Sorry for nagging about the SSH / Public Key topic.

Some follow-up on episode 415. The reason why you couldn’t directly import a PuTTY generated key file into the server OpenSSH environment is because a .ppk file contains BOTH the public and private key. (The “.ppk” extension probably stands for something like: public private key). When you copy the public key part into an “authorized_keys” file on the linux server you should be able to authenticate with the PuTTY generated key. BTW: This is also suggested in the “Key” field of “PuTTY Key Generator”

E.g. see: http://www.ualberta.ca/CNS/RESEARCH/LinuxClusters/pka-putty.html

The way you made your solution working is unsafe because you now have multiple copies of your server’s private key. And here is why:
What you did was copying the private key (In your case “id_rsa”) form the linux server to your XP machine and imported it into PuTTY. (You normally don’t want to do that! Remember your Fort Knox remark about the private key.) So you actually “stole” the private key from your linux server, re-generated the public key with PuTTY and stored the key pair in a .ppk file. The only reason why this worked is that you knew the passphrase of the server’s private key. (Normally Hackers work this way).

When Darren asked you to open the .ppk file in Notepad++ you could clearly see the linux server’s public AND private key… (This is not probably what you want). When finally connecting to the ssh server you used your local copy of the server’s private key.

The normal way to setup these kind of connections is demonstrated in the hyperlink mentioned above. So, the PuTTY generated public key should be copied to the linux server and added to a “authorized_keys” file, not by copying the servers private key to the XP system.

Regards, Jan Hendrikx.
(Located: The Netherlands)

When I watched episode 415, I noticed something in your explanation that, if I’m correct, is wrong. It’s something in your story about SSH and public key encryption.

Quote 1:”…and you use the public key to encrypt your, you know, to encrypt and along with your passphrase…” (AVI file: 0h:11m:19s)

Quote 2:”…everyone can encrypt a message or, within variuos implementations, encrypt it with the passphrase..” (AVI file: 0h:12m:13s)

This suggests that if someone wants to send you an encrypted message/file, he or she needs your public key ALONG with the passphrase you entered during the creation of your key pair. This isn’t right in my opinion.
The only reason for the passphrase to exist is to protect your private key from abuse in case someone steels it.

(Also see: http://my.safaribooksonline.com/9780596101954/using_passphrase_protection_of_ssh_keys?portal=informit).

That is why, each time you want to use your private key, your ssh-agent program will prompt you for the passphrase.

Cheers, Jan Hendrikx.
(Location: The Netherlands)

We can definitely do alternatives to what I did in my segment. I actually have already gotten feedback regarding that and plan to do something with pamusb soon!