Schengen Information System, also known as SIS, is a computer system used in a number of European countries that records personal information on people who have been arrested, migrants, and missing objects. This information is shared among its users, signatories of the Schengen treaty, which includes the countries of France, Germany, Belgium, the Netherlands and Luxembourg. Since its formation, several other European nations have joined the system, including Austria, Iceland and Finland.

In SIS information is stored about persons who are suspected of having performed or witness crimes and those who may perform or witness crimes in the future. It has over a million individual entries, containing such information as name, profession, political views and sexual orientation. It has been the target of a number of protests over invasion of privacy, including a protest camp of 2,000 No Border network activists from July 18 to July 28, 2002 in Strasbourg, France, where the SIS is located, A second, more complex version is being planned, which could include fingerprints, photographs, and DNA profiles, to handle the increased volume of data and proliferation of access points. A person's SIS file can be accessed by hand-held computers across Europe, and is accessible to all levels of police and border officials when conducting routine checks of personal documentation.

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