MiFare Classic

MiFare (ISO 14443A) is a contactless RFID chip card technology. The cards are divided into different memory sizes.

Each block consists of 16 bytes. The last block of a sector (sector trailer) contains two authentication keys to protect the sectors from unauthorized access. The sector trailers must not be overwritten, as the associated sectors may be rendered unusable. Sectors 0 and 16 also play a special role. These sectors manage memory that is important for multi-applications. Sector 0 also stores vendor data, including the UID.