I'm working on a solution to be distributed online and thinking about how to protect it. Would you coment on it? I'm using a one licence per client.
- I'm using a layout "MAC" that is only visible to the developer and a table that is only accessable to the developer.
- It contains a field that holds the computers MAC address
- A calculation processes the hexadecimal value into a decimal value (to obfuscate the origin).
- In another Layout "Licence" I'm displaying this decimal number and the user is asked to send it to me when paying the software.
- I do have a password database which can calculate the original MAC adress of that user and store it. It also calculates (with some magic substractions, multiplications and divisions) a Serial Number, which I send in reply. The user has to enter this serial number. When the serial number (reversing the magic substraction, multiplications and divisions) matches the MAC address, the license is valid.
I'm aware that I'll have users who replace their computers and subsequently call me, because their license becomes invalid. This may also occur if they would change certain parts, e.g. the network card, which leads to a change in the MAC address.
A bigger difficulty seems to me the automation of the shopping process. At the moment I do not see any other option than receiving the calculated number by email or so, putting it in my database and replying by email. Which could take up to 24 hours or more (if I'm on holiday). I do not expect tons of people buying the solution... Maybe 100. I'm not expecting the thing such a success, that people would actively start to crack it or so. (Otherwise I would want ot discuss it here...)
Do you know of any online selling services for software that might deal with this process of exchanging the serial?
Any other comments or hints?