SavaPage supports Radio Frequency Identification (RFID) as authentication method.
RFID is the technology for uniquely identifying items using radio waves. A basic RFID system comprises a passive tag, a reader, and an antenna, where the reader sends an interrogating signal to the tag via the antenna, and the tag responds with its Unique Identification (UID).
In this way RFID tags are commonly used as authentication token: the RFID reader connected to the authenticator just passes the UID (Card Number) of the tag. Applications are abundant, ranging from tags embedded into retail products to help stores keep tabs on inventory, to tags embedded into animals to keep track of life stock. RFID is also applied in passports and credit cards, as well as identification badges that let employees access secure areas.
Near Field Communication (NFC) is a more recent, finely honed version of RFID with a much broader application. While RFID is a one-way communication system only, with data flowing from tag to reader, NFC can also be set up for two-way communication. However, NFC operates at a maximum range of about 4 inches (10 centimeters) and uses High Frequency ( HF) RFID readers at 13.56 MHz.
Since SavaPage is targeted at the same HF RFID readers and tags, albeit in one-way communication, this manual uses the more common terms NFC Card and NFC Reader for the tag and reader role. In some contexts the terms Card and Card Reader will be used as shorthand.
SavaPage supports two Card Reader types.
A Local Card Reader: a keyboard emulating device that “types” the UID (Card Number) each time a Card is swiped.
A Network Card Reader: a software component, implemented on a dedicated device (like a Raspberry Pi®), that interacts with an NFC Reader after a card swipe and sends the UID to the central SavaPage server.
SavaPage stores the Card Number (UID) in lower case HEX format, with Least Significant Byte (LSB) first. So, at the interfaces where the UID is captured, the output format and byte order must be specified as HEX or DECIMAL and LSB or MSB (Least or Most Significant Byte) first. This information is used by SavaPage to convert the captured Card Number to its internal HEX/LSB standard.
 RFID tags are either Active or Passive. Active tags have their own power supply by which they can broadcast with a read range of up to 100 meters. Passive tags do not have their own power source. Instead, they are powered by the electromagnetic energy transmitted from the RFID reader. Because the radio waves must be strong enough to power the tags, passive RFID tags have a read range from near contact to a few meters.