alt Hacker NewsI get the "client side" of this equation; some number of users want to keep their actions/data private enough that they are willing to pay for it.
What I don't think they necessarily appreciate is how expensive that would be, and consequently how few people would sign up.
I'm not even assuming that the compute cost would be higher than currently. Let's leave aside the expected multiples in compute cost - although they won't help.
Assume, for example, a privacy-first Google replacement. What does that cost? (Google revenue is a good place to start that Calc.) Even if it was say $100 a year (hint; it's not) how many users would sign up for that? Some sure, but a long long way away from a noticeable percentage.
Once we start adding zeros to that number (to cover the additional compute cost) it gets even lower.
While imperfect, things like Tor provide most of the benefit, and cost nothing. As an alternative it's an option.
I'm not saying that HE is useless. I'm saying it'll need to be paid for, and the numbers that will pay to play will be tiny.
An FHE Google today would be incredible expensive and incredibly slow. No one would pay for it.
The key question I think is how much computing speed will improve in the future. If we assume FHE will take 1000x more time, but hardware also becomes 1000x faster, then the FHE performance will be similar to today's plaintext speed.
Predicting the future is impossible, but as software improves and hardware becoming faster and cheaper every year, and as FHE provides a unique value of privacy, it's plausible that at some point it can become the default (if not 10 years, maybe in 50 years).
Today's hardware is many orders of magnitudes faster compared to 50 years ago.
There are of course other issues too. Like ciphertext size being much larger than plaintext, and requirement of encrypting whole models or indexes per client on the server side.
FHE is not practical for most things yet, but its venn diagram of feasible applications will only grow. And I believe there will be a time in the future that its venn diagram covers search engines and LLMs.