Abstract: A method for digitally watermarking an image or video by replacing the least significant bit of each pixel of the image with data so that an image or video can be authenticated by removing the least significant bits, reassembling the bits into a data stream and decoding the data stream.

Abstract: The present invention provides a portable handheld security device. The security device comprises a central processing unit in communication with a memory storage device, a video display screen, at least one camera, a transmitting device, a receiving device, an input device, and a power supply. The security device further comprises a device for generating ultra wide band ground penetrating radar and/or millimeter wave radar for identifying objects of interest in closed containers. In addition, the transmitting device and the receiving device are ideally capable of selecting between available communication network signals, determining which network signal is the best signal at a given time, and automatically switching between the available signals to maintain optimum reception and transmission quality.