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weatherlite 12 seconds ago [-]
> Google is making private AI practical with homomorphic encryption
I don't understand why we need to bring LGBTQ+ into everything
meindnoch 20 minutes ago [-]
Great, private AI, at the cost of >1000x the resource usage. Because apparently AI companies weren't already using quite enough energy to cook the planet.
The most private AI is the one running on my own hardware, not in some giant data center.
sabretooth1405 3 hours ago [-]
My master's thesis is on a topic in this field (Privacy Preserving ML) and from my understanding HE and other techniques have very high overheads(~10^3) on inference tasks and thus aren't very commercially viable.
dhx 2 hours ago [-]
To throw out some real and up-to-date numbers from [1] for FHE at "128-bit security level", to sort 8x 8-bit unsigned integers on the most ordinary of desktop PCs, wait 3 seconds for the result. Want to sort 32x 8-bit unsigned integers instead? Come back 34 seconds later for the result.
update: also see [2] for some primitive unsigned 64-bit integer operation benchmarks with the TFHE-rs library (winner in the sorting performance comparison of [1]). Equality at 80ms, addition and subtraction at 100ms, division at 8 seconds, etc.
[1] https://eprint.iacr.org/2026/1495.pdf Oblivious Sorting under Fully Homomorphic Encryption: A Comprehensive Survey and Performance Analysis, Omar Ahmed and Rostin Shokri and Nektarios Georgios Tsoutsos, 2026
The article conspicuously fails to go into much detail about that. I poked around with an AI a bit (to rapidly cover all the linked pages) and it seems the best numbers we can get are from this arxiv paper: https://arxiv.org/html/2506.18150v4 Which says:
"We evaluate HE-LRM on UCI (health prediction) and Criteo (click prediction), achieving inference latencies of 24 seconds on UCI and 228 to 489 seconds, respectively, on a single-threaded CPU."
There don't seem to be any direct comparisons available, probably because nobody else has any reason to limit themselves to one single-threaded CPU with normal techniques, but for reference the AI seems to expect that normal times for conventional setups are in the milliseconds range, fairly comfortably, even on CPU. I didn't find a clean primary source to link to for this claim, but clicking through various things that don't cleanly state the situation it did seem plausible. So we seem to still be in the range of single-digit orders of magnitude slower, possibly as much as 5 or 6, which is to say, we're still talking the range where we need to take the log of the difference to get sensible numbers, we're not using percentages.
(To run it yourself, I basically just fed the URL from the HN link, mentioned that FHE is known to be slow, and asked if anything linked in the blog post gave concrete times.)
j2kun 53 minutes ago [-]
The linked repository has demos you can run (though you have to install bazel), and some of the smaller models run inference in about a second, while the larger ones take minutes.
That said, there is a lot of ongoing work on GPU acceleration. Cf. the recent FHE-based CIFAR demo that runs in 200ms: https://sofar.belfortlabs.cloud/
Still maybe 1000x slower than cleartext, but progress!
bevekspldnw 2 hours ago [-]
Commercially viable for Google boils down to can they attribute ads behaviors to it or not.
Then there’s a second tier of things that just make those wheels turn and if they do or don’t make ads revenue is nominally immaterial.
The teams doing this stuff at Google are purely for show, none of this makes it into any real products.
There’s the narrow exception of stuff like gboard, that does use privacy preserving ML/fed learning, but this stuff isn’t in the same zone.
I find it a bit embarrassing when Google publishes this stuff to be honest.
luckydata 2 hours ago [-]
You are very wrong about all of this btw.
bevekspldnw 1 hours ago [-]
You literally don’t know who I am or the roles I had. So unless you can tell me how many steps you were from Kent Walker and what you worked on I’m gonna bet a hell of a lot I know more than you.
Edit to clarify my prior point: some of the technology makes it into the product, but the putative data protections do not.
Why?
Because there is always a work around, and ads legal will approve it every time.
2 hours ago [-]
abetusk 2 hours ago [-]
1000x slowdown is bad but not a complete deal breaker. Do you have a sense of what a reasonable achievable factor is? Do you have sense for how long before we get to that achievable factor?
u1hcw9nx 2 hours ago [-]
That's the reason for HEIR like optimization and parameter selection.
It narrows the 10^3 - 10^6 penalty to 10x - 100x.
dietr1ch 2 hours ago [-]
Exactly my concern, and worse overhead that what I recalled.
