alt Hacker Newshttps://www.jeremykun.com/2024/05/04/fhe-overview/#the-highe...
> Fourth, there is a bandwidth concern. FHE encryption schemes generally increase the size of the data being encrypted, and the user must send the server a special set of encryption keys to enable the computation, which are relatively large as well. The special keys need only be generated and sent once and can be used for all future computations, but they can easily be gigabytes in size. In one example FHE scheme with lightweight keys, a ciphertext encrypting a single integer is on the order of 25 KB, and the special keys are about 0.5 GB. In others, 16,000 or more integers are packed into a single ciphertext of similar size, but the keys can be 10s of GiBs.
I'm still a bit skeptic - 1000x sounds overly optimistic and only looking at encryption transformation without any operation is already at least 10000x with scheme mentioned in that quote.
Sibling comment estimates lower bounds of current research at minimun 10^6 overhead which sounds more realistic.