Armadillo uses several public key encryption methods depending on the type and level of key you choose to use. Stronger systems resulted in longer keys.
But in all kases the encryption template is the one part that only the developer should ever know. It is the private key part of the public key encryption.
Since it can be up to 255 characters in length and can have letters, numbers, and punctuation marks in it, I always used either something randomly generated or some phrase from some fiction I had read. Encryption keys weren't passwords so you never had to memorize them, they are stored in your project's arm file and never in the protected program file so there's no way a cracker can simply find it, yet you'll always have access to it for making registration keys.
For checking registration keys, besides Armadillo's own internal public key verification, the farthest I ever went with it was that you had to be online for the initial activation so the registration key you entered could be verified against a database of keys I actually generated as a defense against key generators, after that your registration was never again checked online. It was my feeling that as long as the key never changed that there was no need to keep checking it.
This was for my own programs, not for Armadillo itself.
I can only guess that Code Factory's justification for the periodic checks is so that they can revoke a license if they discover that it was purchased using stolen credit card information.
What we did for Armadillo was to issue a temparay 30 day key at the time of the order so the customer could begin protecting and distributing his programs. After a short while, usually one week, if the purchase of Armadillo continued to look legitimate, we would then issue a permanent key that never expired.
If, after that it did turn out that the purchase was fraudulent, we'd enter the permanent key into the stolen key database and all future releases of Armadillo would reject that key.
By the way, the Armadillo trial period never expires, so feel free to tinker with it as much as you like. You will never see a trial expired message when you run Armadillo.
Also, when you are done with it and have uninstalled it. Everything that the installer copied to your system went into Armadillo's program folder.
There will be some registry entries left behind, but they were only data that the Armadillo program use and can safely be ignored.