What is the ext. or mime-type of open-ssh-certs? (Puttygen)

i usualy use puttygen(windoz) to generate ppk-files and open-ssh-certificates (i write an ajax-web-putty using "Java Server Faces").

In putty-gen-menu i select "Conversions->Export OpenSSH Key" but no default-extesion is given!

Is even there an specific ext/mime-t开发者_JS百科ype?

Regards