Information / Note

An interesting or easy-to-miss fact that won't get you into much trouble if you miss it.

Light Warning

A light warning, that could make life a little harder if you miss it.

Stern Warning

An important warning, that could get you into trouble if you miss it.

FM

Family Code

The Family Code usually at the start of the code between brackets and consists of a number from 0 through 255 | (01)

This code identifies the application according to ISO norms. Sometimes used in combination with the Site Code / Facility Code.

AC

Agency Code

The term Agency Code is synonymous to (means exactly the same as) Family Code?

AID

Application Identifier

The term identifies an application (and certain kinds of files in card file systems) in a smart card or Java Card in accordance with ISO/IEC 7816-5. An AID consists of two data elements: a registered identifier (RID) and a proprietary identifier (PIX).

ATQA

Answer To reQuest, Type A

Answer To reQuest code A is a two-byte code in Near Field Communication (NFC) technology that is used to identify the type of RFID tag or device that is communicating with the NFC reader. When an NFC reader sends out a signal to communicate with a nearby tag or device, the tag or device responds with its ATQA code to indicate its presence and capabilities.

The ATQA code contains information about the type of tag or device, such as its manufacturer, memory capacity, and communication protocol. It helps the NFC reader to determine how to communicate with the tag or device and what type of data can be exchanged between them. The ATQA code is the first piece of information that is exchanged during the NFC communication process and is used to establish a connection between the reader and the tag or device. See REQA and SAK definitions for more info.

FC

Facility Code

Facility Codes are sometimes called a Site Code or a Batch Code.

A project code intended to be equal for a batch of cards. Ideally equal for the whole population of a project. They are an extra level of security often used in the coding of proximity cards. The code is usually two hex characters making a value range of 0-255. Usually located after the Family Code. It is used to group card by a number that identifies that group.

SC

Site Code

The term Site Code is synonymous to (means exactly the same as) Facility Code.

BC

Batch Code

The term Batch Code is synonymous to (means exactly the same as) Facility Code.

CC

Client Code

Country Code

Customer Code

The terms Client Code, Country Code or Customer Code are synonymous to (meaning exactly the same as) Facility Code.

UID

Unique IDentifier

User IDentifier

A unique ID used to identify the card.

It is usually 4 bytes long containing the value range 0-15, but can also be 7 bytes (double size UID) value range 0-127 or 10 Bytes (triple size UID) value range 0-1023.

CSN

Card Serial Number        

The term Card Serial Number is synonymous to (means exactly the same as) UID.

UUID

Universally Unique IDentifier

The term Card Serial Number is like a UID, but has a greater focus on it's uniqueness.

FASC-N

Federal Agency Smart Credential - Number

This term is also a kind of UID. But it has a specific definition.

It is one of the primary identifiers on the PIV Card for physical access control, as required by FIPS 201 (FIPS = Federal Information Processing Standard (USA)). The FASC-N is a fixed length (25 byte) data object that is specified in [NIST SP 800-73-4] (NIST = National Institute of Standards and Technology (USA)) and included in several data objects on a PIV Card. (see: FASC-N NIST 201-3)

CRC

Cyclic Redundancy Check

A cyclic redundancy check is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to digital data.Blocks of data entering these systems get a short check value attached, based on the remainder of a polynomial division of their contents. On retrieval, the calculation is repeated and, in the event the check values do not match, corrective action can be taken against data corruption. CRCs can be used for error correction.

CRCs are so called because the check (data verification) value is a redundancy (it expands the message without adding information) and the algorithm is based on cyclic codes. CRCs are popular because they are simple to implement in binary hardware, easy to analyze mathematically, and particularly good at detecting common errors caused by noise in transmission channels. Because the check value has a fixed length, the function that generates it is occasionally used as a hash function.

Parity Bit

A parity bit, or check bit, is a bit added to a string of binary code. Parity bits are a simple form of error detecting code. Parity bits are generally applied to the smallest units of a communication protocol, typically 8-bit octets (bytes), although they can also be applied separately to an entire message string of bits.

The parity bit ensures that the total number of 1-bits in the string is even or odd. Accordingly, there are two variants of parity bits: even parity bit and odd parity bit. In the case of even parity, for a given set of bits, the bits whose value is 1 are counted. If that count is odd, the parity bit value is set to 1, making the total count of occurrences of 1s in the whole set (including the parity bit) an even number. If the count of 1s in a given set of bits is already even, the parity bit's value is 0. In the case of odd parity, the coding is reversed. For a given set of bits, if the count of bits with a value of 1 is even, the parity bit value is set to 1 making the total count of 1s in the whole set (including the parity bit) an odd number. If the count of bits with a value of 1 is odd, the count is already odd so the parity bit's value is 0. Even parity is a special case of a cyclic redundancy check (CRC), where the 1-bit CRC is generated by the polynomial x+1.

