Convert OpenSSH ED25519 Private Key Format to PEM format

I have generated a an ED25519 SSH key pair using

ssh-keygen -t ed25519 

The output of the id_ed25519 file is in OpenSSH format:

-----BEGIN OPENSSH PRIVATE KEY----- ... -----END OPENSSH PRIVATE KEY----- 

I would like to convert it to a PEM file format. If it were an RSA key pair, there would be no need for that as an RSA id_rsa key is already in a PEM file format but the ED25519 key pair is an OpenSSH format.

How can I convert this to a PEM file format?

2 Answers

Use

ssh-keygen -p -f path/to/your/key -m pem 

to convert your key file to PEM, but be sure to make a backup of the file first.

Taking from

I think this would work:

openssl pkey -in ed25519.pem -out ed25519.pub -pubout 

It does for a private key generated this way:

openssl genpkey -algorithm ed25519 > ed25519.pem 

I haven't tested ssh-keygen's private key format explicitly but I would assume that it is using OpenSSL under the hood. If the private key's base64 starts with "MC", then I would say it probably would be compatible.