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.
The public part of it would be the RSA pubkey, likely linked with an identifier such as the SHA-256 hash of the email. You could quite easily have that ledger public and it would take millennia to crack any of the emails, much easier to use fuzzing with common words and names than trying wasting computing power for a single email. The whole point of blockchain is that it's an immutable public ledger which would actually suit this idea quite well.
This is solving a problem we DO have, albeit in a different way. Email is ancient, the protocol allows you to self identify as whoever you want. Let's say I send an email from the underworld (server ip address) claiming I'm Napoleon@france (user@domain), the only reason my email is rejected is because the recipient knows Napoleon resides on the server France, not underworld. This validation is mostly done via tricky DNS hacks and a huge part of it is built on top of Google's infrastructure. If for some reason Google decides I'm not trustworthy, then it doesn't matter if I'm actually sending Napoleon's mail from France, it's gonna be recognized as spam on most servers regardless.
A decentralized chain of trust could potentially replace Google + all these DNS hacks we have in place. No central authority gets to control who is legitimate or not. Of all the bs use cases of block chain I think this one doesn't seem that bad. It's building a decentralized chain of trust for an existing decentralized system (email), which is exactly what "block chain" was originally designed for.