Modern software engineering trends towards Cloud-native software development by international teams of developers. Cloud-based version management services, such as GitHub, are used for the source code and other artifacts created during the development process. However, using such a service usually means that every developer has access to all data stored on the platform. Particularly, if the developers belong to different companies or organizations, it would be desirable for sensitive files to be encrypted in such a way that these can only be decrypted again by a group of previously defined people. In this paper, we examine currently available tools that address this problem, but which have certain shortcomings. We then present our own solution, Encrypted Container Files (ECF), for this problem, eliminating the deficiencies found in the other tools.