ib technology

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Sector Trailer Block

The last block of each sector (Blocks 3, 7, 11, 15……59, 63 etc) is the Sector Trailer Block

which contains the two security Key codes (KeyA and KeyB) and the Access bits that define

how the data blocks can be accessed (Read/Write, Read or Write only, as data or Value blocks

and using which key). If KeyB is not used then the last 6 bytes of the Sector Trailer Block can

be used for general data storage. Byte 9 (last byte of Access bits) is not used and can also be

used for general storage. Note that the KeyA (and KeyB) value read back as logical 0’s to

ensure system security.

IT IS STRONGLY RECOMMENDED THAT THE KEY CODES AND THE ACCESS BITS

STORED ON THE MIFARE CARD ARE NOT CHANGED UNTIL THEIR OPERATION

IS FULLY UNDERSTOOD.

Sector Trailer Block

Byte:

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

KeyA and KeyB

The security Key codes are each six bytes long and for successful authentication and

read/write communication the RWD device would have to have one or both keys stored in its

internal memory as well (depending on Access Bit settings). To allow “out-of-the-box”

operation with new Mifare transponders and RWD devices, Transport Key values are pre-

loaded into the transponder memory and also into the RWD memory.

Transport Key values as defined by Infineon are:

KeyA:

0xFF FF FF FF FF FF

KeyB:

0xFF FF FF FF FF FF

Transport Key values as defined by Philips Semiconductors are:

KeyA:

0xA0 A1 A2 A3 A4 A5

KeyB:

0xB0 B1 B2 B3 B4 B5

These KeyA and KeyB values are stored as repeated pairs in the MicroRWD MF device as a

factory default.

If the user intends using other Mifare cards then they may have different transport keys

loaded so the user would have to use the STORE KEY command to load the particular Key

codes into the RWD memory first. Once correct communication is established then Keys and

Access bits can be changed on the card and RWD to suit the users final system requirements.

Access Bits

The access conditions for every data block and sector trailer are defined by three bits (C1, C2,

C3), which are stored in a specific non-inverted and inverted pattern in the sector trailer of the

particular sector. The access bits control the memory access rights using the secret KeyA and

KeyB codes. The access bits can be changed provided the relevant Key(s) is known and the

current access conditions allow this operation.

KeyA (6 bytes)

Access Bits

KeyB (optional)