Combining ideas in general relativity and information theory, this working paper explores how we can interpret the physics of gravitational lensing as a cosmic cipher - how the bending of light scrambles our observation of its sources, and by knowing where and when light passes near intervening massive bodies, we are able to decode its origins.
In Astro Lounge, I used this cipher to generate photographic prints.
The plane on the left might contain an image, and photons emitted orthogonally (perhaps at the very wavelength of light necessary to represent the pixel value from which the photon originates) will travel towards the right plane. Along the way, any intervening masses will warp the photon's apparent trajectory.
The mass distribution is therefore to the "key" to this cipher. Knowing it allows you to reverse the path of each photon in the cipher image, thereby recovering the original.