Openssh Private Key to RSA Private Key
(I am using MAC)
My id_rsa starts with
-----BEGIN OPENSSH PRIVATE KEY-----
but I expect it to starts with
-----BEGIN RSA PRIVATE KEY-----
I have send my id_rsa.pub to server administrator to get the access to server, so I don't want to generate a new key.
Is there any way that I can transfer my id_rsa which is a openssh private key to a RSA private key? (command please.)
If I can transfer, do I also need to transfer id_rsa.pub? (command please.) It seems id_rsa.pub doesn't have a header like id_rsa, so I am not sure if I should also transfer this.
Thank you!
You have an OpenSSH format key and want a PEM format key. It is not intuitive to me, but the suggested way to convert is by changing the password for the key and writing it in a different format at the same time.
The command looks like this:
ssh-keygen -p -N "" -m pem -f /path/to/key
It will change the file in place, so make a backup of your current key just in case. -N "" will set the passphrase as none. I haven't tested this with a passphrase.
The public key should be fine as is.
For full explanation of the above command, see the -m option here: https://man.openbsd.org/ssh-keygen#m
Here's what worked for me for an in-place conversion of a key with a passphrase:
ssh-keygen -p -P "old passphrase" -N "new passphrase" -m pem -f path/to/key
You can achieve this easily if you can get your hands on a linux system. I am using ubuntu 18.04 and did the following:
- update packages:
sudo apt update - install putty:
sudo apt install putty - install puttygen:
sudo apt install putty-tools - convert the private key to the intermediate format SSHv2:
puttygen yourkey -O private-sshcom -o newkey - convert it back to RSA/PEM:
ssh-keygen -i -f newkey > newkey_in_right_format
And you are good to go