Log in problem from Putty Client
 

My Server is highly secured. I used to access my data from SSH Putty Client. I have set public in to my server and there was private key in my PC. Unfortunately my PC is formatted and Private key is lost. How can i Solve my problem? Now I have a copy of the public key. Can i recover private through my available public key? Is there a way to keep newly generated Public key in my server?

i am fairly certain that if you loose a private key, it is gone. why not just generate a new key? also as a side note, encryption is only a small part of making a system secure. closing as many ports as possible and keeping as few processes running as possible are a couple more steps. some of the most secure linux servers are running 2.2 and 2.4 kernels.

Not quite sure what you're trying to do.

1) No you can't generate private key by knowing public key. If you could it would invalidate the whole idea of public/private key security.

2) The public key can be stored in a file called authorized_keys in the remote user's $HOME/.ssh directory. This is called establishing a trust. Once you put it there logins would no longer require a password.

I suspect you meant to ask if there was a way to save your PC's private key on the server. The answer is yes but once someone hacked into the server they would have both the public and private keys not only for the server but also the PC. You generally do not want that because they could compromise security on your PC if it were running sshd. (PuTTY does NOT provide an sshd but some folks run Cygwin with sshd to allow ssh to their Windoze PCs.) It is better to generate a new private/public key and re-establish the trust by updating server's authorized_keys (assuming you want a trust rather than using a password).