Citizens and businesses must be confident that when they interact with public authorities they are doing so in a secure and trustworthy environment and in full compliance with relevant regulations, e.g. the Regulation and Directive on data protection, and the Regulation on electronic identification and trust services (eIDAS).

Semantic interoperability ensures that the precise format and meaning of exchanged data and information is preserved and understood throughout exchanges between parties, in other words ‘what is sent is what is understood’. In the EIF, semantic interoperability covers both semantic and syntactic aspects.

A Service-oriented architecture (SOA) is essentially a collection of services. These services communicate with each other.

A Shared Infrastructure System is defined as a system that pools IT infrastructure provided by the service provider (e.g. hardware, operating system software, associated operating processes and tools) that can be physically used by several users at the time, thus being "shared".

Shared services refers to a dedicated unit (including people, processes and technologies) that is structured as a centralised point of service and is focused on providing defined business functions. These functions are supported by information technology (IT) and IT services for multiple business units within an organisation.

Developed in the context of European Union ISA programme, the Sharing and Reuse Framework for IT Solutions addresses EU, national, regional and local public administrations that aim at reducing costs, increasing their efficiency and fostering interoperability by reusing, sharing or jointly developing IT solutions that meet common requirements.

Points of Single Contact (PSCs) are e-government portals that allow service providers to get the information they need and complete administrative procedures online. 

Reference Doc: Revised EIF

The subsidiarity principle requires EU decisions to be taken as closely as possible to the citizen. In other words, the EU does not take action unless this is more effective than the same action taken at national level. The proportionality principle limits EU actions to what is necessary to achieve the objectives of the Treaties.