Cost-wise the only viable private compute is local compute. It's more expensive than cloud, but true private compute in the cloud is definitely pricier.
clayhacks 2 hours ago [-]
Do you think that’s like a fundamental limit or something that will improve with time and new algorithms?
drblast 23 minutes ago [-]
I did some amount of research into the feasibility of PHE and FHE about 20 years ago, and my conclusion at the time was that the space overhead of the encrypted output was a massive bottleneck, which meant that while it was potentially useful in a small number of niche cases it wasn't ever going to be practical for general-purpose computations without a major breakthrough.
The gist was I could do an encrypted (int)x + (int)y = (int)z computation, I could encrypt the inputs and then get a result back that was correct, secure, and decryptable, but was like 1MB in size.
So, for someone whose knowledge is 20 years outdated and is about Pallier crypto, has that major breakthrough happened?
lsb 2 hours ago [-]
Google is making private AI practical with Gemma4 something that you can run without an Internet connection.
All of the proofs of privacy rely on us getting the math right. All of the privacy from unplugging your internet cable is there by default.
Cider9986 3 hours ago [-]
This is the same Google that doesn't have e2ee on their password manager by default. Like WTF, it's a password manager.
aeturnum 12 minutes ago [-]
I think that, if you are under the impression that having an administrative back door is an unpopular feature, then you should speak to more of your non-technical friends about their experience of technology. I think you'll find that the people who could most benefit from a password manager often don't have good credential management and would be worse off if they lost all their passwords when they forgot or lost their master password.
bitpush 2 hours ago [-]
F. Scott Fitzgerald's test of top-tier intelligence -
> Holding two opposing views in the mind means accepting two contradictory ideas at the same time without needing to pick one side or rush to a simple answer
I continue to use Apple products because they are top class even though everytime I think of Tim Cook in the Oval Office presenting the gold plaque to the current president, it makes me wanna puke. World isnt black or white.
Cider9986 49 minutes ago [-]
The reason I mentioned it is because Google seems to have a strange aversion to E2EE. Apple has added the option to iCloud but Google only has one consumer facing E2EE producted, Google messages. A password manager is the most obviously important place to use it. I can't name another password manager that isn't.
rpedroso 36 minutes ago [-]
How many customers are using Google Password Manager? How much revenue does it generate? What would it cost to add E2EE? How would it affect the UX? How much revenue would it generate? What projects would have to be de-prioritized to fund this work?
I agree, a password manager without E2EE is unusable in my eyes. However, I can also understand the institutional reasons this might be the case. I don't think it reflects an organizational aversion to E2EE.
ameliaquining 24 minutes ago [-]
[dead]
amazingamazing 2 hours ago [-]
If you think about it for a moment you will realize the average user does not want that.
kingleopold 1 hours ago [-]
yes, lastpass get $ tens millions because its weak and gets hacked not because its realiable, secure and great.
rexpop 2 hours ago [-]
I suspect that your one moment of thought follows many years of contemplation. Maybe you can fill us in on some of that background.
giovannibonetti 2 hours ago [-]
E2E encryption means that if the user loses the keys, there is no way to recover that even if they contact support and prove the data belongs to them.
amazingamazing 2 hours ago [-]
How do you make e2e password management work on multiple devices as convenient as not? You cannot.
Most people who use Google trust them. And if you do not trust them then why are you using their password manager? You see? Hence why they do not bother.
Of course one might read this and say, multi device e2ee is possible! Sure, but can you allow for recovery when people inevitably lose their recovery codes at scale? If you really care about this it is not necessary to go with Google.
I stand by my original comment:
The average user does not want it.
bmenrigh 2 hours ago [-]
Has FHE really progressed so far that it's now so efficient that doing computation on an encrypted prompt is feasible? I thought even basic operations like FHE addition were still thousands of times more complex. The only mention in the article I see is:
> But while homomorphic encryption has a nontrivial cost overhead, it shifts the capability/privacy trade-off to a question of cost. And the cost of homomorphic encryption is rapidly decreasing.
