WP users and plugins

I am wondering if there is a way to allow someone to login and use a plugin’s functionality without revealing the source code through plugin editor. The plugin I am writing allows a user to alter the_content based on user selections. I ask because I would like to demo this plugin in the near future but my data represents a lot of mining and I would not be happy for someone to steal it before the release. I’m sure it will happen on first release, but would like to beta without direct access.