MIFARE Classic vs Ultralight: which key card chip do you need?

The four chips side by side

All four chips belong to NXP's MIFARE family, run at 13.56 MHz and follow ISO/IEC 14443 Type A, the standard for contactless cards held close to a reader. They look identical once they are sealed inside a printed card. The differences are in how much data they hold and how they protect it.

Two related chips also turn up in hotels. MIFARE Mini is a smaller-memory version of Classic used by some older systems, and MIFARE Classic 4K has four times the memory of 1K, for properties that also run cashless payments or loyalty on the card.

What the differences mean at a hotel

A room key does not need much memory. The encoder at the front desk writes the room, the stay dates and any extra areas the guest may use, and that fits comfortably on an Ultralight chip. Memory matters more when the card does several jobs at once.

• Room only, single stay: an Ultralight-family chip holds what the lock needs and is the most economical choice where your locks read it.
• Room plus lifts, spa, pool gates or parking: the sectors on a Classic 1K or 4K card, or the files on a DESFire card, let one card carry separate data for each area.
• Cashless spending or loyalty on the same card: larger-memory chips such as Classic 4K or DESFire give each application its own space.

Memory size is rarely the deciding factor, though. A lock reads the chip it was designed and configured for, and a card with a different chip will not open the door however much memory it has. That is why we confirm the chip before quoting, and why chip choice also affects what your key cards cost.

Security, in plain terms

Older chips such as MIFARE Classic have known, published weaknesses; newer chips such as Ultralight C and DESFire use stronger encryption. Which chip your locks need is set by your lock system, so ask your lock vendor before changing.

In more detail, the four chips sit at different points on the security scale:

• MIFARE Classic uses Crypto1, NXP's older proprietary cipher. NXP now offers AES-based chips, such as MIFARE Plus, as an upgrade path for Crypto1 installations.
• MIFARE Ultralight EV1 has no encryption. It relies on a 32-bit password to stop unintended changes to its memory.
• MIFARE Ultralight C adds 3DES authentication, so the card and reader prove to each other that they share a key before data is trusted.
• MIFARE DESFire EV3 uses AES with 128-bit keys, an open, widely reviewed standard, and supports several applications with separate keys.

A stronger chip only helps if the lock and encoder are set up to use its security features. Changing the chip on your cards without changing the lock configuration either does nothing or stops the cards working. Security upgrades are therefore a decision for your lock vendor and your lock settings, not for the card alone.

Hotel key cards are generally encoded with access data such as the room and the stay dates. They are not used to hold payment card details.

Which chip do your cards use?

A printed card gives no clue about the chip inside, so the quickest answer usually comes from the card itself or from your lock vendor.

1. 1

   Send us a card you use today

   Post us a working key card and we read the chip type directly. We return it if you need it.

2. 2

   Or send a photo of the lock and encoder

   The make is usually on the lock face and the model is on a label on the card encoder at the front desk. A photo of both is usually enough for us to identify the system.

3. 3

   Check with your lock vendor before any change

   If you are changing locks, updating lock software or thinking about a more secure chip, your lock vendor can confirm which chips the new setup reads.

4. 4

   Try test cards on your own doors

   We send blank test cards with the chip we propose. Encode them on your own system and try them on your doors, lifts and pool gates before anything is printed.

Our lock compatibility guide explains how chips are matched to lock systems. Once the chip is confirmed, it can go into any of our cards, from standard RFID hotel key cards and NFC and MIFARE smart cards to wooden and paper key cards. For the full hotel range, see key cards for hotels and resorts.

MIFARE, MIFARE Classic, MIFARE Ultralight, MIFARE DESFire and NTAG are trademarks of NXP B.V. Band and Key is not affiliated with NXP.