Which doesn't spell out exactly hon "nontrivial" the cost overhead still is.
mswphd 30 minutes ago [-]
addition is easy/essentially the same cost as standard (not really, because you have to compute mod p addition rather than mod 2^32, but ignoroing that it's roughly the same).
as a general rule multiplication is the difficult part.
it's hard to accurately quantify what "nontrivial" cost overheads are because they're very application dependent. for example, things that require encrypted control flow are very hard under FHE. so an encrypted hashmap sounds roughly unimplemnetable. but things that do not require encrypted control flow (e.g. many ML applications) are less bad. this can still be quite bad though. for example, relu is trivial in plaintext. it is hard homomorphically, because the trivial way to write it uses private control flow.
sean_pedersen 18 minutes ago [-]
There are LLM models which compute only using addition no?
p0w3n3d 41 minutes ago [-]
Ideally: we will have private AI
Reality: our computers will be used as distributed AI calculators
sheesdev 2 hours ago [-]
I've published two papers on using HE for ML and it's nice, but also alarming, to see big players like Google and Microsoft making decent tools for performing HE. Although the technology is still much farther out from being commercially viable, it does pose an interesting problem about how these data aggregation companies will utilise a tech that is inherently private.
j2kun 56 minutes ago [-]
One potentially simple answer is: to make things that are otherwise illegal (for regulatory reasons) possible.
There are some instances of hand-built cryptographic protocols used in production at Google that use FHE in small doses (e.g., computing a single dot product as part of an interactive protocol), so the big question is whether having a general-purpose tool will expand the feasibility of applying these to other, maybe less critical projects that still want some privacy guarantees but can't afford to hire cryptographers.
tolugenius 2 hours ago [-]
I guess I'm curious from your perspective what and why makes the tech from being commercially viable, and the concerns of big players adopting this (which was always going to happen I imagine, but when shapes a lot of the future of the field).
NyxWulf 2 hours ago [-]
Maybe I'm not understanding this, but how is it that you can know enough about the data to process it without undermining the fundamental concept of encryption? Isn't encrypted data supposed to be just random noise without the key? The more you know about the underlying data the easier it gets to decrypt? Does this mean someone can just steal your encrypted data and use that to steal your identity without even needing to decrypt it anymore?
luckydata 2 hours ago [-]
you can produce a correct result without knowing what that result means as long as the person you then provide that result to can decrypt it. So the way it works is the server does the job on data it can't read, sends an answer to the device, the device decrypts it.
It's very useful for things like healthcare data for example but also for products like "home assistants", and it's one of the use cases that the team hiring internally was giving in their job req. I tried to apply too but didn't get it unfortunately, this was a very interesting product to work on imho, congrats to whoever got my job :)
Deukhoofd 3 hours ago [-]
It sounds neat, but I do wonder how viable this is commercially. How high do we rate the chances that governments around the world will step in before another kind of E2E is rolled out.
3 hours ago [-]
nazgulsenpai 2 hours ago [-]
Why is the bold letter n lighter than the rest in this page's font?
nullc 28 minutes ago [-]
Private AI is practical by running the model locally, every much more so than any homomorphic encryption scheme.
So essentially the headline sells this as work to keep your data private, but really it's work to keep the AI-- which was trained on your code and your writing-- private.
FloatArtifact 4 hours ago [-]
Encryption or not, if it's on somebody else's server, it isn't yours. I don't believe Google has my best interest.
u1hcw9nx 4 hours ago [-]
With Fully Homomorphic Encryption it's nobody elses.
The basic idea of of the project is to remove the need for trust.
unsungNovelty 3 hours ago [-]
It's google. They are good at engineering. Not at creating trust. After the bizillionth time they have broken trust, there is no need for benefit of the doubt.
Plont 3 hours ago [-]
Yeah. Google is an ad business. Their entire motive for getting invested in AI is ad revenue. We're supposed to believe they just... won't turn on the money fountain? After going into the red for their data center investments? Hell nah.
I'd expect this to be something like the Google Ad ID: technically separated from what Google considers personal information, but trivially easy to tie back to an individual person and to other information about that person.
They're continually breaking trust by illegally scraping up the internet to feed to their plagiarism machine, which they are now asking us to trust with more data. It's not a compelling arguement.
ameliaquining 19 minutes ago [-]
This blog post is about an open source project that you can look at for yourself and decide whether it's suitable for your use case.
throwaway27448 3 hours ago [-]
There's more to life than branding.
tonyhart7 3 hours ago [-]
so what's the option ??? Meta ?? xAi ?? or OpenAI ???
unsungNovelty 3 hours ago [-]
Why should there by any reason to look at the above ones? We are talking about this B2C company which effects a lot of our lives. The discussion isn't about that or this. The discussion is about JUST this specific company.
