this post was submitted on 02 May 2024
30 points (96.9% liked)
Privacy
31175 readers
919 users here now
A place to discuss privacy and freedom in the digital world.
Privacy has become a very important issue in modern society, with companies and governments constantly abusing their power, more and more people are waking up to the importance of digital privacy.
In this community everyone is welcome to post links and discuss topics related to privacy.
Some Rules
- Posting a link to a website containing tracking isn't great, if contents of the website are behind a paywall maybe copy them into the post
- Don't promote proprietary software
- Try to keep things on topic
- If you have a question, please try searching for previous discussions, maybe it has already been answered
- Reposts are fine, but should have at least a couple of weeks in between so that the post can reach a new audience
- Be nice :)
Related communities
Chat rooms
-
[Matrix/Element]Dead
much thanks to @gary_host_laptop for the logo design :)
founded 4 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Yes, but the information would need to be computationally verifiable for it to be meaningful - which basically means there is a chain of signatures and/or hashes leading back to a publicly known public key.
One of the seminal early papers on zero-knowledge cryptography, from 2001, by Rivest, Shamir and Tauman (two of the three letters in RSA!), actually used leaking secrets as the main example of an application of Ring Signatures: https://link.springer.com/chapter/10.1007/3-540-45682-1_32. Ring Signatures work as follows: there are n RSA public keys of members of a group known to the public (or the journalist). You want to prove that you have the private key corresponding to one of the public keys, without revealing which one. So you sign a message using a ring signature over the 'ring' made up of the n public keys, which only requires one of n private keys. The journalist (or anyone else receiving the secret) can verify the signature, but obtain zero knowledge over which private key out of the n was used.
However, the conditions for this might not exist. With more modern schemes, like zk-STARKs, more advanced things are possible. For example, emails these days are signed by mail servers with DKIM. Perhaps the leaker wants to prove to the journalist that they are authorised to send emails through the Boeing's staff-only mail server, without allowing the journalist, even collaborating with Boeing, to identify which Boeing staff member did the leak. The journalist could provide the leaker with a large random number r1, and the leaker could come up with a secret large random number r2. The leaker computes a hash
H(r1, r2)
, and encodes that hash in a pattern of space counts between full stops (e.g. "This is a sentence. I wrote this sentence." encodes 3, 4 - the encoding would need to limit sentence sizes to allow encoding the hash while looking relatively natural), and sends a message that happens to contain that encoded hash - including to somewhere where it comes back to them. Boeing's mail servers sign the message with DKIM - but leaking that message would obviously identify the leaker. So the leaker uses zk-STARKs to prove that there exists a message m that includes a valid DKIM signature that verifies to Boeing's DKIM private key, and a random number r2, such that m contains the encoded form of the hash with r1 and r2. r1 or m are not revealed (that's the zero-knowledge part). The proof might also need to prove the encoded hash occurred before "wrote:" in the body of the message to prevent an imposter tricking a real Boeing staff member including the encoded hash in a reply. Boeing and the journalist wouldn't know r2, so would struggle to find a message with the hash (which they don't know) in it - they might try to use statistical analysis to find messages with unusual distributions of number of spaces per sentence if the distribution forced by the encoding is too unusual.Great summary. Thanks for this.