Thread: How to implement password access to specific file type in Linux programmatically?

1. I do not want user to launch all ".doc" files (including those he brings in).
2. User tries to launch a file "test.doc".
3. The password window appears.
4. If the password is correct, the file is opened.
Know how?..

I read this guide:
3 Ways to Create a Password Protected File on Windows 7 - wikiHow

The problem is that I want to do it by mask, not just a few known files.