You answer:

Short answer: I have no idea. Slightly longer answer: there will be encryption involved, and pretty high level encryption, heavy enough that the big guns would prefer not to waste their time trying to break it. Probably most apps will be based on a package simply purchased from somebody who writes this sort of code for a living. The only thing the casual programmer is likely to know about this is the name of the algorithm used, and maybe some indicator of how strong the algorithm is (how many bits in the encryption keys).