[tener]

> Finally, encrypting each bit of a plaintext message comes with major tax on space usage. Each encryption of a single bit corresponds to a list of roughly 700 32-bit integers. If you want to encrypt a 100×100 pixel greyscale image, each pixel of which is an 8-bit integer (0-255), it will cost you 218 MiB to store all the pixels in memory. It’s roughly a 20,000x overhead. For comparison, the music video for Rick Astley’s “Never Gonna Give You Up” at 360p is about 9 MiB (pretty small for a 3 minute video!), but encrypted in FHE would be 188 GiB, which (generously) corresponds to 20 feature-length films at 1080p.

Ouch.