Seems simple but there are many types of contactless cards (RFID 125 kHz, Motorola/Indala W26, Motorola/Indala W27, Motorola/Indala ABA Track II, Motorola/Indala Lite, Motorola/Indala , KANTECH, HID Prox, Proxlite, MIFARE, MIFARE + RFID 125 kHz, LEGIC Advant, TIRIS 134 kHz, COTAG, MULTI ISO, PAC, HID UDF, HID iClass, HiTAG, HiTAG2 etc.). With contactless cards, readers would normally read the unique serial number embedded on the card.

This can get fairly complicated so we will start at the beginning. Let’s take for example a Classic MIFARE 1k card as these are encountered in many PaperCut sites.

A MIFARE Classic 1K card has 1024 bytes of storage, split into 16 <em>sectors</em>. Each sector is protected by two different keys, called <em>A</em> and <em>B</em> (more on this later). 16 bytes per sector are reserved for the keys and access conditions and cannot normally be used for user data. Also, the very first 16 bytes contain the serial number of the card and certain other manufacturer data, are read-only and live in sector zero.

This brings the total storage capacity of these cards down to 752 bytes for a Classic 1k MIFARE card. None of this is really relevant but we thought it may be interesting for some people. When a Mifare card is first created in the factory it has its first sector, sector zero, programmed with a unique serial number. This is set by the factory into read-only memory – so this number cannot be changed and stays with the card.

With a MIFARE reader attached to a copier, the reader simply reads the unique ID. PaperCut will lookup that number against its database of users and log on the correct user. If no user is found, PaperCut will prompt you to assign the card to a user account and ask for your network username and password.
This self-registration service takes away all the administration of card numbers by staff members. Before self-registration, a site needed to know the serial numbers for each card and batch import them into PaperCut. Now this isn’t always too much of a problem but many sites don't actually know the serial number of cards and often the card supplier does not have a record either, so the process often involved an IT staff member with a card reader and a lot of copy and pasting.

Thankfully self-registration works really well. It’s especially handy if users lose a card as they can just be issued with a new card and that’s all the admin it takes. Please note that self-registration is only available on supported devices.

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