IC card serial numbers are usually 8 or 16 digits. The IC card serial number is a code that uniquely identifies the card and is used to distinguish between different cards. It is allocated by the card manufacturer for each card during the production process. An 8-bit serial number can provide 256 different combinations, while a 16-bit serial number can provide 65,536 different combinations. The length of the serial number depends on the design and requirements of the card manufacturer. Longer serial numbers can provide more combinations, thus increasing the uniqueness and security of the card.
Block access unit l Each sector has an independent set of passwords and access control l Each card has a unique serial number, which is 32 bits