design "product keys"

I have a software that I would like to have product keys to register the software.

These product keys will be used only once, and will tell the machine limits that the customer can create in the program.
anyone have an idea how to do these or the software to do this?


Thanks,
Daniel

Just make a good random number generator and store the values to your database. Then check against that. That works if you're registering online.

If you don't have online registration, you run into the problem of people being able to share codes between each other.

Programs that use an equation to generate the code often get cracked and you'll see small programs that generate a unique number for your computer.

One simple method I use to generate random numbers is to use a large file (iso images work for this) and xor the bytes against themselfs over an array. Then xor rand() to finish it off

ie:
key[0x0FFFFF] (1Meg of keys)
pos=file position

key[pos&0x0FFFFF]=key[pos&0x0FFFFF]^nextByteFromFile^rand()

I'm new at this, and I am planning on having it activate online, if thats easier. Do you know any sample programs that I could look at, and view sample codes on how to do something like this because I don't know a thing about it.

Thanks,
Daniel T.

Nope, sorry, never had to write software that needs to be registered. All my stuff is in-house.

I just know how to make a bunch of unique number because we use them for encryption of data.

you're talking about shareware key generation. Try to search shareware resource for this. I wrote my own key generator. I know some shareware registration company offers online key generation service