[colmmacc]

My understanding of encrypted search in FHE is that there can be multiple copies of the same search key, and that search keys aren't simply in-place encrypted versions of themselves - as encrypted fields in a database are - but are mappings embedded in a higher dimensional space that is encrypted.

That reads like sci-fi nonsense, but the "on the metal" result is that a search key will translate to a set of memory locations that are combined to determine the match, and a separate query for the same search key will translate to a different (but potentially overlapping) set of memory locations that produce the same result.

[MBCook]

Do I have this right?

If the server could actually decode things it would’ve gotten something that could be decrypted into let’s say 15 phone numbers. A little bit like if they were hashed, to simplify.

So the answer the server returns isn’t who the phone number belongs to, it’s who those 15 phone numbers belong to.

And then the client can decrypt it and just get the one that it cares about.

But unlike if you were just doing hash buckets no one who saw the data going back-and-forth could actually understand any of it. Correct?

Is this only really good for data to look up cases? I had thought homomorphic encryption could be used to do actual calculations, at least certain kinds.

[ElFitz]

> I had thought homomorphic encryption could be used to do actual calculations, at least certain kinds.

Well yes. There was this:

- https://news.ycombinator.com/item?id=21638639

- https://news.ycombinator.com/item?id=31933995

- https://azeemba.com/posts/homomorphic-encryption-with-images...

And quite a few more.

[fragmede]

Theoretically it can, but the tech isn't quite there yet, so we don't know for sure.

[GTP]

AFAIK (but my knowledge is 2/3 years out of date) the problem with general computation is that current schemes are still too slow for parctical use. But recent developments give hope that it could be doable in the future.