(Likely to be answered by the community's more advanced programmers)

**Disclaimer - I am by no means trying to hack historical files. I am interested in a broad overview of security options available to protect intellectual property in the event that an employee is terminated or resigns.**

At a past employer, I accessed a website to pass security credentials and be granted a 24-numerical digit temporary license. I then copy/pasted this into a dialog box at workbook initialization. If TRUE, workbook opened and was fully functional; if FALSE or NOTHING, workbook remained open, but was greyed out and inaccessible.

1) - What was going on behind the scenes under this method of security? How did excel know that the entered license number was valid? WebServices call?

2) - We have several web-based applications that verify users against the active directory before granting access. Can similar security be implemented in excel? How big of a scope would a project like this be were I to contract out?

3) Is method 2 preferred to method 1. Is there another more preferable way not mentioned?

Thanks!