MIFARE Classic is commonly used for access control systems that don’t require a high security solution, such as corporate office buildings or gym and leisure facilities. The memory inside a MIFARE Classic chip is essentially just a storage device divided into sections and blocks for different parts of the data.
Information is encrypted on a MIFARE Classic chip using a 48-bit key. Following security concerns and successful attempts to attack and reverse-engineer MIFARE Classic cards, the series has evolved to improve its security. However, NXP is now recommending that organisations using MIFARE Classic-based systems migrate to higher security products in order to guarantee protection from attacks.
MIFARE Plus was designed to replace MIFARE Classic while remaining backwards-compatible. Equipped with AES128 encryption, MIFARE Plus offers a higher level of security when combined with AES-backed readers. The main benefit of MIFARE Plus was that MIFARE Classic systems could be upgraded to a higher level of security seamlessly, with no additional infrastructure required.
MIFARE Ultralight is designed to be inexpensive and generally single-use, as they are not equipped with cryptographic security features. They have only 512 bits of memory and are often used for disposable ticketing for large events such as concerts or sports games.