On 5/6/11 4:41 AM, Jerry Foote wrote: > I would appreciate opinions as to the best copy protection scheme for a > general distribution program.
I allow my software and application data to be freely copied (make it easy for paid customers to do what they want). But there's a license file in the appdata directory that: 1) must be present for the application to start (if not, a screen prompts for the license, directing the user to the web page to purchase a key) 2) the applications checks the status of upon each app start, but if the computer is offline it allows a max. of 20 days to pass before saying "go online so I can check the validity of your license". 3) uses information coded in the license file to generate the company name, city, state, and phone number fields. This information, from the license, is what gets shown on screens, in reports, etc. So you can't just copy another user's license unless you want to represent yourself as that user. You also can't change the values in the (plain-text) license file because the software looks at the hash and compares it with the encrypted hash in the same plain text file. Change one character in the license file, and it is no longer valid. We control the validity of each license on our servers, and can turn them off and on at will. In our case this software is free to customers above a certain purchase volume that are in good standing. If they are late on a payment we've found that invalidating their license results in a check going into the mail immediately. I don't think anyone's yet figured out that they could last 20 days on a bad license by just unplugging the internet when the app starts. Paul _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://leafe.com/mailman/listinfo/profox OT-free version of this list: http://leafe.com/mailman/listinfo/profoxtech Searchable Archive: http://leafe.com/archives/search/profox This message: http://leafe.com/archives/byMID/profox/[email protected] ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