2 hours ago [-]
thih9 3 hours ago [-]
To what end?
u1hcw9nx 2 hours ago [-]
Biometric authentication, credential checking, blind auctions, threat matching (search zero-day signatures without revealing the vectors), private dna matching or running queries of medical symptoms and health records against databases.
I think the most immediately useful is checking if a username/password hash appears in a leaked database without revealing which account or password hash is being checked.
kccqzy 3 hours ago [-]
This kind of attitude is really disrespectful of decades of progress in cryptography. Without even considering homomorphic encryption, classic encryption is specifically designed to make intermediate nodes such as ISP dumb pipes that do not know the contents of communication. The ISP can store your communications on their server however they want.
If you don’t agree with this model, I’m afraid modern cryptography doesn’t have anything to offer.
jewel 2 hours ago [-]
Even if your files are properly encrypted, if you keep them on, say, Google Drive, then you might lose access to them if your account gets inadvertently blocked.
I think GP is trying to say something along those lines. Not that encryption isn't trustworthy, but that even with homomorphic encryption you still give up autonomy.
krunck 3 hours ago [-]
It's FHE for "cryptographically-secure private AI inference" not for every other service where they snoop into your behavioral information.
yjftsjthsd-h 2 hours ago [-]
It can give you confidentiality without availability. Not sure about integrity? Anyways, still useful.
mohamedkoubaa 2 hours ago [-]
Anything to keep people from running local models
oulipo 2 hours ago [-]
Zama.ai is also a player in this space
noident 3 hours ago [-]
Does this rely on the Trust Me Bro model, or is there some way for the client to verify that the provider actually isn't able to see your inputs?
I want to read a whitepaper but all I can find is the tl;dw conference presentation
eslaught 3 hours ago [-]
The linked project page [1] claims to be fully homomorphic. Assuming the claim holds (I haven't verified it), then there is provably no way for Google or anyone else to obtain any information from the encrypted data or computation performed on them.
FHE is traditionally horrifically slow, so it's hard to imagine running anything beyond toy models with it. They list some applications on the original article page, but (presumably) they must be dramatically stripped down in order to run within any reasonable time budget. This is not going to run anything like a Sol/Opus any time soon.
Related, I'd seen this blog [0] posted on HN a few years back that gave a nice run down on the "programmable cryptography" space which introduce FHE and a few other neat concepts. Really enjoyed the read and learned some new terms.
One flaw with FHE is that it guarantees only that you need the key to see the inputs or outputs of the computation, but not necessarily that the computation is the one you want. For example, the computation could be adversarial for certain inputs, or an adversary could insert their own computation first (or last).
mswphd 27 minutes ago [-]
note that this is even true for an honest server. Roughly, FHE computations often require certain bounds on the (encrypted) messages for things like tuning polynomial approximation domains etc. If your messages are out of distribution for the tuned polynomial approximations you'll get back garbage as as result.
noman-land 3 hours ago [-]
100% not an expert but my understanding was that part of what you are proving by signing the computation is that the computation itself was performed specifically as agreed to. I may be mixing this up with zero knowledge proofs.
LoganDark 3 hours ago [-]
If this were the case it would be necessary to send the entire model weights in response to every request which would be a bit inconvenient.
drdeca 2 hours ago [-]
Hmm, could one instead of sending the model weights, send like, a merkle tree root for them, not exactly specifying the model, but at least demonstrating that the same model is used each time?
jrm4 3 hours ago [-]
Correct. I appreciate the theoretical technology here, but I believe a great deal of harm is done by the fact that people are not likely to understand exactly what this means.
Which is to say, I believe that google is strongly implying the falsehood of "no one at Google can read your stuff."
filup 3 hours ago [-]
Proper encryption means the ciphertext is indistinguishable from noise. So...in order to be able to process on it, you have to make it not indistinguishable from noise.
So I take offense to the term FHE. It's a oxymoron.
The whole thing immidiatly stands out as a sham to build trust where it's gone.
Veserv 12 minutes ago [-]
You are objectively wrong. The math is straightforward to show that you can operate on a ciphertext securely in some cryptosystems.
Consider two integers M1 and M2.
Consider RSA with private key (E), public key (D), and public modulus (N).
Encrypt(M, E, N) = mod(pow(M, E), N).
Decrypt(C, D, N) = mod(pow(C, D), N).
mod(Encrypt(M1, E, N) * Encrypt(M2, E, N), N) = mod(Encrypt(M1 * M2, E, N), N).
