5 ms·

It is a huge improvement. Nobody can impersonate the bank without the bank's cooperation. When cooperation ends, so does the ability to impersonate. This is no

It is a huge improvement. Nobody can impersonate the bank without the bank's cooperation. When cooperation ends, so does the ability to impersonate. This is not the case with any mechanism that requires you to hand over your keys. Not even issuing a revocation effectively terminates use of a compromised key.

xorcist 12y ago
There is no practical improvement here. What does it matter security-wise if the HSM module (which is what banks use) physically sits on Cloudflare premises or off Cloudflare premises? It's still connected to the same equipment. It does matter for a variety of other reasons, for example what security clearances are required to work there, but it does not matter much for security.
- tokenizerrr 12y ago
  Now cloudflare employees will have no possible access to the private key, nor do intruders who break into the cloudflare servers. This keeps the bank in full control of who has access to the key, they can stop responding to signing requests at any time and then keep trusting the key on their own servers in the future.
  - xorcist 12y ago
    Cloudflare employees will have no access to the key inside a HSM even if it colocated on their premises. That's why you use them. Please summarize the differences between this protocol and PKCS instead of downvoting.
    - nknighthb 12y ago
      Without a system like this, you would require many HSMs physically co-located with every server around the world, you would be trusting entirely in the ability of the HSM to withstand prolonged physical attack/analysis by a highly-resourced adversary (I'd consider this security suicide), and you would still not have the ability for the bank to cut off impersonation at any moment. I have, incidentally, downvoted your comment, because you are complaining about downvotes. Don't do that.
      - xorcist 12y ago
        A HSM does not need to be physically attached to "every server around the world". This is what they've built here, yet another network attached HSM, but not by following the standard PKCS protocols. (On the subject of HSM physical attacks: That's another issue altogether, and does not stop at the HSM. But normally that's not an attack you defend against, because you have the relevant contractual obligations against your infrastructure provider.) I promise not to ask about downvotes again. But the question was honest; if I'm wrong I want to know it.
        nknighthb 12y ago
        If there's an established "correct" solution to this problem, why hasn't anyone pointed to it directly, and why didn't the banks use it? Could you point to some credible expert commentary (as opposed to anonymous noise on HN) describing why what CloudFlare has done here is wrong?
        xorcist 12y ago
        Why do you think banks don't use HSMs? They do. They are off the shelf products. If it's the "correct" solution to your problems depends on what your problem actually is. In this case Cloudflare apparently thought it was the right solution in theory but developed their own instead of using existing products and/or standards. I don't know the rationale for this, but I'd be interesting in knowing more, as you can read in my comment above. I don't know why I should point out that Cloudflare did the wrong thing. Perhaps you are confusing me with someone else? What I did say is that the alternative to the described solution is to use a HSM, and that their solution should offer equivalent security.
        nknighthb 12y ago
        You said "There is no practical improvement here.". If CloudFlare has not done something wrong, then why did you say that? Before you answer that question, remember: A hypothetical solution is not a practical solution. A practical solution is always a practical improvement over the case where there was no existing practical solution offered. And before you say "They should have used HSMs", remember: CloudFlare has made it clear that HSMs being under their control was simply not an option. It was clear in their first blog post, and just for good measure, it was made absolutely explicit in an interview with Ars[0] where CloudFlare's CEO said "there’s no vault we can ever build that they’ll trust us with their SSL keys". So, how is there no practical improvement? [0] http://arstechnica.com/information-technology/2014/09/in-depth-how-cloudflares-new-web-service-promises-security-without-the-key/ http://arstechnica.com/information-technology/2014/09/in-dep...

xorcist 12y ago

There is no practical improvement here. What does it matter security-wise if the HSM module (which is what banks use) physically sits on Cloudflare premises or off Cloudflare premises? It's still connected to the same equipment. It does matter for a variety of other reasons, for example what security clearances are required to work there, but it does not matter much for security.

tokenizerrr 12y ago
Now cloudflare employees will have no possible access to the private key, nor do intruders who break into the cloudflare servers. This keeps the bank in full control of who has access to the key, they can stop responding to signing requests at any time and then keep trusting the key on their own servers in the future.
- xorcist 12y ago
  Cloudflare employees will have no access to the key inside a HSM even if it colocated on their premises. That's why you use them. Please summarize the differences between this protocol and PKCS instead of downvoting.
  - nknighthb 12y ago
    Without a system like this, you would require many HSMs physically co-located with every server around the world, you would be trusting entirely in the ability of the HSM to withstand prolonged physical attack/analysis by a highly-resourced adversary (I'd consider this security suicide), and you would still not have the ability for the bank to cut off impersonation at any moment. I have, incidentally, downvoted your comment, because you are complaining about downvotes. Don't do that.
    - xorcist 12y ago
      A HSM does not need to be physically attached to "every server around the world". This is what they've built here, yet another network attached HSM, but not by following the standard PKCS protocols. (On the subject of HSM physical attacks: That's another issue altogether, and does not stop at the HSM. But normally that's not an attack you defend against, because you have the relevant contractual obligations against your infrastructure provider.) I promise not to ask about downvotes again. But the question was honest; if I'm wrong I want to know it.
      - nknighthb 12y ago
        If there's an established "correct" solution to this problem, why hasn't anyone pointed to it directly, and why didn't the banks use it? Could you point to some credible expert commentary (as opposed to anonymous noise on HN) describing why what CloudFlare has done here is wrong?
        xorcist 12y ago
        Why do you think banks don't use HSMs? They do. They are off the shelf products. If it's the "correct" solution to your problems depends on what your problem actually is. In this case Cloudflare apparently thought it was the right solution in theory but developed their own instead of using existing products and/or standards. I don't know the rationale for this, but I'd be interesting in knowing more, as you can read in my comment above. I don't know why I should point out that Cloudflare did the wrong thing. Perhaps you are confusing me with someone else? What I did say is that the alternative to the described solution is to use a HSM, and that their solution should offer equivalent security.
        nknighthb 12y ago
        You said "There is no practical improvement here.". If CloudFlare has not done something wrong, then why did you say that? Before you answer that question, remember: A hypothetical solution is not a practical solution. A practical solution is always a practical improvement over the case where there was no existing practical solution offered. And before you say "They should have used HSMs", remember: CloudFlare has made it clear that HSMs being under their control was simply not an option. It was clear in their first blog post, and just for good measure, it was made absolutely explicit in an interview with Ars[0] where CloudFlare's CEO said "there’s no vault we can ever build that they’ll trust us with their SSL keys". So, how is there no practical improvement? [0] http://arstechnica.com/information-technology/2014/09/in-depth-how-cloudflares-new-web-service-promises-security-without-the-key/ http://arstechnica.com/information-technology/2014/09/in-dep...