It also depends on how your license algorithm works. I'd suggest you look into using something like a Diffie–Hellman key exchange (or even RSA) to generate some sort of public/private key that can be passed to your users, based on some information.
(Depending on the application, I know of one case where I wrote the license code on contract for a company, they used a MAC address, and some other data, hashed it, and encrypted the hash, giving them the "key value", if the registration number was correct). This ensures that the key file can't be moved, (or given) to another machine, thus 'stealing' the software.
If you want to dig deeper and avoid hackers, that's a whole 'nother topic....