So, for all RSA encryption, multiplying the ciphertexts results in a ciphertext that is the multiple of the plaintexts. However, unless you can break RSA, you can not determine what numbers you multiplied or what the final multiplied number is.
This is not a fully homomorphic system as it only allows multiplication, but it is a existence proof that you can do operations on ciphertext that apply to the plaintext without being able to recover the plaintext unless you can break the encryption directly.
flambo 2 hours ago [-]
This is actually the magic of FHE. The ciphertext is indistinguishable from noise AND can be computed on, it just looks like different noise.
If you believe the underlying cryptographic hardness assumption of LWE/RLWE/etc, then yes Google cannot see any of the input or output of the model.
filup 2 hours ago [-]
If it only appears indistinguishable from noise, but it's actually not, then it's just deception.
drdeca 2 hours ago [-]
They didn’t say that it “appears” indistinguishable from noise, but that it is indistinguishable.
It seems like you strongly believe otherwise, but I suspect you don’t have a good reason to, and just find it unbelievable.
Do you think you can distinguish it from noise, if given an implementation and the information an adversary would have access to?
Of course, you not being able to wouldn’t demonstrate that noöne can. But, it seems like if you had a good reason to believe that an adversary can, that would suggest you might have some idea of how they could do so. And, if you do have such an idea, then, if that idea works, it would be important for others to know, and if it doesn’t, it would presumably benefit your understanding to see why it doesn’t.
filup 1 hours ago [-]
>They didn’t say that it “appears” indistinguishable from noise, but that it is indistinguishable.
That's the oxymoron. If it was indistinguishable nothing could be gained.
It's not about me being able to distinguish it. It's the model provider saying they cant, when they can.
pluto_modadic 3 hours ago [-]
they could have gone with an oblivious transfer approach (where it's working on what looks like multiple problems at once, you don't know which)
drdeca 3 hours ago [-]
Eh? With secret sharing one can do computation on a shared secret where it is provable that no individual party can recover any information about the data with their share alone.
I don’t see why you conclude that FHE couldn’t be close to as secure as that. (Like, not information theoretically, but with computationally bounded adversaries.)
filup 2 hours ago [-]
I'm not saying that you can't design a system for secure cloud computing.
drdeca 2 hours ago [-]
You said that FHE is an oxymoron, seemingly on the basis that in proper encryption the ciphertext is indistinguishable from noise, and you think this can’t be true of FHE. I am arguing to the contrary.
In the secret sharing multi-party computation schemes, the individual shares of the secret are random and have no information about the plaintext.
I see no reason that FHE can’t have ciphertexts indistinguishable from noise.
Ar-Curunir 2 hours ago [-]
No, that’s not what proper encryption means. Security for encryption means that cipher texts encrypting distinct messages are indistinguishable. This is called IND-CPA, and FHE satisfies this.
filup 2 hours ago [-]
How can it possibly pass indcpa. If the model can give me any valuable information about the cipher. Apparently the middle man would know precisely what is contained in the payload.
drdeca 2 hours ago [-]
Here’s a very simple one-time-pad style construction for homeomorphic (but not fully homeomorphic) encryption.
Suppose the plaintext, ciphertext, and key, are each a natural number modulo 5.
The key is selected uniformly at random. The ciphertext is obtained by adding the key to the plaintext (and as a result is also uniform random).
Then the ciphertext is sent to the server. The server only has the ciphertext, which is uniform random. The server then adds some integer mod 5 to the ciphertext, producing a new ciphertext, and sends it back to the user. The user then subtracts their key from the new ciphertext to obtain the new plaintext, which is their original plaintext plus the number the server added.
At no point in this process did the server learn anything about the user’s plaintext.
This is clearly secure.
It is also useless, because just adding a number isn’t a useful thing for a server to do (they may as well just send the user the number and let them add it themselves), but that’s because it is a toy example.
I suppose if mind uploading were possible, then under FHE it would in principle be possible to take the ciphertext and run the computation of “this mind upload of this person reads the data and provides some output”, and then presumably that uploaded person would have the experience of seeing the plaintext? But it wouldn’t be possible to get any information about the plaintext without the key (or enough brute force to find the key, but that’s why we use big enough keys to make this infeasible).
filup 1 hours ago [-]
What does that have to do with incpa?
I send this server a question encrypted. It stays encrypted yet the server distinguished my ciphertext enough to produce a coherent reply. That means there was enough information in the ciphertext for the server to perform the inference, even if it was obscured to where it looks indistinguishable, it apparently wasn't.
