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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

#121

Post by charles_f »

teo_zero wrote: post #18

I think the opening example involving Google is misleading. When I hear "Google" I think "search the web". The articles is about getting an input encrypted with key k, processing it without decrypting it, and sending back an output that is encrypted with key k, too. Now it looks to me that the whole input must be encrypted with key k. But in the search example, the inputs include a query (which could be encrypted wit…

I don't know, when I hear Google I hear Gmail, Google docs, and every other service they have to know about people. My mom would probably think mostly about search, but then she would not read an article about HME

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

#122

Post by maerF0x0 »

FHE is an important tool because right now companies can be coerced by governments to break encryption for specific targets. FHE removes the need for companies to have a back bone, they can simply shrug and say "We literally do not see the plaintext, ever". They can kinda do this with End to End encryption when they're simply the network/carrier, but cannot currently do this anytime they're processing the plaintext data.

I come from a values basis that privacy is a human right, and governments should be extremely limited in retailiatory powers against a just and democratic usage of powers against them. (things like voting, arts, media, free speech etc)

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

#123

Post by charcircuit »

johnisgood wrote: post #102
charcircuit wrote: post #61

How do you send a password reset email with this. Eventually your mail server will need the plaintext address in order to send the email. And that point can be leaked in a data breach. It's idealistic to think this could solve data braches because businesses knowing who their customers are is such a fundamental concept.

A password reset e-mail is supposed to expire pretty quickly though, so would it really matter in practice?

The email must be able to be used at any time which means that and attacker may be able to also "use" them.

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

#124

Post by JohnFen »

ramchip wrote: post #117
JohnFen wrote: post #114

Here's what I don't understand about homomorphic encryption and so struggle to trust in the very concept. If you can process encrypted data and get useful results, then a major part of the purpose of encryption is defeated, right? How am I wrong?

The result is encrypted. It's useful to the key holder, not to the party doing the computation.

Yes, I understand that part. The part I struggle with is how the very fact that a party without the key can do the computation on it is not an indication that the encryption is leaking information. If the encryption were airtight, then such computation shouldn't be possible.

Given that cryptography experts seem to be asserting otherwise, I assume that there's something important that I'm not understanding here.

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

#125

Post by dcow »

Tryk wrote: post #87
littlecranky67 wrote: post #27

Earlier quoted context omitted.

While correct, that doesn't answer the question at all, though. If I have my address book submited into an FHE system and want to sort by name - how do you do that if the FHE system does not have access to cleartext names?

When comparing two ciphertexts A,B a FHE sorting function will output a sorted pair of two new ciphertexts: E.g. FHE_SORT(A,B) -> (X,Y) where Dec(X) But without decoding, there's no way of knowing whether X (or Y) comes from A or B. Source: II. D of https://eprint.iacr.org/2015/995.pdf

It’s not that simple. The client has to send the server the comparison function.

To do anything practical the server usually needs to provide the client with gigabytes of per-client-key encrypted seed data.

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

#127

Post by Forgeties79 »

ralferoo wrote: post #115
crtasm wrote: post #111

Earlier quoted context omitted.

Do they offer deals like that often? List price is "from $24/month" for 6TB (no further details provided without registering an account).

They tend to do promotions, typically only valid for 24h and only advertised on certain forums like LET, a couple of times per year - typically at least around their company anniversary date or Black Friday. There are others too, e.g. Servarica who keep their Black Friday offers running all year round.

> There are others too, e.g. Servarica who keep their Black Friday offers running all year round.

I don’t understand the logic here so I’m going to assume I’m being obtuse. Doesn’t that just mean that’s their standard price? Why or how would you ever pay more?

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

#128

Post by JohnFen »

dachrillz wrote: post #19
paulrudy wrote: post #9

> FHE enables computation on encrypted data This is fascinating. Could someone ELI5 how computation can work using encrypted data? And does "computation" apply to ordinary internet transactions like when using a REST API, for example?

A very basic way of how it works: encryption is basically just a function e(m, k)=c. “m” is your plaintext and “c” is the encrypted data. We call it an encryption function if the output looks random to anyone that does not have the key If we could find some kind of function “e” that preserves the underlying structure even when the data is encrypted you have the outline of a homomorphic system. E.g. if the following h…

> If we could find some kind of function “e” that preserves the underlying structure even when the data is encrypted

But isn't such a function a weakened form of encryption? Properly encrypted data should be indistinguishable from noise. "Preserving underlying structure" seems to me to be in opposition to the goal of encryption.

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

#129

Post by adamc »

niclas-183 wrote: post #82
perlgeek wrote: post #63

FHE might allow arbitrary computation, but I use most services because they have some data I want to use: their search index, their knowledge, their database of chemicals, my bank account transactions, whatever. So unless Google lets me encrypt their entire search index, they can still see my query at the time it interacts with the index, or else they cannot fulfill it. The other point is incentives: outside of some…

Exactly what I thought. In the end it really isn't in most of the big corps interest to not see your data/query. They need/want to see it so why would they degrade their ability to do so if they can just say no and you will have to rely on using their services without FHE. For banking applications cool, everyone else debatable if it will ever be accepted.

Would depend on market pressures, no?

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

#130

Post by teddyh »

thrance wrote: post #93
perlgeek wrote: post #63

FHE might allow arbitrary computation, but I use most services because they have some data I want to use: their search index, their knowledge, their database of chemicals, my bank account transactions, whatever. So unless Google lets me encrypt their entire search index, they can still see my query at the time it interacts with the index, or else they cannot fulfill it. The other point is incentives: outside of some…

Here's an implementation of a fully private search engine using FHE that allows querying Wikipedia with the server remaining oblivious as to what you're reading: https://spiralwiki.com/

It’s ridiculously easier just to download a Wikipedia database dump and read it locally, with Kiwix: https://kiwix.org/>
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