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 passphrase only once, when my system boots.

How do I emulate 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 could seamlesly connect in the same manner in both Winodws and Linux.

Can anyone help ?

Answer 1

It's probably easier to create your keys under linux and use PuTTYgen to convert the keys to PuTTY format.

PuTTY Faq: A.2.2

Answer 2

puttygen supports exporting to an OpenSSH compatible format.

1. Open PuttyGen
2. Click Load
3. Load your private key
4. Go to Conversions->Export OpenSSH and export your private key
5. Copy your private key to ~/.ssh/id_dsa (or id_rsa).

6. Create the RFC 4716 version of the public key using ssh-keygen

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

7. 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

See this and this for more information.