This doesn't remove trust from the equation, it puts the trust directly on the algorithm. Probably one no one can explain to me like I'm 5. But because it's encrypted I am no longer breaking the law by processing on protected data. I imagine very large contracts await on the other side. Lots of money to be made.
mswphd 22 minutes ago [-]
the server doesn't do what you say. Roughly, the server has a fixed circuit C they run on the ciphertext. They run this same circuit on any ciphertext. They give you back the result. the fact that the result, when decrypted, gives the desired answer isn't something the server can verify though.
Think about a very simple setting, say a database lookup. I send an index `i` in a database I want to lookup. The server sends back DB[i] or whatever.
In the clear, the server can immediately fetch the correct row. Under FHE, the server does a full scan of the database, and (roughly) for each row will do something like DB[i] * (encrypted selector variable that is 0 or 1 depending on if it is the row you want).
This is actually a baby version of FHE known as "Private Information Retrieval". For it, you (roughly) can design an encryption scheme that supports linear function evaluation. For example, a ciphertext Enc(m) can be paired with a matrix A to produce Enc(Am). You can then encrypt the ith basis vector m := e_i, and view the database as a matrix DB, to get DB * Enc(e_i) = Enc(DB*e_i) = Enc(DB_i). This works, and can be implemented in ~1k LoC, e.g. it is not particularly complicated to practically instantiate (though this basic sketch has some performance issues).
traceroute66 2 hours ago [-]
Quoted from the blog post:
> user-data can be protected from data breaches, but then the service provider cannot provide features that depend on the data, such as spam or virus detection
I think they forgot "or advertising" at the end.
I don't trust Google. I would much prefer to use on-prem or - at most - one of the secure-enclave providers like Tinfoil[1] or Private Mode[2]
Secure Enclaves are broken all the time though [1]. They’re also not secure against attacks from a quantum computer (including store now decrypt later attacks). At least with symmetric FHE, anything that happens after encryption requires zero trust.
I don't understand why we need to bring LGBTQ+ into everything
The most private AI is the one running on my own hardware, not in some giant data center.
update: also see [2] for some primitive unsigned 64-bit integer operation benchmarks with the TFHE-rs library (winner in the sorting performance comparison of [1]). Equality at 80ms, addition and subtraction at 100ms, division at 8 seconds, etc.
[1] https://eprint.iacr.org/2026/1495.pdf Oblivious Sorting under Fully Homomorphic Encryption: A Comprehensive Survey and Performance Analysis, Omar Ahmed and Rostin Shokri and Nektarios Georgios Tsoutsos, 2026
[2] https://docs.zama.org/tfhe-rs/tfhe-rs/1.0/get-started/benchm...
"We evaluate HE-LRM on UCI (health prediction) and Criteo (click prediction), achieving inference latencies of 24 seconds on UCI and 228 to 489 seconds, respectively, on a single-threaded CPU."
There don't seem to be any direct comparisons available, probably because nobody else has any reason to limit themselves to one single-threaded CPU with normal techniques, but for reference the AI seems to expect that normal times for conventional setups are in the milliseconds range, fairly comfortably, even on CPU. I didn't find a clean primary source to link to for this claim, but clicking through various things that don't cleanly state the situation it did seem plausible. So we seem to still be in the range of single-digit orders of magnitude slower, possibly as much as 5 or 6, which is to say, we're still talking the range where we need to take the log of the difference to get sensible numbers, we're not using percentages.
(To run it yourself, I basically just fed the URL from the HN link, mentioned that FHE is known to be slow, and asked if anything linked in the blog post gave concrete times.)
That said, there is a lot of ongoing work on GPU acceleration. Cf. the recent FHE-based CIFAR demo that runs in 200ms: https://sofar.belfortlabs.cloud/
Still maybe 1000x slower than cleartext, but progress!
Then there’s a second tier of things that just make those wheels turn and if they do or don’t make ads revenue is nominally immaterial.
The teams doing this stuff at Google are purely for show, none of this makes it into any real products.
There’s the narrow exception of stuff like gboard, that does use privacy preserving ML/fed learning, but this stuff isn’t in the same zone.
I find it a bit embarrassing when Google publishes this stuff to be honest.
Edit to clarify my prior point: some of the technology makes it into the product, but the putative data protections do not.
Why?
Because there is always a work around, and ads legal will approve it every time.
