Thousands of hackers gathered in the eastern German city of Leipzig which hosts this year's Chaos Communication Congress.
The congress, held from Dec. 27 to 30, is organized by the Chaos Computer Club (CCC) — Europe's largest association of hackers.
The Europe's largest meeting of hackers is expected to attract some 15,000 information technology experts, 3,000 more than last year.
At the congress, the speakers and participants will discuss the weak points of computer technology and internet applications, wiretapping and information protection issues.
The congresses usually include a wide range of activities, including specialist assemblies, various challenges, displays and discussions.