated certificate revocation lists from an authorisation certificate provider on a regular basis.

In many cases, service providers do not operate their own eID servers. Instead, they connect to the eID infrastructure via another service provider that runs a multi-client-capable eID server. This latter type of entity is referred to as an eID server provider.

Framework conditions

The technical basis for eID servers is provided by the functional specification found in part one of Technical Guideline BSI TR-03130. Part four describes the tests that can be performed to determine the extent to which eID servers conform to this specification. This conformity ensures their interoperability with other eID components.

To facilitate such tests, a tool called eID-Client-Testbed was created on behalf of the BSI. This open-source program is available free of charge in the GitHub repository eID-Testbeds.

Test and development system

Every eID server provider is advised to provide a test element of its eID server or eID service. This test element will improve the functionality of the server or service and its interoperability with other components of the eID infrastructure.

Active system

At present, eID servers are only offered by commercial providers. A list of all the certified eID servers can be found on the BSI website under Certified Products -- eID Servers. In addition, the National ID Card Portal provides overviews of the providers of eID servers and eID service providers.