This is a tricky one and it depends on the size of the code base you are trying to protect. Here are a couple of things you can try. 1. If the code represents a platform, and if the team is large enough you can segment the codebase into multiple repositories and then segment access to them e.g. repositories for the presentation tier (gui interfaces) and repos for services so no one in the team has access to the full set of code. 2. You can achieve similar things to the above by having "core" code e.g base and common classes which are compiled and provided as compiled assemblies to the rest of the team. This way they never work with the deep internals of the system. 3. If you are working with applications you can look into locking them down with code signing certificates. This not prevent the source code but it will prevent the team from taking the code and repackaging it for sale as they won't have the certificates. 4. If you are really paranoid, consider getting all developers to remote into a terminal services environment (or similar) for development, this prevents the ability for the developer to copy large number of coding files off the development environment. Hope this helps a little.
