fwknop implements an authorization scheme known as Single Packet
Authorization (SPA) for Linux systems running iptables.
This optionally uses gpg and libgpgme if they are available. Using
gpg with fwknop is highly recommended.
Maintained by: Eric B. Pratt
Approved by: Niels Horn
Keywords: port knocking,SPA,security,iptables
(the SlackBuild does not include the source)