Shadowcast
this was one of the most secret operations ever undertaken by the Alliance. It was a communiations network developed to encrypt messages to deep-cover Alliance agents in Imperial propaganda advertising on the HoloNet. This allowed the leaders of the Alliance to reach those agents and spies who had infiltrated the deepest confidences of the Empire, without raising suspicions. In order to maintain the integrity of the Shadowcast codes, Leia Organa suggested that they be hidden in the Alderaanian moss-painting, Killik Twilight. Although the moss-painting was lost shortly after the destruction of Alderaan, the Alliance - and later, the New Republic - continued to use Shadowcast to communicate with its agents. What the codes used by Shadowcast offered in security, they took away in speed. Each transmission had to be encrypted by hand, then dispatched over a ghost wave. This ghostwave attached itself to a commercial transmission, allowing it to be broadcast on the HoloNet.