how to disable a product on invalid authentication?

I'm a bit stumped at this. I have a pretty unique hashing algorithm, etc. for key/license creation; i'm not worried about that part.

what i do need ideas on is how to disable a product on invalid...er, validation.

it's on a linux platform and uses config files, etc.

i have a couple choices for action based on invalid license:

-wipe out config files (however, easily restored from backup)

-replace the binaries with non开发者_Go百科-functional binaries (but these can easily be restored from backup etc.)

-simply flag the support staff for later contact, but that still doesn't solve the problem of disallowing non-licensed copies.

ideas? i don't really have a satisfactory solution to this so far.

Whatever you do, don't mess with the to program to the point of breaking it. If your validation algorithm fails and a valid license is flagged as invalid, you have one angry paying customer who can no longer use his paid program.

I'll just display a modal window on startup that reads something along the lines:

This copy of the program has not passed the license validation. It is possible that you are running an illegal copy (maybe purchased at an unethical retailer). Please cal 1-800-whatever or send a mail to licensing@whatever.com to put a solution to this problem. If you think that you are running this program with a valid license and this message is an error on our part, contact the above phone/mail and we'll correct this.