SAK

Select Acknowledge, Type A

PICC

Proximity Integrated Circuit Card (a “Contactless Card”)

Endianness        

Endianness is the order in which bytes within a word of digital data are transmitted over a data communication medium or addressed (by rising addresses) in computer memory, counting only byte significance compared to earliness. Endianness is primarily expressed as big-endian (BE) or little-endian (LE), the terms were introduced in 1980. The adjective endian (mimicing the word Indian) has its origin in the writings of 18th century Anglo-Irish writer Jonathan Swift. In the 1726 novel Gulliver's Travels, he portrays the conflict between sects of Lilliputians, a small gnome-like people called Big-Endians and Little-Endians (the sects feuded over breaking the shell of a boiled egg from the big end or from the little end. By analogy, a CPU may read a digital word big end first, or little end first, and there is no general agreement on which is better. Big-endian (BE) is reading from left to right. Other orders then BE or LE might be called middle-endian or mixed-endian (ME).

Decimal

Base 10 numeric system ( 1011 in a decimal system = (going from the right-most digit to the left) 1 * + 1 * + 0 * + 1 * => 1 * 1 + 1 * 10 + 0 * 100 + 1 * 1000 => 1011)

Bit

A bit is the smallest unit in a Binary numeric system, it is either a 0 or a 1. A Byte consist of 8 bits.

Nibble

A nibble is four bits. 1 Byte = 2 nibbles = 8 bits

Binary

Base 2 numeric system ( 1011 in a binary system = (going from the right-most digit to the left) => 1 * + 1 * + 0 * + 1 * => 1 * 1 + 1 * 2 + 0 * 4 + 1 * 8 => 11)

Binary LE

Binary Little Endian, a word with these digits 1-0-1-1 would be written and read in the 'reverse' order 1-1-0-1.

Binary BE

Binary Big Endian, a word with these digits 1-0-1-1 would be written and read in that same order 1-0-1-1.

Hexadecimal

Base 16 numeric system ( 1011 in a hexadecimal system = (going from the right-most digit to the left) => 1 * + 1 * + 0 * + 1 * => 1 * 1 + 1 * 16 + 0 * 256 + 1 * 4096 => 4113).

ASCII

American Standard Code for Information Interchange

Originally based on the (modern) English alphabet, ASCII encodes 128 specified characters into seven-bit integers.

Hex ASCII converts the ASCII code bits into Hexadecimal Bytes. ASCII Decimal -> Binary converts a readable ASCII value to it's binary value.

HID / HID®

Human Interface Device / Hughes Identification Devices®

Normally this term is meant to mean Human Interface Device, a type of computer device usually used by humans that takes input from or provides output to humans.

However we do use the other meaning of HID, the card technology and company Hughes Identification Devices (HID®). When we use HID in this meaning we will add a registered trademark symbol at the end of the acronym to make this clear.

Reader Mode HID

Keyboard emulation. The reader functions as if it is a keyboard sending the information as keystrokes.

Reader Mode HID RAW

This is the only mode in which card analysis is possible. The information is send as a binary stream to communicate with the Spider RFID Reader Tool.

PACS

Physical Access Control System

Refers to an access control system with physical components.

PICC

Proximity Integrated Circuit Card

REQA

REQuest Anti-Colission command in ISO14443A.

Gain and Filter

The gain and filter setting for Low Frequency (LF) card technologies can be a difficult setting to understand.

Gain is a measure of the ability of a two-port circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output port by adding energy converted from some power supply to the signal.

A cutoff frequency, corner frequency, or break frequency is a boundary in a system's frequency response at which energy flowing through the system begins to be reduced (attenuated or reflected) rather than passing through. Typically in electronic systems such as filters and communication channels, cut-off frequency applies to an edge in (in our case) a Low Pass (LF Filter) or High Pass (HF Filter) characteristic.

Look up the result you need in the table below. The gain is calculated by multiplying Gain 0 and Gain 1. If we take the value '64' as an example we would get 16 * 6.22 = 99.52 (this is about 40dB gain ((Log(10) * 99.52 )*20 ), furthermore this value has a High Pass Filter (High Frequency Corner) of 40 Hz and a Low Pass Filter (Low Frequency Corner) of 3 kHz.

Lookup table for dB:

BCD

Binary Coded Decimal

Binary-Coded Decimal (BCD) is a class of binary encoding of decimal numbers where each digit is represented by a fixed number of bits, usually four or eight. Sometimes, special bit patterns are used for a sign or other indications (e.g. error or overflow).

In byte-oriented systems (i.e. most modern computers), the term unpacked BCD usually implies a full byte for each digit (often including a sign), whereas packed BCD typically encodes two digits within a single byte by taking advantage of the fact that four bits are enough to represent the range 0 to 9. The precise four-bit encoding, however, may vary. Unpacked BCD has a range of 0-9 per Byte (using a length of 1 Byte = 2 nibbles = 8 bits) and Packed BCD has a range of 0-99 per Byte (using a length of 1 Byte = 2 nibbles = 8 bits). A binary number of 1 Byte has a range of 0-255.

Packed BCD measured in nibbles

Packed BCD measured in nibbles is Packed BCD. Normally Packed BCD is measured in bytes (a string of 8 bits) divided into two nibbles. In some cases you might need an odd number of nibbles, which would result in a fractured Byte (like 3.5 Bytes), this is not done, nibbles should be used in such cases. Use the Packed BCD measures in nibbles if it is possible that you might need an odd number of nibbles. Obviously a BCD with a possible odd number of nibbles has to be Packed BCD. In the table below a number of examples are given with a few of the different types of BCD.