A portable security device for a computing system includes a housing, an interface at least partially disposed within the housing, a trusted platform module within the housing that is coupled to the interface, and a controller within the housing that is coupled to the trusted platform module and the interface. The interface is configured to engage a plurality of different devices and provide communication between the portable security device and an individual device when engaged with the individual device. In some examples, the trusted platform module can receive power from the individual device via the interface when the portable security device is engaged with the individual device. The controller includes logic to detect when the portable security device is coupled to the individual device via the interface.