Digital spectacles use cloud computing and have a small camera that captures 400 facial images per second, sending them to a central database of over 13 million faces. It can compare biometric data from a face to known criminals' data and immediately alert authorities of any matches. The spectacles use Lumus LOE technology, which projects video images into the lenses using total internal reflection so that video appears floating in the field of vision. Security of data in the cloud is important, so technologies like Nessus use strong encryption when transferring data between locations.