Serial Key Gen and registration for shareware

[login to view URL] to have serial key and key generator created as well as a way to clear these for testing purposes for a shareware program I distribute. I can only use something that is 64 bit symetric encryption or less or some other way to do this would be acceptable if it was secure. It needs to be something that I can periodically change myself, re-defining the algorithm to keep the crackers busy. So please comment heavy & I will be able to understand what you have done and what I need to do to change anything. I would want the user to have a 30 day trial period, and something that looks similar to what I have now. ( Successful coder will receive the form that I am currently using ) No rollbacks should be allowed..right now they can roll it back, and that's definitely not working for me. I also have the paypal registration link directly on the registration form, and need to keep this. 2.I need to create two versions of this. One so that the user can automatically get it as a download from my website ( I have mysql database,+ php4) as well as my manually generating the key. Just in case I need to take a vacation and don't want to be tied to a pc for a week. Coder will provide the necessary information and I will test it on my website. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Complete ownership and distribution copyrights to all work purchased. 3) I need this by July 5 2003 or sooner. Please do not bid if you cannot complete it by this date. ## Platform vb6 windows 98 Me xp 2000