11–20 of 22 posts
Was there ever a followup blogpost?
http://outsourcedbits.org/2012/06/26/applying-fully-homomorp...
http://outsourcedbits.org/2012/09/29/applying-fully-homomorp...
> Just try converting that into a circuit
Hmm. I think this article is a little behind the times. Loops are not a problem with Homomorphic encryption, as we can create circuits that work exactly like a transistor-based CPU.
In fact, I've got an implementation of one that I've been working on here: https://github.com/mmastrac/oblivious-cpu
The trick to making this work is that you may not know how long the computation is going to take, so you need to either add a set number of iterations to run (ie: clock cycles), or send back encrypted updates as you run to give your trusted computer a chance to determine when the calculation has finished.
http://www.americanscientist.org/issues/pub/2012/5/alice-and...
https://en.m.wikipedia.org/wiki/Homomorphic_encryption
Oh hey, this is something I've actually done some real work on! > Just try converting that into a circuit Hmm. I think this article is a little behind the times. Loops are not a problem with Homomorphic encryption, as we can create circuits that work exactly like a transistor-based CPU. In fact, I've got an implementation of one that I've been working on here: https://github.com/mmastrac/oblivious-cpu The trick to ma…
> I mean, it’s not impossible to unroll loops (if you know the maximum number of iterations), but the resulting circuit is not likely to be practical. Moreover, this isn’t purely an issue with the use of circuits, but rather with the use of encrypted data. No matter what computational model you employ, you’re always going to have difficulty with things like control flow changes that depend on input data that the executing party can’t see.
If you want to add in interaction, then you have other far more efficient schemes for achieving such FHE, like garbled circuits
Oh hey, this is something I've actually done some real work on! > Just try converting that into a circuit Hmm. I think this article is a little behind the times. Loops are not a problem with Homomorphic encryption, as we can create circuits that work exactly like a transistor-based CPU. In fact, I've got an implementation of one that I've been working on here: https://github.com/mmastrac/oblivious-cpu The trick to ma…
One limitation of Homomorphic encryption, as far as I can see, is that there is no way for the encrypted program to choose to communicate some data in the clear. Which means it can't be used to allow an untrusted party to run your encrypted server, and have the server communicate with parties that it doesn't trust. Which is what most servers do. Unless I'm mistaken, or there has been an advance?
There is no encrypted program, there is encrypted data. You can operate on this data, and it will reflect on the plaintext after decryption. I think what you're thinking about is functional encryption?
Is it practical on an intel cpu ?
Earlier quoted context omitted.
I'm not thinking of functional encryption. I thought I'd read somewhere a plan to use homomorphic encryption with an encrypted program by simply applying an interpreter to it.
You're not thinking of Indistinguishability Obfuscation per chance? https://blog.cryptographyengineering.com/2014/02/21/cryptogr... seems an interesting article.
One limitation of Homomorphic encryption, as far as I can see, is that there is no way for the encrypted program to choose to communicate some data in the clear. Which means it can't be used to allow an untrusted party to run your encrypted server, and have the server communicate with parties that it doesn't trust. Which is what most servers do. Unless I'm mistaken, or there has been an advance?
Can you tell us what do you mean by "encrypted program"? Do you mean that if all operations of a universal Turing machine were homomorphic then you can encryt the code with a hard-coded input and get an encrypted output? Can you also elaborate on your server example? I don't understand what you are trying to do. (Whats an "encrypted server"?
What you'd like to be able to do, is something like encrypt the code of a tor node in such a way that it could be run by an untrusted hosting provider, without breaking the security of tor.
Earlier quoted context omitted.
There is no encrypted program, there is encrypted data. You can operate on this data, and it will reflect on the plaintext after decryption. I think what you're thinking about is functional encryption?
Could you spare a minute to comment of the current state of functional encryption? Is it practical on an intel cpu ?