It is done by using the same ssh messages for v4 and v5 authentication
(since the ssh.com does not now anything about v4) and looking at the
contents after unpacking it to see if it is v4 or v5.
Based on code from Björn Grönvall <bg@sics.se>
PR: misc/20504
new features description elided in favor of checking out their
website.
Important new FreeBSD-version stuff: PAM support has been worked
in, partially from the "Unix" OpenSSH version, and a lot due to the
work of Eivind Eklend, too.
This requires at least the following in pam.conf:
sshd auth sufficient pam_skey.so
sshd auth required pam_unix.so try_first_pass
sshd session required pam_permit.so
Parts by: Eivind Eklend <eivind@FreeBSD.org>