How do these work? Some alternatives: - secret key file - some kind of hashing/crypto. Something like a hash of <email>:<version1>:<yoursecrethash> and check

How do these work? Some alternatives: - secret key file - some kind of hashing/crypto. Something like a hash of <email>:<version1>:<yoursecrethash> and check against the customers keyfile. Advantage: the file doesn't need to be secret, customer will have to sign up and get a keyfile by mail. (Of course those who want to hack will just find and nop out the relevant assembly instructions) - check online for valid license (can be also be patched out easily unless you really put some effort into it) - of course there is hardware keys which again can be easily circumvented unless you put some effort into the implementation I'm leaning towards a partially-featured free version that works for all time, but I'm willing to be convinced otherwise. Disadvantages on time limited: People will find a way to reset all settings, reinstall and use it for another 14 days. Disadvantages on feature limited: Those who only need the limited feature set has it forever - those who need the extended features won't get a chance to test them. I'm leaning towards full featured, time limited. Those who want to hack it will havk it anyway.