master 
develop
#Introduction
pk is a way to expose services behind a layer that employs a shared-secret port-knocking protocol to control client access.
When a client successfully authenticates, the daemon responds with the port on which the hidden service is listening, and installs an iptables rule to permit the client to connect to the hidden service.
##Server
from pk import server
secret_port = 8080
secret = "very-secret"
# setup portknocker daemon
daemon = server.PkDaemon()
daemon.register(secret_port, secret)
daemon.start()##Client
from pk import client
secret = "very-secret"
pkclient = client.PkClient(host, secret)
# Get a socket connection to the hidden service
hidden_conn = pkclient.connect()##TODO Cool enhancements:
- Support for multiple hidden services
- Support for closing firewall to clients who don't heartbeat to the daemon