Private FireFox plugin.

Question

I'm looking at getting a FireFox plugin developed - but is it possible to create a plugin that is for private use only, so only those I share it with have it and not open to the masses? Need this for 2 reasons; 1) while in BETA and 2) for my clients use only to start with.

Answer 1

Of course: just distribute the plugin install package (XPI if I am not mistaking) to the target users.

Note that won't prevent leaks, if any.

You could also be more fancy and "lock" the plugin to a set of computers: you have access to the whole machine when you design a plugin (e.g. NPAPI based). Then again, a determined hacker can always find a way.

Answer 2

Yes, of course this is possible.

Extensions (mentioning these because the term "plugin" is often misused to mean "extension") can be packed in a .xpi file that can be opened and installed by Firefox; see also this tutorial.

Proper plugins are a bit more work, see the Mozilla developer wiki.

Answer 3

While this works mostly on a psychological level, prominently displaying identifying information such as the user's name/email address or a company name/logo, may also help prevent users from distributing your work because it is obviously personalized/tailored software, and they may not want this information to be distributed along with your software.

Also, once you do distribute your extension to your target users, you can digitally sign the XPI files for each individual user (i.e. fingerprinting individual files within the XPI package), so that you can track back any leaks.

In addition, you as the author of the extension are of course free to implement a simple "talkback" mechanism so that you can track use of your extension, along with all sorts of other information that may be relevant to you (i.e. usage stats).

Similarly, XPI files are conventional ZIP files, so you can also password-protect them to make it more complicated to install them without proper instructions.