Datasheet

one or both of the keys for each block. That means, that e.g. you can use Key A in your
customer application which is only able to read the data, but use Key B in your internal
application to initialize the cards with full write access.
To identify the access rights for a sector there are three bits, called access bits C1, C2 and
C3. With these three bits eight different modes are possible with these access bits. C1 is the
LSB.
Example:
C1 C2 C3 Mode
1 1 0 3
There are four access rights per sector (one for each three data blocks and one trailer block),
so each block at MiFare 1k and the lower 32 blocks at MiFare 4k has its own three access
bits. At the higher 8 sectors of MiFare 4k five blocks shares one mode.
So depending on wether you set the access bits of a data block or of a trailer block (the
fourth block of each sector) these bits change their meaning.
When writing the access bits of a data block you can define the following things for this
block (this setting is called „block mode“).
 Is the data block readable/writeable and by which key (Key A or Key B or both)
 Is it a value block or a read/write block
 Is the block locked (not read/writable)
Access Conditions Application Access bits Block Mode
Read Write Increment Decrement,
Restore
C1 C2 C3
A|B A|B
1
A|B
1
A|B
1
transport
configuration
0 0 0 0
A|B NEV NEV NEV Read/write Block 0 1 0 2
A|B B
1
NEV NEV Read/write Block 1 0 0 1
A|B B
1
B
1
A|B
1
Value Block 1 1 0 3
A|B NEV NEV A|B
1
Value Block 0 0 1 4
B B
1
NEV NEV Read/write Block 0 1 1 6
B NEV NEV NEV Read/write Block 1 0 1 5
NEV NEV NEV NEV Read/write Block 1 1 1 7
Table 16: Access Bit meaning in „Block-mode“
metraTec MiFare Protocol Guide Page 35 of 38