The contactless smart cards require close proximity to a reader to achieve data transmission. Both the smart card and reader have internal antennas and wireless circuitry for secure communication. Using advanced data encryption techniques, contactless smart card are highly applied for access control, vending and cafeteria payment.
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. Each key can be programmed to allow operations such as 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 MIFARE Classic® 1K, 3440 bytes for MIFARE Classic® 4K, and 224 bytes for Mini. It uses an NXP proprietary security protocol (Crypto-1) for authentication and ciphering.