It narrows the 10^3 - 10^6 penalty to 10x - 100x.
Cost-wise the only viable private compute is local compute. It's more expensive than cloud, but true private compute in the cloud is definitely pricier.
The gist was I could do an encrypted (int)x + (int)y = (int)z computation, I could encrypt the inputs and then get a result back that was correct, secure, and decryptable, but was like 1MB in size.
So, for someone whose knowledge is 20 years outdated and is about Pallier crypto, has that major breakthrough happened?
All of the proofs of privacy rely on us getting the math right. All of the privacy from unplugging your internet cable is there by default.
> Holding two opposing views in the mind means accepting two contradictory ideas at the same time without needing to pick one side or rush to a simple answer
I continue to use Apple products because they are top class even though everytime I think of Tim Cook in the Oval Office presenting the gold plaque to the current president, it makes me wanna puke. World isnt black or white.
I agree, a password manager without E2EE is unusable in my eyes. However, I can also understand the institutional reasons this might be the case. I don't think it reflects an organizational aversion to E2EE.
Most people who use Google trust them. And if you do not trust them then why are you using their password manager? You see? Hence why they do not bother.
Of course one might read this and say, multi device e2ee is possible! Sure, but can you allow for recovery when people inevitably lose their recovery codes at scale? If you really care about this it is not necessary to go with Google.
I stand by my original comment:
The average user does not want it.
> But while homomorphic encryption has a nontrivial cost overhead, it shifts the capability/privacy trade-off to a question of cost. And the cost of homomorphic encryption is rapidly decreasing.
Which doesn't spell out exactly hon "nontrivial" the cost overhead still is.
as a general rule multiplication is the difficult part.
it's hard to accurately quantify what "nontrivial" cost overheads are because they're very application dependent. for example, things that require encrypted control flow are very hard under FHE. so an encrypted hashmap sounds roughly unimplemnetable. but things that do not require encrypted control flow (e.g. many ML applications) are less bad. this can still be quite bad though. for example, relu is trivial in plaintext. it is hard homomorphically, because the trivial way to write it uses private control flow.
Reality: our computers will be used as distributed AI calculators
There are some instances of hand-built cryptographic protocols used in production at Google that use FHE in small doses (e.g., computing a single dot product as part of an interactive protocol), so the big question is whether having a general-purpose tool will expand the feasibility of applying these to other, maybe less critical projects that still want some privacy guarantees but can't afford to hire cryptographers.
It's very useful for things like healthcare data for example but also for products like "home assistants", and it's one of the use cases that the team hiring internally was giving in their job req. I tried to apply too but didn't get it unfortunately, this was a very interesting product to work on imho, congrats to whoever got my job :)
So essentially the headline sells this as work to keep your data private, but really it's work to keep the AI-- which was trained on your code and your writing-- private.
The basic idea of of the project is to remove the need for trust.
I'd expect this to be something like the Google Ad ID: technically separated from what Google considers personal information, but trivially easy to tie back to an individual person and to other information about that person.
They're continually breaking trust by illegally scraping up the internet to feed to their plagiarism machine, which they are now asking us to trust with more data. It's not a compelling arguement.
I think the most immediately useful is checking if a username/password hash appears in a leaked database without revealing which account or password hash is being checked.
If you don’t agree with this model, I’m afraid modern cryptography doesn’t have anything to offer.
I think GP is trying to say something along those lines. Not that encryption isn't trustworthy, but that even with homomorphic encryption you still give up autonomy.
I want to read a whitepaper but all I can find is the tl;dw conference presentation
FHE is traditionally horrifically slow, so it's hard to imagine running anything beyond toy models with it. They list some applications on the original article page, but (presumably) they must be dramatically stripped down in order to run within any reasonable time budget. This is not going to run anything like a Sol/Opus any time soon.
[1]: https://heir.dev/
[0] https://0xparc.org/blog/programmable-cryptography-1
Which is to say, I believe that google is strongly implying the falsehood of "no one at Google can read your stuff."
So I take offense to the term FHE. It's a oxymoron.
The whole thing immidiatly stands out as a sham to build trust where it's gone.
Consider two integers M1 and M2.
Consider RSA with private key (E), public key (D), and public modulus (N).
Encrypt(M, E, N) = mod(pow(M, E), N).
Decrypt(C, D, N) = mod(pow(C, D), N).
mod(Encrypt(M1, E, N) * Encrypt(M2, E, N), N) = mod(Encrypt(M1 * M2, E, N), N).
