We offer two different key "formats" for Boxcryptor with two different goals:
Product key: 8 groups of 8 characters ("looks like a Windows product key"). A product key can used to upgrade a free Boxcryptor account to an Unlimited Boxcryptor account.
License key: Is more complicated and has the "LICENSE KEY" header ("looks like a PGP key"). A license key can be used to unlock the Unlimited features on a local account.
So if you're using a local account, a product key does not help you very much as it can only be used with a Boxcryptor account. But it's not a big problem. If you can please send a mail to firstname.lastname@example.org with your purchase details we will create a license key which you can use with your local account.