Security
A critical aspect of any network application these days is security.
Stem hubs communicate with each other via standard internet sockets.
This communication can be made secure by tunneling over existing
open source products such as SSH and Stunnel. Stem runs the security
program and has it connect with the remote hub and its stdin/stdout
is used for the local connection. The Stem::Proc cell is used to
manage this external security program and it provides all the I/O
support needed. The Stem::Portal cell is used to connect Stem hubs
together and it has configuration options to select the desired
security application and options. A Stem hub can listen for portal
connections using a Listen socket bound to localhost or an IP
address. By using localhost and a secure transport, a Stem hub
cannot be accessed by any unauthorized programs.