[HN Gopher] A JPEG Image Compression Service Using Part Homomorp...
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A JPEG Image Compression Service Using Part Homomorphic Encryption
Author : keepamovin
Score : 25 points
Date : 2025-03-03 09:35 UTC (3 days ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| pogue wrote:
| What would you use this for?
| 77pt77 wrote:
| Compressing images into jpeg without anyone else ever seeing
| them.
|
| I personally would prefer something like Homomorphic encryption
| for say sql queries on a database that the server can never
| read.
| tgv wrote:
| There's no information in the repo, but I suppose this means
| jpeg compression of an encrypted image without decryption,
| right?
| mystified5016 wrote:
| Yes. Homomorphic encryption means that you can do math to
| the encrypted file to produce a _new_ encrypted file. The
| operator doing the math cannot read either version, but the
| owner of the original file can.
| pogue wrote:
| Without anyone ever seeing them?
| perching_aix wrote:
| As a technological demonstration of homomorphic encryption and
| its benefit.
| cogman10 wrote:
| I'm having a hard time wrapping my head around how you'd do
| homomorphic encryption securely (particularly FHE).
|
| Like, for example, let's say I want to farm out word counts
| to the cloud. Wouldn't the information required to identify
| what a "word" is require the running software to be able to
| see breaks/periods/etc? Doesn't that leak information about
| the cyphertext? How does it stop someone from writing
| software that, for example, maps out the position of all the
| a's, then b's, then c's, etc in a cyphertext and MITMing it?
| perching_aix wrote:
| I think the idea is that you would never get to know the
| answer to those individual questions, or any questions
| really; you'd be producing an encrypted blob of a response
| that supposedly has the answer and then just pass that
| onward.
|
| Unfortunately the mathematical details escape me as well.
| Maybe one day I'll set aside some time to look into it.
| fragmede wrote:
| That wouldn't be FHE, for the reason you identified.
| Outside of a tiny number of algorithms, homomorphic
| encryption doesn't usefully generalize to something as
| generic as word counting of arbitrary text like that.
| Production use of FHE is really limited. Probably the most
| well known application is by Apple for phone number lookup,
| where they're able to get the caller id for a phone number
| without knowing the phone number, basically.
| uniq7 wrote:
| I don't know what's the current state of the art, I only
| read Craig Gentry, 2009 [1] (the first FHE scheme
| proposed), but the main idea there is that an untrusted
| agent can perform operations on the encrypted data (i.e.,
| addition and multiplication) and obtain an encrypted result
| that cannot be read but can be sent to the user.
|
| Since the scheme is asymmetric, the untrusted agent can
| also encrypt new data with the public key, meaning that
| they can do things like: `return encrypt(x) +
| encrypted_data_from_user * encrypt(y)`
|
| I guess this alone doesn't let the untrusted agent evaluate
| a boolean condition or run an algorithm like the one you
| proposed, but they can at least run encrypted data through
| a neural network and send the encrypted output to the user.
|
| [1] https://www.cs.cmu.edu/~odonnell/hits09/gentry-
| homomorphic-e...
| alberth wrote:
| "Compression" and "Encryption" seem like two words I wouldn't
| expect in the same sentence.
|
| Wouldn't you compress the file independently ... regardless of
| anytype of encryption (homomorphic or not).
| Almondsetat wrote:
| This is image compression, which uses visual tricks, not simple
| binary file compression
| alberth wrote:
| Isn't a JPEG already compressed.
|
| I'm confused.
| Almondsetat wrote:
| The service is taking an encrypted image and compressing it
| without decrypting it
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