ib technology
Note that with each memory access the internal logic of the Mifare transponder verifies the
format of the access conditions. If it detects a format error then the entire sector is irreversibly
locked. Since the access bits themselves can be blocked for read/write operations, care must
be taken when cards are being personalised for a particular application or service provider.
Access Bits
Block Affected within a sector
(1k card and lower half of 4k card) (Upper half of 4k card)
C1
C1
C1
C1
0
1
2
3
C2
C2
C2
C2
0
1
2
3
C3
C3
C3
C3
0
1
2
3
Block 0 (Data Block)
Block 1 (Data Block)
Block 2 (Data Block)
Blocks 0-4
Blocks 5-9
Blocks 10-14 (Data Blocks)
(Sector Trailer)
(Data Blocks)
(Data Blocks)
Block 3 (Sector Trailer) Block 15
Note that the Access Conditions for individual blocks can be set on 1k cards and for lower
half of 4k card memory. However for the upper half of 4k cards the Access conditions are set
for groups of five blocks (except for Sector Trailer Block which is still individually set).
Access Conditions
The C1, C2, C3 access bits are stored in a specific non-inverted and inverted pattern in the
sector trailer of the particular sector. These bits control the Access Conditions for every data
block and sector trailer block.
Sector Trailer Block
Byte:
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
KeyA (6 bytes)
Access Bits
KeyB (optional)
Bit 7
6
5
4
3
2
1
0
Byte 6 C2
Byte 7 C1
Byte 8 C3
3
3
3
C2
C1
C3
2
2
2
C2
C1
C3
1
1
1
C2
C1
C3
0
0
0
C1
C3
C2
3
3
3
C1
C3
C2
2
2
2
C1
C3
C2
1
1
1
C1
C3
C2
0
0
0
Byte 9
(
not used
)
Cx
y
= Inverted bit
Transport settings (factory defaults)
Byte 6 (1
1
0
0
1
0
0
1
0
0
1
0
0
1
1
0
1
1
0
1) = 0xFF
1) = 0x07
0) = 0x80
)
Byte 7
Byte 8
0
1
Byte 9
(
not used
28
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