gpg: failed to create temporary file '/var/lib/lurker/.#lk0x56a81100.hantslug.org.uk.20335': Permission denied
gpg: keyblock resource '/var/lib/lurker/pubring.gpg': Permission denied
gpg: Signature made Mon Mar 8 22:30:37 2010 GMT
gpg: using DSA key 2099B64CBF15490B
gpg: Can't check signature: No public key
Hi Leo,
On Mon, Mar 08, 2010 at 10:14:43PM +0000, Leo wrote:
> My understanding was that a client could have a private key. Its public
> key could then be put on the server it wanted to ssh into. I thought the
> passphrase was to encrypt the private key on the client machine and so
> prevent it being discovered if the machine was e.g. stolen. My thinking
> was therefore that if the disk on which the private key is saved was
> encrypted, the private key would still be reasonably secure even if it
> wasn't protected by a passphrase. Is my understanding flawed/completely
> wrong?
You're right that a passphrase on an ssh private key protects the
key if someone gets hold of the file, but it would not be safe to
say that encrypting your disk prevents people from getting hold of
your files.
However, a bug or exploit in the software that you're running could
lead to remote compromise of your machine while it's running and
while apps have access to its files. That would then give the
attacker access to everywhere that your (passphrase-less) SSH key
has access. Similarly if someone got access to your computer while
it was still running. A rather more likely risk is simply human
error - you or another administrator exposing your own private key
file by accident.
(note also that root on a machine can read the ssh-agent secrets of
any user on that machine, so people with passphrased ssh keys do
still expose themselves when running ssh-agent and especially when
forwarding it to remote hosts that may not be as well secured)
Cheers,
Andy
--
http://bitfolk.com/ -- No-nonsense VPS hosting
