Re: [2005] Leak Protection
Having done this kind of thing a few times, I would actually recommend using a third party licensing tool. These feature hardware locks, time limits and execution based limits, license extensions etc.
If you implement something yourself, you will have to confront all the same issues that commercial licensing systems solve. It's a lot of work and I think it's one of these occasions where a commercial solution makes sense.
Licensing over the web has it's own problems. If you transmit data over http, it's insecure. It'a slso possible to create a website that 'impersonates' your own site.
Your executable can be reverse engineered, which gives a hacker a representation of your software. That in turn exposes any defences you may have built in. So obfuscation is a useful defence, but nothing is ever 100% secure. You just need to raise the bar high enough so that hackers give up and move onto something easier.
Tools such QLM http://www.interactive-studios.net/products/qlm.htm or ExeShield http://www.exeshield.com/ are very good for this. QLM is not very expensive, ExeShield features obfuscation but is expensive. At the end of the day it all depends on how valuable your application is to you.
Re: [2005] Leak Protection
Awesome. Thanks for the links, I'll test them out. :)