"If we're going to be consistent and advocate freedom of speech we have to advocate freedom of encrypted speech too. The genie is out of the bottle, cryptologically."
- Neal Stephenson

The hyphenated phrase "contra-gravity" is used early on in science fiction. The Golden Age story Barton's Island, written in 1929 by Harl Vincent describes it:

It had been his discoveries that revolutionized aviation in 2219 and brought him into prominence in the engineering fraternity at the early âge of thirty. For nearly three centuries previously the relation of the gravitational to the electro-magnetic field was known, it having been proved mathematically in the twentieth century. But it remained for Philip Barton to discover means of utilizing this knowledge for the benefit of mankind. His method of producing contra-gravitational fields had eliminated the use of wings and vertical lifting propellers on ail types of air craft. And later his reaction motor obviated the necessity of the horizontal propellers as well, and provided not only much greater fuel economy, but entire independence of the density of air as a medium for obtaining propulsive effect.

The engine room of the Inquisitor was provided with two contra-field generators, each of sufficient power to support the vessel when fully loaded. These generators were of the most improved type, and were connected to fore and aft pole pieces from whence the contra-gravity flux emanated. When these were energized, a field was produced that could be varied in intensity at will, as well as reversed if the necessity arose. The basic discovery of the graviton had led Barton to the development of this unique apparatus, and the zenith of perfection had been reached in this particular portion of the Inquisitor's mechanism. The graviton, be it remembered, was identified by Barton in the laboratory as a close analogy to the magneton, that final element of magnetism whose relation to magnetism is similar to that of the electron to electricity. Its relation to the earth's gravity field being determined, it was a logical, though by no means a simple, step to the artificial generation of gravitons, both positive and negative. The method of producing a negative gravitonic field surrounding two poles composed of the metal bartonite was his final development, and the world found itself in the possession of a practical means of getting away from the surface of the earth by the repulsive force of the opposing fields.