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Fully homomorphic encryption and the dawn of a private internet

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Re: Fully homomorphic encryption and the dawn of a private internet

#3
I say this as a lover of FHE and the wonderful cryptography around it:

While it’s true that FHE schemes continue to get faster, they don’t really have hope of being comparable to plaintext speeds as long as they rely on bootstrapping. For deep, fundamental reasons, bootstrapping isn’t likely to ever be less than ~1000x overhead.

When folks realized they couldn’t speed up bootstrapping much more, they started talking about hardware acceleration, but it’s a tough sell at time when every last drop of compute is going into LLMs. What $/token cost increase would folks pay for computation under FHE? Unless it’s >1000x, it’s really pretty grim.

For anything like private LLM inference, confidential computing approaches are really the only feasible option. I don’t like trusting hardware, but it’s the best we’ve got!

Re: Fully homomorphic encryption and the dawn of a private internet

#4
post #3

I say this as a lover of FHE and the wonderful cryptography around it: While it’s true that FHE schemes continue to get faster, they don’t really have hope of being comparable to plaintext speeds as long as they rely on bootstrapping. For deep, fundamental reasons, bootstrapping isn’t likely to ever be less than ~1000x overhead. When folks realized they couldn’t speed up bootstrapping much more, they started talking…

Don't you think there is a market for people who want services that have provable privacy even if it costs 1,000 times more? It's not as big a segment as Dropbox but I imagine it's there.

Re: Fully homomorphic encryption and the dawn of a private internet

#5
post #4
post #3

I say this as a lover of FHE and the wonderful cryptography around it: While it’s true that FHE schemes continue to get faster, they don’t really have hope of being comparable to plaintext speeds as long as they rely on bootstrapping. For deep, fundamental reasons, bootstrapping isn’t likely to ever be less than ~1000x overhead. When folks realized they couldn’t speed up bootstrapping much more, they started talking…

Don't you think there is a market for people who want services that have provable privacy even if it costs 1,000 times more? It's not as big a segment as Dropbox but I imagine it's there.

???

For the equivalent of $500 in credit you could self host the entire thing!

Re: Fully homomorphic encryption and the dawn of a private internet

#6
post #4
post #3

I say this as a lover of FHE and the wonderful cryptography around it: While it’s true that FHE schemes continue to get faster, they don’t really have hope of being comparable to plaintext speeds as long as they rely on bootstrapping. For deep, fundamental reasons, bootstrapping isn’t likely to ever be less than ~1000x overhead. When folks realized they couldn’t speed up bootstrapping much more, they started talking…

Don't you think there is a market for people who want services that have provable privacy even if it costs 1,000 times more? It's not as big a segment as Dropbox but I imagine it's there.

there is, it's called governments. however this technology is so slow that using it in mission critical systems (think communication / coordinates during warfare) that it is not feasible IMO.

the parent post is right, confidential compute is really what we've got.

Re: Fully homomorphic encryption and the dawn of a private internet

#7
I 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.

Re: Fully homomorphic encryption and the dawn of a private internet

#8
post #7

I 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 the…

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.

Re: Fully homomorphic encryption and the dawn of a private internet

#10
Ok, lets stop being delusional here. I'll tell you how this will actualy work:

Imagine your device sending Google an encrypted query and getting back the exact results it wanted — without you having any way of knowing what that query was or what result they returned. The technique to do that is called Fully Homomorphic Encryption (FHE).

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