4 ms·

Hmm, very interesting! > The tools to do this simply don't currently exist, but GnuNet has developed an approach to convergent encryption of keywords which poi

by rwl 13y ago

Hmm, very interesting! > The tools to do this simply don't currently exist, but GnuNet has developed an approach to convergent encryption of keywords which points to how one might implement this in an email system. What you describe sounds a lot like "fully homomorphic encryption" (given my pretty amateur understanding of that term). Is the technique you describe one that could be layered on top of PGP? Or does it need an entirely different crypto scheme?

wtbob 13y ago
> What you describe sounds a lot like "fully homomorphic encryption" (given my pretty amateur understanding of that term). Well, not really from a technical standpoint. Homomorphic encryption is about me encrypting 1 and 2, handing you #x8495 and #x7835, you executing (homomorphic-add #x8495 #x7835) to get #x1932 and handing it back to me, whereupon I'm able to decrypt it to get 3. You can imagine why this could be cool: there's the potential for someone to be able to perform work on one's behalf without compromising one's privacy (imagine TurboTax working on encrypted data, with Intuit unable to know what one's finances are). The technique I describe is different, but it does enable a similar end result: someone else can run an indexing/search engine on my behalf, and I can consult it to search my data without ever revealing that data to the engine-runner. The engine isn't really able to perform any calculations though. > Is the technique you describe one that could be layered on top of PGP? Well, it would work in parallel to PGP (or any other data-at-rest scheme). PGP would encrypt the plaintext, and this would be used to index the plaintext. GNUnet uses this technique so that two different people can arrive at the same encryption for keyword searches (which of course has vulnerabilities, since one's adversary can perform those same searches); I use it so that the same person at two different times can index and search by keyword, and protect against an adversary through the use of a secret hash key.

by rwl 13y ago

wtbob 13y ago

> What you describe sounds a lot like "fully homomorphic encryption" (given my pretty amateur understanding of that term). Well, not really from a technical standpoint. Homomorphic encryption is about me encrypting 1 and 2, handing you #x8495 and #x7835, you executing (homomorphic-add #x8495 #x7835) to get #x1932 and handing it back to me, whereupon I'm able to decrypt it to get 3. You can imagine why this could be cool: there's the potential for someone to be able to perform work on one's behalf without compromising one's privacy (imagine TurboTax working on encrypted data, with Intuit unable to know what one's finances are). The technique I describe is different, but it does enable a similar end result: someone else can run an indexing/search engine on my behalf, and I can consult it to search my data without ever revealing that data to the engine-runner. The engine isn't really able to perform any calculations though. > Is the technique you describe one that could be layered on top of PGP? Well, it would work in parallel to PGP (or any other data-at-rest scheme). PGP would encrypt the plaintext, and this would be used to index the plaintext. GNUnet uses this technique so that two different people can arrive at the same encryption for keyword searches (which of course has vulnerabilities, since one's adversary can perform those same searches); I use it so that the same person at two different times can index and search by keyword, and protect against an adversary through the use of a secret hash key.