The collective file format is a crossplatform format. If you want to build for PC from the mac you may, just be careful not to include any platform specific binaries. Then you get all the externals you need for the other platform and a user may run the collective using the runtime or whatever.
The collective file format is in no way "secure", and was never intended to be. It is trivial to extract Max patches from a collective and at some point we may even make the details of the format public. Until then, you can just open them up in a text editor and have a look yourself.
There have been a number of requests for various C74 created ways to encrypt Max patches over the years and generally our feeling is that we will not do it. Writing CP code is a fairly boring and unrewarding way to spend your life. We use a third party for our CP needs, and would prefer to spend our development resources on new features for users rather than running around trying to stay one step ahead of the h20s of the world.We encourage people who have algorithms they would like to protect to do the same thing.
There is absolutely no "security" whatsoever in the collective file format , and we have never represented as much. If someone knows what they are doing, they can pretty much have it all, patches, externals, the lot.
If you have algorithms you need to protect, you should do it with purpose built tools.