MIFARE is the NXP Semiconductors-owned trademark (a spin-off company formed out of Philips Semiconductors) of the reputedly most widely installed contactless smartcard, or proximity card, technology in the world with 500 million smart card chips and 5 million reader modules sold. The patented technology is owned by NXP Semiconductors, with its Headquarters in Eindhoven, the Netherlands and main business sites in Nijmegen, the Netherlands and Hamburg, Germany.

The MIFARE proprietary technology is based upon the ISO/IEC 14443 (RFID) Type A 13.56 MHz contactless smart card standard.

The technology is embodied in both cards and readers (also referred to as a Proximity Coupling Device).

The MIFARE name covers four different kinds of contactless cards :

MIFARE Classic (Standard): employ a proprietary high-level protocol instead of ISO/IEC 14443-4, with an NXP proprietary security protocol for authentication and ciphering.

MIFARE UltraLight: employ the same protocol as MIFARE Classic, but without the security part and slightly different commands

MIFARE DESfire: are smartcards that comply to ISO/IEC 14443-4 with a mask-ROM operating system from NXP.

MIFARE ProX, SmartMX: are NXP Semiconductors brand names for smartcards that comply to ISO/IEC 14443-4.

MIFARE Classic (Standard)

The MIFARE Classic card is fundamentally just a memory storage device, where the memory is divided into segments and blocks with simple security mechanisms for access control. They are ASIC based and have limited computational power. Thanks to their reliability and low cost, those cards are widely used for electronic wallet, access control, corporate ID cards, transportation or stadium ticketing.

The MIFARE Classic 1k offers 1024 bytes of data storage, split into 16 sectors; each sector is protected by two different keys, called A and B. They can be programmed for operations like reading, writing, increasing value blocks, etc.). MIFARE Classic 4k offers 4096 bytes split into forty sectors, of which 32 are same size as in the 1K with eight more that are quadruple size sectors. MIFARE Classic mini offers 320 bytes split into five sectors. For each of these card types, 16 bytes per sector are reserved for the keys and access conditions and can not normally be used for user data. Also, the very first 16 bytes contain the serial number of the card and certain other manufacturer data and are read only. That brings the net storage capacity of these cards down to 752 bytes for Classic 1k, 3440 bytes for Classic 4k, and 224 bytes for Mini.

The simplicity of the basic cards means that they are inexpensive, which is largely the reason for their success in large-scale deployments, such as Oyster card.