I can't speak to CB. Over the years CB (11 meter) has become a rather outlaw channel. It use to be that you needed a radio license to use the band however truckers never got one. The FCC at a point just through up their hands and gave up trying to police that band.
Like VHF (144-148 Mhz) and UHF (300-3000 Mhz) CB is really a "line of sight" band. Like any frequency range, you can use a sky wave antenna (Pointing the antenna driver at the sky) method. If there is a good Ionosphere the wave will be reflected back to the ground hundreds of miles away.
Now on the dedicated amateur radio frequency's, 1m, 2m, 6m , etc yes it is illegal to broadcast messages that are encrypted. 97.113 (4) "Music using a phone emission except as specifically provided elsewhere in this section; communications intended to facilitate a criminal act; messages encoded for the purpose of obscuring their meaning, except as otherwise provided herein; obscene or indecent words or language; or false or deceptive messages, signals or identification."
