‹ BackHN Continuity

Thread

Keys Not Included: recovering the signing keys for US driver's license barcodes

289 points · 152 comments · Ryan5453

  1. bzmrgonz · · focus · HN ↗
    It baffles that people think it's a bad thing to disclose a public key. That's their purpose actually. Sure we now have the post quantum computer threat, and some state actors are harvesting keys, but quantum computer is going to disrupt so much, that Id verification won't even matter really.
    1. morsch · · focus · HN ↗
      Think about it, the key analogy is just terrible. In the origin domain, losing a key is always bad, and making a key available to all is a non sequitur.

      It's not like non-technical people understand asymmetric cryptography. Or even technical people, for that matter.

      Maybe we should refer to the public key as an address, and the private key is just a password again. You can send stuff, securely, to an address. And you can verify the sender when you have their address (ie check the signature).

      1. fc417fc802 · · focus · HN ↗
        The key analogy is perfect for the private key and for symmetric keys. Publishing those is always bad and means you need to rekey immediately just like losing a traditional physical key to a secure building would.

        The public counterpart is tricky to name but I think attaching "public" to it makes the intended usage plenty clear. There isn't really a physical counterpart unless you consider maybe those machines that check for counterfeit cash but even that's not a great fit because the pubkey is simultaneously analogous to a lock box.

        1. tialaramex · · focus · HN ↗
          Not quite. The analogy works for secret keys (what you're calling "symmetric keys") but a private key is unlike real world key analogies because as you'll quickly discover if you deploy real world keys in a high security environment people can examine the lock to figure out the correct key. The whole point of private keys is that this cannot work in a public key system. That step does not exist.

          It is true that publishing your private key is bad but you'd hope the name makes that pretty clear. Despite the way I remember (U2's "The Fly" lyrics, "A secret is something that you tell one other person, so I'm telling you, child") people generally do not understand that the whole point of secrets is that at least two parties know, which means you might always be betrayed by somebody you think is keeping your secret. For a private key it's easy, don't tell anybody, nobody knows, you can't be betrayed, done.

          For example Hacker News learns my password to this web site every single time I sign in because that's just a secret. We've known how to do better for decades but only a handful of systems I use (e.g. Google) do so and all of them have a "traditional" password option which is like discovering your aeroplane still has a smoking section in 2026.

          1. bigfishrunning · · focus · HN ↗
            > For example Hacker News learns my password to this web site every single time I sign in because that's just a secret.

            I don't know the details of the login system for Hacker News, but i would expect they learn "a hash of your password and some salt" for every login, and your password isn't just transmitted to them. If they're doing things correctly, they're only storing a hash of your password, and can't work backward to get it -- that's a big If, and lots of places get it wrong.

            1. DaSHacka · · focus · HN ↗
              I've never actually found a site that computes the hash client-side and sends the finished hash to the server, the vast majority just send the regular password to the backend to be hashed and compared (and HN is no exception).

              And if you think about it, there's really no advantage to sending the hash every time anyway. An attacker that MITMs your traffic once can just resend the static post-computed hash to the backend anyway.

              The only advantage would be preventing an attacker from seeing a password string you may re-use for other sites, but so long as it's unique for HN alone (surely we all use password managers on here? :-) ) it doesn't matter.

Open on Hacker News to reply ↗

Unofficial Hacker News client; not affiliated with Y Combinator.