Current wireless technologies use a variety of methods to locally exchange and verify credentials between devices to establish trusted relationships. Scenarios in home automation networks also require this capability over the Internet, but the necessary involvement of non-expert users to setup these relationships can lead to misconfiguration or breaches of security. We outline a security system for Home Automation called Trusted Domain that can establish and maintain cryptographically secure relationships between devices connected via IP-based networks and the Internet. Trust establishment is presented in a simple and meaningful way that allows non-expert users to make the correct security decisions when enrolling new devices. We propose a social remote mutual authentication method called the PictogramDB Hash designed to easily and accurately verify certificate hash values by visualizing them with sequences of pre-defined pictograms. This method is designed to scale from smartphones and tablets down to low-resource embedded systems. The presented approach is supported by an extensive literature study, and the ease of use and feasibility of the method has been investigated via user study and implementation.