TODO

-   Add the rest of OpenSSH's extensions
    from http://api.libssh.org/rfc/PROTOCOL:
    -   Additional public key algorithms:
        -   "ssh-rsa-cert-v00@openssh.com"
        -   "ssh-dsa-cert-v00@openssh.com",
        -   "ecdsa-sha2-nistp256-cert-v01@openssh.com",
        -   "ecdsa-sha2-nistp384-cert-v01@openssh.com" and
        -   "ecdsa-sha2-nistp521-cert-v01@openssh.com"
    -   Certificate keys
        http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.certkeys?rev=HEAD
    -   Channel write close extension "eow@openssh.com"
    -   "no-more-sessions@openssh.com" extension to disallow additional sessions

-   Take a closer look at
    http://books.google.fr/books?id=9FSaScltd-kC&printsec=frontcover&
        hl=fr&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false
    The book lists several aliases / additional algorithms used by
    various implementations of the secure shell.

-   Suite B crypto suites:
    -   http://www.rfc-editor.org/rfc/rfc6239.txt

-   P6R's public key subsystem:
    -   http://www.rfc-editor.org/rfc/rfc7076.txt

-   Other useful resources:
    -   https://www.iana.org/assignments/ssh-parameters/ssh-parameters.xhtml