Proton Mail, the leading privacy-focused email service, is making its first foray into blockchain technology with Key Transparency, which will allow users to verify email addresses. From a report: In an interview with Fortune, CEO and founder Andy Yen made clear that although the new feature uses blockchain, the key technology behind crypto, Key Transparency isn’t “some sketchy cryptocurrency” linked to an “exit scam.” A student of cryptography, Yen added that the new feature is “blockchain in a very pure form,” and it allows the platform to solve the thorny issue of ensuring that every email address actually belongs to the person who’s claiming it.
Proton Mail uses end-to-end encryption, a secure form of communication that ensures only the intended recipient can read the information. Senders encrypt an email using their intended recipient’s public key – a long string of letters and numbers – which the recipient can then decrypt with their own private key. The issue, Yen said, is ensuring that the public key actually belongs to the intended recipient. “Maybe it’s the NSA that has created a fake public key linked to you, and I’m somehow tricked into encrypting data with that public key,” he told Fortune. In the security space, the tactic is known as a “man-in-the-middle attack,” like a postal worker opening your bank statement to get your social security number and then resealing the envelope.
Blockchains are an immutable ledger, meaning any data initially entered onto them can’t be altered. Yen realized that putting users’ public keys on a blockchain would create a record ensuring those keys actually belonged to them – and would be cross-referenced whenever other users send emails. “In order for the verification to be trusted, it needs to be public, and it needs to be unchanging,” Yen said.
Curious if anyone here would use a feature like this? It sounds neat but I don’t think I’m going to be needing a feature like this on a day-to-day basis, though I could see use cases for folks handling sensitive information.
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It sounds overcomplicated, is there really a need for the blockchain aspect? Could the same security be provided by a simpler method (like how keybase has their identity proofs?) but better to have it and not need it than need it and not have it ig
Right here:
The benefit of doing this with a blockchain instead of a privately held and maintained database is that the latter can be compromised, and you just have to trust “whoever” is maintaining that private database. Blockchain means that the ledger is distributed to many nodes, and any post-entry modification to that chain would be instantly recognized, and marked invalid by the other nodes operating the chain. Besides that, when you’re looking up a public key for a recipient on such a blockchain, you would be looking it up at a number of nodes large enough that in order for a malicious entry to come through, they would all have to be modified in the same way, at the same time, and you would have to be asking before the change got flagged. Poisoning blockchain data like this is simply not possible; that’s what makes this an especially secure option.
But it’s not public. It’s a private blockchain. The immutable ledger aspect only matters if everyone can see the ledger. Otherwise we take at face value all of the things you said. Assume they run one node and that one node is compromised by a malicious actor. The system fails. Extend it to a limited number of nodes all controlled by SREs and assume an SRE is compromised (this kind of spearphishing is very common). The system fails again.
Sure, you can creatively figure out a way to manage the risks I’ve mentioned and others I haven’t thought of. The core issue, that it’s not public, still remains. If I’m supposed to trust Proton telling me the person I’m emailing is not the NSA pretending to be that person (as the Proton CEO suggested), I need to trust their verification system.
It’s. In. Beta. Of course it’s not being offered to the general public yet. It’s likely that there are very many beta nodes, in order to test scalability. When it’s out of beta, you drop the beta chain and start a new one.
Did we read the same article? Emphasis mine.
I’m not interested until it’s public. Additionally, building out the chain then dropping it to rebuild a new public one is rewriting history, which violates the whole “immutable” part of “immutable ledger.”
There is obviously an invasion of shills.
Its. In. Beta.
Untestable security claims for sensitive information are useless. I’m a huge fan of Proton and I’m excited to test this but only once the blockchain is public. Until then there is no way to verify the trust so there is no trust.
If you disagree, I might have something for you. I’ve got the strongest financial encryption known to man on top of the best transit system ever that makes it super easy to do stuff. It’s all based on blockchain, of course. Just give me your credit card info and bank details. It’s in beta so I won’t let you audit it, but unless you’re shilling you don’t have a problem with that.
Its. In. Betaaaaaa
This is good for blockchain.
Beta doesn’t negate security fundamentals ¯\_(ツ)_/¯
Context matters:
It’s not rewriting history. We’re talking about validation of public keys. The exact same information can be added to a public non-beta chain, to satisfy the concerns about security that would come from maintaining a previously private beta chain into production.
… which gives a timing attack and the ability for bad actors to impersonate someone. I agree with you that, once public, this is a good idea. You cannot convince me that this is a good idea if done privately because there is no way to trust but verify, especially in the highly sensitive contexts they want trust in.
If it’s not public, I won’t trust it. You trust it blindly because it’s in beta. We’re not going to come to an agreement over these mutually exclusive positions.
I don’t “trust it blindly” because it’s in beta - I understand that it’s a work in progress because it’s in beta. Jesus christ you people and your fucking tinfoil hats.
Your only response to valid criticism about the lack of verification is pointing to the state of development as if that magically washes away all of the criticism. It doesn’t.
While I do have many tinfoil hats, basic fucking trust measures do not require me to pull them out. This is cryptography 101 shit not anything complicated.
And on the flip side, you cannot delete data that is sensitive or entered incorrectly. Blockchain evangelists assume these things will never happen.
As long as there is an appropriate method for adding a legitimate entry to the chain, incorrectly entered data can be handled by appending corrected data on to the chain, and marking the error as such. Sensitive data, in this case, would be along the lines of “I accidentally added my private key instead of my public key.” The action necessary here is the same as if I published my private key anywhere: stop using that key pair and generate a new one.
So at the point a private key becomes compromised, then what? If you have to start from scratch, then a malicious entity could start from scratch too. And if that’s the case, there is no security benefit.
This part:
And if there’s not, then…? Because that was my question.
Well, if there’s not, then the whole thing would never work at all.
Seems like we have found a problem.
Because the Proton blockchain is currently private, the keys they are currently adding could easily be affected by a man in the middle attack. And there would be no way to invalidate those keys for any of the affected users, they would just have to… What?
Ditch their email addresses?
Appeal to a higher authority?
PGP solved this a long time ago, but it is difficult to make it user friendly enough for non-technical people to understand and adopt it.
How many people have verified how many people’s identity with PGP signatures? Also I’m willing to bet a horribly shocking amount of people would just accept a new key from someone (not necessarily sign it) and trust them regardless.
People evangelizing this new, untested, private technology already saying it would be automatic, so everything would be easy to use. And that’s the problem, isn’t it… If it’s all automatic, nothing is being verified.
By the way, PGP already has this.
https://stackoverflow.com/questions/3591342/how-to-prevent-a-man-in-the-middle-attack-in-case-of-a-compromised-server
Yeah these issues are definitely not new, but replacing “I trust the people who sign/verify my keys” versus “I trust the blockchain” is not too far off. What rules are going to be in place for peers to validate entries to the blockchain and independently reach enough concensus to achieve true decentralization?
To be clear, I’m not saying this solution is better or worse than PGP, I just don’t believe PGP works well for creating a web of trust.