Jenkins: what is the correct format for private key in Credentials

Question

I\'m creating a job in Jenkins 2.152 running on Windows Server 2016 which needs to pull from a git repo hosted on bitbucket.org. I tested the ssh key through git-bash so I k

Answer 1

So just to add an answer to actually convert a key from the new OPENSSH format to the older PEM format:

$ ssh-keygen -f blah.key
Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in blah.key.
Your public key has been saved in blah.key.pub.
The key fingerprint is:
SHA256:ndMFvZjbD7M3MoqFy8+me74gPhcuoDVLF2/Oh+hXQ8I perbelding@erpelbook4.local
$ head -n 1 blah.key
-----BEGIN OPENSSH PRIVATE KEY-----
$ ssh-keygen  -f blah.key -m PEM -p
Key has comment 'redacted'
Enter new passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved with the new passphrase.
$ head -n 1 blah.key
-----BEGIN RSA PRIVATE KEY-----

ssh-keygen -p changes the passphrase but it does not mind the new passphrase being the same (even none) as the old one and in the process can convert the format.