[hibikir]

Key management is a major issue across the board, not just web servers. Even a theoretically unbreakable crypto will always have a weakness if the keys themselves are compromised. Stopping keys from being copied is a major challenge though, because anything you can do to truly protect them involves major hassle.

Think of the problems credit card processors deal with: Hiding the keys themselves from their own employees, so that getting a root password is not enough to be able to just take all the credit card information. You don't want the key in any filesystem, and you don't want the key in an easy to retrieve memory location. You end up with servers that require multiple people to boot up, as the keys only really appear when multiple people provide their own piece of the secret.

Eventually, enough security leads to the risk of data loss, as an error can make the keys become unrecoverable.

This is why we have to add security breach detection, and make recovering from a breach easy and having low consequences. Linus said that with enough eyeballs, all buts are shallow. With enough attackers, all systems are insecure.

[remosi]

If I was running a bank, I'd hopefully use a proper HSM. You ask it to generate a private key, you then ask it for the public key, get it signed into a cert, and use that. The HSM promises to never give out the private key to anyone (including the administrator), usually in a tamper evident way (if someone did manage to extract the key, you'd notice). Even if you have root on a machine that has an HSM plugged into it, you can't get the private keys out.

However, my personal webserver isn't a bank. Not everyone can justify spending this much money on a HSM to get this level of assurance. What I'm proposing is a simpler solution that isn't robust against sophisticated attacks (eg when the attacker manages to get root), but is far more robust to some classes of the common attacks we see today (where the attacker can read any memory/file that the webserver has permissions to see).

[mhb]

For other curious readers:

HSM = Hardware Security Module (http://en.wikipedia.org/wiki/Hardware_security_module)