The invention provides an authentication unit for reading identification and/or authentication information from a tag or object. The authentication unit includes a near-field reader configured to read a first identification feature based on inherent disorder, and a far-field reader configured to read a second identification feature, such as a bar code, optical characters, or an RFID tag. The near-field and far-field readers may be combined in a single integrated scanning module, which also includes circuitry for receiving signals from the readers, and an interface for communicating with a host device.