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Comment by ams6110 | Hacker News Reader

I've worked in support of computing clusters that are widely used by researchers. By far the most common problem people had with using these systems was grokking ssh keys. Masters and PhD Computer Science people are routinely baffled by them, provide their private keys instead of their public keys, or provide both, etc.

People in general just don't get public/private key pairs. Any solution that requires any awareness or handling of the keys by the user is a non-starter. Sorry to sound negative but after a couple of decades of observation I'm convinced this will never change.

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Yet, if you call a public key/private key a lock/key respectively, then a lot more people would immediately get the concept.

"You send him a copy of your lock which he uses to lock a package and return it to you. Then only your key can open it!"

You immediately fix the problem of people sending their key, because people know keys are important and shouldn't be handed out to just anyone.

The PKI people are brilliant. Their communication skills, not so much.

I've always wondered why we couldn't just call public keys locks. That would avoid so much confusion for first-time users.

Probably because the analogy breaks down so fast.

"And to prove he sent the package, he locks it with his key and then you use your copy of his lock to open it so that you know it's from him!"

It's a useful analogy for one specific use of public/private keys. But it doesn't capture the full spirit, which may lead to more confusion than just using no analogy.

It's not true in general that public-key encryption and digital signatures are inverse operations. (RSA has that property, but there are plenty of other algorithms that don't work that way.)

If you're writing for a lay audience that doesn't care about things like modular arithmetic, there's no reason to conflate the two operations. Just say encryption is like keys and locks, and signing is like... well... a signature.

So this public key is like a lock and that public key is not like a lock. Got it.

After reading 'Why King George III Can Encrypt'[1] I really started hoping that something came of it. The metaphors they used seemed much more straightforward.

[1] https://freedom-to-tinker.com/blog/randomwalker/why-king-geo...

> provide their private keys instead of their public keys

I see this quite frequently from developers, as well. Hands down one of the worst design decisions of OpenSSH was to make private keys tab complete before public keys.

It will never change as long as using public/private key pairs is something exotic most people rarely use. I was baffled too when I first started using ssh keys, but today it's second nature. I get how they work, at least on a theoretical level. And I think most of us here on HN are like that. This isn't about being smart or of a mathematical bent, it just comes down to practice.

If you read to the end, you'll discover the author comes to the same conclusion.

It could work, but it's a bit hard to wrap your head around public/private keys. Cryptographic keys has to either be an everyday encounter or something we never do. I don't think such a weird thing can be anything in between.

Yup, it's not really specific to SSH. The same problems occur using SSL X509 client certificates. Non-technical users will get confused unless they have a smart card/token that secures their private key.

I've seen this too. I've literally had (otherwise very smart!) people email me their PPK files (Putty Private Keys)! (Userify does help a lot with this now, however.)

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