Convert pem key to ssh-rsa format

Question

I have a certificate in der format, from it with this command I generate a public key:

openssl x509 -inform der -in ejbcacert.cer -noout -pubkey         


        

Answer 1

ssh-keygen -i -m PKCS8 -f public-key.pem

Answer 2

ssh-keygen -f private.pem -y > public.pub