A message cube was a device which was essentially unsliceable, since the cube could be keyed to an individuals body chemistry, fingerprints, or even their voice. The cube could be hollow, used for delivering anything small in nature, such as physical media and datachips. It could even be built around a tiny holoprojector.

During the First Corellian Insurrection, Mara Jade was delivered a message cube addressed to Chief of State Leia Organa Solo. The cube revealed the plans of the Sacorrian Triad and the Human League, headed by Han's cousin Thrackan Sal-Solo, to attack the New Republic.