convert F-Secure/Tectia SSH format to OpenSSH format?

Solutions:
To convert F-Secure public key to OpenSSH format
# ssh-keygen -i -f path/to/public.key >> path/to/new/opensshpublic.key

To convert F-Secure private key to OpenSSH format
# ssh-keygen -i -f path/to/private.key > path/to/new/opensshprivate.key

To convert OpenSSH public/private key to another commercial key.
Public key conversion:
# ssh-keygen -e -f path/to/opensshpublic.key > path/to/publickey.key

Private key conversion:
# ssh-keygen -e -f path/to/opensshprivate.key > path/to/privatekey.key