Wiki for CrypTool 2 developers: https://www.cryptool.org/trac/CrypTool2/wiki/WikiStart
Contact between CrypTool 2 developers: https://www.cryptool.org/trac/CrypTool2/wiki/DiscussionGroups
Access to the CrypTool 2 source code:
URL: https://www.cryptool.org/svn/CrypTool2
User: anonymous
Pass: No password required
The source code can be accessed anonymously. Ideally, you should use an SVN client like TortoiseSVN
Please be aware that we only allow write access for people who have proven to develop source code at an acceptable quality level and on a longer term basis. You are most welcome to get in touch with us and discuss further details.
HowTo for plugin development: Download
Plugin template for Visual Studio: Download

