While you create normal RSA keys with
ssh-keygenyou find yourself with a personal key in PEM format, and a public key in OpenSSH format. Each have been described intimately in my submit Public key cryptography: RSA keys. In 2014, OpenSSH launched a customized format for personal keys that’s apparently much like PEM however is internally fully totally different. This format is utilized by default whenever you create ed25519 keys and it’s anticipated to be the default format for all keys sooner or later, so it’s price taking a look.
An in-depth evaluation of what’s contained in the OpenSSH personal key format and the way it’s totally different from the usual PEM format.