How to convert SSH keypairs generated using PuTTYgen (Windows) into key-pairs used by ssh-agent and Keychain (Linux)

Question

I've generated key pairs using PuTTYgen and been logging in using Pageant so that I have to enter my pass-phrase only once when my system boots.

How do I achieve this in Linux? I've heard of keychain but I hear that it uses a different key pair format - I don't want to change my Windows keys and it would be nice if I could seamlessly connect in the same manner in both Windows and Linux.

Answer 1

With the help of puttygen you can export your private key to an OpenSSH compatible format. Then you can use OpenSSH tools to recreate the public key.

Open your PuttyGen

Click on Load

Load your private key

Now you go to Conversions-> Export OpenSSH and export your private key

Copy your private key to ~/.ssh/id_dsa (or id_rsa).

Then create the RFC 4716 version of the public key using ssh-keygen

ssh-keygen -e -f ~/.ssh/id_dsa > ~/.ssh/id_dsa_com.pub

Now convert the RFC 4716 version of the public key to the OpenSSH format:

ssh-keygen -i -f ~/.ssh/id_dsa_com.pub > ~/.ssh/id_dsa.pub