Enter e-Estonia: interoperability — e-Estonia
To build Estonia’s digital society, it was not feasible to allow each government agency to ask for and store the user’s data. Such data duplication would make these agencies more susceptible to coordinated cyber attacks, as well as make it difficult to keep an individual’s information up-to-date. The solution to this was Estonia’s adoption of the “once-only principle,” whereby the user’s data is effectively divided up amongst the different agencies. This means information such as the user’s address can only be asked for and stored by one authority, in this case the population registry.