I'd like to announce the Secure ROS project (http://secure-ros.csl.sri.com/). Secure ROS is a "fork" of core ROS packages to enable secure communication among ROS nodes. The main goal of Secure ROS is to enable secure communication for regular users of ROS.
Secure ROS uses IPSec in transport mode and modified versions of the ROS master, _rospy_ module and _roscpp_ library to ensure secure communication. At run time, the user can specify authorized subscribers and publishers to topics, setters and getters to parameters and providers (servers) and requesters (clients) of services in the form of a YAML configuration file for the ROS master. Secure ROS allows only authorized nodes to connect to topics, services and parameters listed in the configuration file.
The goal of Secure ROS is similar to SROS which was announced last year, but the approach is different. Secure ROS allows easy re-use of existing ROS nodes and packages.