So, for all RSA encryption, multiplying the ciphertexts results in a ciphertext that is the multiple of the plaintexts. However, unless you can break RSA, you can not determine what numbers you multiplied or what the final multiplied number is.
This is not a fully homomorphic system as it only allows multiplication, but it is a existence proof that you can do operations on ciphertext that apply to the plaintext without being able to recover the plaintext unless you can break the encryption directly.
If you believe the underlying cryptographic hardness assumption of LWE/RLWE/etc, then yes Google cannot see any of the input or output of the model.
It seems like you strongly believe otherwise, but I suspect you don’t have a good reason to, and just find it unbelievable.
Do you think you can distinguish it from noise, if given an implementation and the information an adversary would have access to?
Of course, you not being able to wouldn’t demonstrate that noöne can. But, it seems like if you had a good reason to believe that an adversary can, that would suggest you might have some idea of how they could do so. And, if you do have such an idea, then, if that idea works, it would be important for others to know, and if it doesn’t, it would presumably benefit your understanding to see why it doesn’t.
That's the oxymoron. If it was indistinguishable nothing could be gained.
It's not about me being able to distinguish it. It's the model provider saying they cant, when they can.
I don’t see why you conclude that FHE couldn’t be close to as secure as that. (Like, not information theoretically, but with computationally bounded adversaries.)
In the secret sharing multi-party computation schemes, the individual shares of the secret are random and have no information about the plaintext.
I see no reason that FHE can’t have ciphertexts indistinguishable from noise.
Suppose the plaintext, ciphertext, and key, are each a natural number modulo 5.
The key is selected uniformly at random. The ciphertext is obtained by adding the key to the plaintext (and as a result is also uniform random).
Then the ciphertext is sent to the server. The server only has the ciphertext, which is uniform random. The server then adds some integer mod 5 to the ciphertext, producing a new ciphertext, and sends it back to the user. The user then subtracts their key from the new ciphertext to obtain the new plaintext, which is their original plaintext plus the number the server added.
At no point in this process did the server learn anything about the user’s plaintext.
This is clearly secure.
It is also useless, because just adding a number isn’t a useful thing for a server to do (they may as well just send the user the number and let them add it themselves), but that’s because it is a toy example.
I suppose if mind uploading were possible, then under FHE it would in principle be possible to take the ciphertext and run the computation of “this mind upload of this person reads the data and provides some output”, and then presumably that uploaded person would have the experience of seeing the plaintext? But it wouldn’t be possible to get any information about the plaintext without the key (or enough brute force to find the key, but that’s why we use big enough keys to make this infeasible).
I send this server a question encrypted. It stays encrypted yet the server distinguished my ciphertext enough to produce a coherent reply. That means there was enough information in the ciphertext for the server to perform the inference, even if it was obscured to where it looks indistinguishable, it apparently wasn't.
This doesn't remove trust from the equation, it puts the trust directly on the algorithm. Probably one no one can explain to me like I'm 5. But because it's encrypted I am no longer breaking the law by processing on protected data. I imagine very large contracts await on the other side. Lots of money to be made.
Think about a very simple setting, say a database lookup. I send an index `i` in a database I want to lookup. The server sends back DB[i] or whatever.
In the clear, the server can immediately fetch the correct row. Under FHE, the server does a full scan of the database, and (roughly) for each row will do something like DB[i] * (encrypted selector variable that is 0 or 1 depending on if it is the row you want).
This is actually a baby version of FHE known as "Private Information Retrieval". For it, you (roughly) can design an encryption scheme that supports linear function evaluation. For example, a ciphertext Enc(m) can be paired with a matrix A to produce Enc(Am). You can then encrypt the ith basis vector m := e_i, and view the database as a matrix DB, to get DB * Enc(e_i) = Enc(DB*e_i) = Enc(DB_i). This works, and can be implemented in ~1k LoC, e.g. it is not particularly complicated to practically instantiate (though this basic sketch has some performance issues).
> user-data can be protected from data breaches, but then the service provider cannot provide features that depend on the data, such as spam or virus detection
I think they forgot "or advertising" at the end.
I don't trust Google. I would much prefer to use on-prem or - at most - one of the secure-enclave providers like Tinfoil[1] or Private Mode[2]
[1] https://tinfoil.sh/ [2] https://www.privatemode.ai/
[1] https://sgx.fail/