This is exactly how most DRM schemes work. You ping the keyserver a key, they check if you're still authorized, and if you are, they send you a key. There's eve

This is exactly how most DRM schemes work. You ping the keyserver a key, they check if you're still authorized, and if you are, they send you a key. There's even a bunch of tech that got built into commercial OSes [1][2] and hardware in an effort to try really, really hard not to expose decrypted content outside some protected path. But if a chunk of decrypted content is displayed on a screen, there's always the analog hole, e.g. taking pictures or a video of the display. Nonetheless, it'd be interesting if all this effort, which got done because of the lobbying of major media rightsholders, was re-used for interpersonal communication. [1] https://en.wikipedia.org/wiki/Protected_Media_Path https://en.wikipedia.org/wiki/Protected_Media_Path [2] https://arstechnica.com/gadgets/2016/11/netflix-4k-streaming-pc-kaby-lake-cpu-windows-10-edge-browser/ https://arstechnica.com/gadgets/2016/11/netflix-4k-streaming...