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Homomorphic encryption

en.wikipedia.org

51–60 of 86 posts

Re: Homomorphic encryption

#52

Could a fully homomorphic cpu architecture with fully encrypted cache be immune to Spectre and similar side channel attacks? Could this be tested on an FPGA?

Unfortunately, FHE doesn't work this way. You're operating on encrypted data, so performing some branched operations doesn't work due to the security (IND-CPA) security.

IE: You have a value that you need to do `if then else `

Problematically, if that condition could work, then it would violate the confidentiality of the encrypted value, thus breaking the CPA security. Now there are some workarounds and methods to getting around this problem sometimes, but in many cases it's not possible.

Re: Homomorphic encryption

#54

Why do people always talk about arbitrary computation in relation to homomorphic encryption? What I really want is a homomorphic encryption system which allows me to arbitrarily slice and concatenate strings without knowing their contents. This would be immensely useful for implementing end-to-end encrypted collaborative editing of documents. Is homomorphic encryption there yet?

I'm dying for this. My team builds ML models on text corpora. Most of this data is sensitive. My company has very strict data privacy policies and it's a pain to even share the data with other teams in the department. I've made it part of my long-term goals to facilitate secure sharing of sensitive data across the organization. Numerical data seems to be the easiest to anonymize (randomized response, etc), but I have yet to find any techniques for text other than generating synthetic data.

Re: Homomorphic encryption

#55
post #52

Could a fully homomorphic cpu architecture with fully encrypted cache be immune to Spectre and similar side channel attacks? Could this be tested on an FPGA?

Unfortunately, FHE doesn't work this way. You're operating on encrypted data, so performing some branched operations doesn't work due to the security (IND-CPA) security. IE: You have a value that you need to do `if then else ` Problematically, if that condition could work, then it would violate the confidentiality of the encrypted value, thus breaking the CPA security. Now there are some workarounds and methods to ge…

So any unit of work in the FHE scenario is necessarily a basic block with no branching ?

Re: Homomorphic encryption

#56

Why do people always talk about arbitrary computation in relation to homomorphic encryption? What I really want is a homomorphic encryption system which allows me to arbitrarily slice and concatenate strings without knowing their contents. This would be immensely useful for implementing end-to-end encrypted collaborative editing of documents. Is homomorphic encryption there yet?

You can do this with a TFHE implementation, if I understand your use case correcltly. You encrypt bits and then you can operate/manipulate on those individual encrypted bits.

I referenced NuFHE in a comment, but you should give it a try and see if it will do what you're wanting. See https://github.com/nucypher/nufhe/. We also have a discord channel where you can ask questions on using it in the #nufhe channel -- https://discord.gg/rmSafk

Re: Homomorphic encryption

#57
post #55
post #52

Earlier quoted context omitted.

Unfortunately, FHE doesn't work this way. You're operating on encrypted data, so performing some branched operations doesn't work due to the security (IND-CPA) security. IE: You have a value that you need to do `if then else ` Problematically, if that condition could work, then it would violate the confidentiality of the encrypted value, thus breaking the CPA security. Now there are some workarounds and methods to ge…

So any unit of work in the FHE scenario is necessarily a basic block with no branching ?

In most situations, yes. Like I said there are methods and exceptions, but it's complex to get into.

Re: Homomorphic encryption

#58
post #54

Why do people always talk about arbitrary computation in relation to homomorphic encryption? What I really want is a homomorphic encryption system which allows me to arbitrarily slice and concatenate strings without knowing their contents. This would be immensely useful for implementing end-to-end encrypted collaborative editing of documents. Is homomorphic encryption there yet?

I'm dying for this. My team builds ML models on text corpora. Most of this data is sensitive. My company has very strict data privacy policies and it's a pain to even share the data with other teams in the department. I've made it part of my long-term goals to facilitate secure sharing of sensitive data across the organization. Numerical data seems to be the easiest to anonymize (randomized response, etc), but I have…

Hi, I've been replying to other people in this thread. I work at NuCypher doing some research and cryptography engineering. I work on Proxy Re-Encryption and Fully Homomorphic Encryption.

Do you mind sending me an email with your use case and needs? I'd love to have a chat with you.

john@nucypher.com

Re: Homomorphic encryption

#59
post #52

Could a fully homomorphic cpu architecture with fully encrypted cache be immune to Spectre and similar side channel attacks? Could this be tested on an FPGA?

Unfortunately, FHE doesn't work this way. You're operating on encrypted data, so performing some branched operations doesn't work due to the security (IND-CPA) security. IE: You have a value that you need to do `if then else ` Problematically, if that condition could work, then it would violate the confidentiality of the encrypted value, thus breaking the CPA security. Now there are some workarounds and methods to ge…

Thanks for your explanation. When I read [1]:

> A cryptosystem that supports arbitrary computation on ciphertexts is known as fully homomorphic encryption (FHE). Such a scheme enables the construction of programs for any desirable functionality, which can be run on encrypted inputs to produce an encryption of the result

I thought that meant the program itself could be fully encrypted, but after a second look it seems that it is just the inputs that are encrypted. Still, other areas of the wiki talk about support for boolean gates and even arbitrary gates. I don't know what to think, but it is motivating me to revisit coding theory :-)

[1] https://en.m.wikipedia.org/wiki/Homomorphic_encryption#Fully...

Re: Homomorphic encryption

#60

Why do people always talk about arbitrary computation in relation to homomorphic encryption? What I really want is a homomorphic encryption system which allows me to arbitrarily slice and concatenate strings without knowing their contents. This would be immensely useful for implementing end-to-end encrypted collaborative editing of documents. Is homomorphic encryption there yet?

So you want to slice and concatenate strings without you yourself and any other collaborators knowing what the string is? what about hashing each word? you could slice and concat on whitespace boundaries if that's the case.

i'm not sure how this helps e2e encrypted collaborative editing though. why not just use asymmetric encryption? what am i missing?

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