Understanding
the memory structure of MIFARE 1k and 4k Classic Smartcards
This article shows the memory structure which is used in MIFARE
1k and 4k smartcards
Basically the MIFARE Classic card is a memory storage device.
The memory is divided into sectors,
which are also divided into blocks of 16
bytes.
MIFARE
Classic 1K card
The MIFARE Classic 1K
card has 16 sectors, each of which are divided
into four blocks. If we do the math, we can figure out how the memory
structure would be like: 16 bytes (1 block)
* 4 blocks * 16 sectors = 1024 bytes.
MIFARE 1K card memory structure
The above image
shows the memory structure of MIFARE 1K card. From this we can clearly
understand different blocks which are used for various purpose .
Here, the Block’s
shows where we can write data in to the card. you have plenty of location in a
card that you can write data. Also there are some restricted blocks you should not write in to.
Restricted blocks
Here the restricted blocks CSN,CIS,Site Key block’s. We cant write data in
these blocks.
MIFARE
Classic 4K card
The MIFARE Classic 4K card has 40 sectors, 32 of which are
divided into four blocks and the remaining 8 are divided into 16 blocks. 16 bytes (1 block) * 4 blocks * 32 sectors
+ 16 bytes (1 block) * 16 blocks * 8 sectors = 4096 bytes. The memory
structure is as follows:
MIFARE 4K card memory structure
The number on the blocks
indicates its index. Each sector is protected by the site key written in the
last block of the sector. For example, block 3 contains the site key for sector
1 and block 7 for sector 2. The last block in each sector also contains access
conditions information such as "write", "read" and
"read & write". The following figure demonstrates how the last
block consists of:
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