The Computer Center of the Faculty of Mathematics endorses free and open software, as well as a healthy privacy and security culture online. Four easy steps for privacy/security and against mass surveillance are:
Good instructions and a lot more software for privacy and against mass surveillance can be found here:
Lectures about Security and Privacy are also held by the ZID and are announced on their course-offering-page.
Mathematics and mathematicians (and of course computer scientists and programmers) play a particularly important role when it comes to mass surveillance. Some discussion is ongoing in the AMS Notices, the LMS Newsletter, and math blogs like the n-Category Cafe. See the post "Math and Mass Surveillance: A Roundup" for a partial summary.
For further information about the following points please visit the ZID homepage (only available in German):