Editing Schengen Information System (section)

== Legal aspects and technical characteristics ==
SIS was created to maintain European security after 25 March 2001 when border security between fifteen nations was relaxed. The SIS requires Schengen nations to respect the legal force of the information it contains. It also requires the nations to respect the privacy and personal freedom of the people whose data is held according to national data laws. SIS's information processing system must be permanently connected to member nations' databases and must be updated in [[real-time computing|real-time]].

These commitments are supplemented by consultation procedures between the member nations. Discussions may take place about issues such as confirmation of information, variation of actions directed by SIS, questions of residency, and international warrants for arrest.

SIS is controlled by an authority composed of representatives of the member nations. Personal data protection is a key responsibility. At a technical level, the participating countries adopted a data-processing star architecture made up of a central site containing the reference database, known as C-SIS, for which the responsibility is entrusted to the French Republic by the CAAS, and a site by country, known as N-SIS, containing a copy of the database.