Access IS LSR118 - 7.8 MIFARE Decrement Value Block (Key A or B)

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7.7.2 MIFARE response bytes
MIFARE response bytes
Response header
Response code
Block number
Status bytes
[0x00]
Any one of the following
values
(Command code + 1)
[0x0D] or [0x1D]
[0x4D] or [0x5D]
[0x8D] or [0xCD]
[0x9D] or [0xDD]
Block number
[0x90][0x00]
Success
[0x69][Status Code]
Failure
Refer to page 55 for information on MIFARE failure status codes.
7.7.3 Example
This command successfully increments the previously created value field at block number 4 by
[0x00000001]. The command uses the loaded key and authenticates against Key A in the media.
USB
Command:
[0x00][0x4C][0x04][0x00][0x00][0x0][0x01]
Response:
[0x00][0x4D][0x04][0x90][0x00]
Serial
Command:
[0x6F][0x07][0x00][0x00][0x00][0x00][0x00][0x00][0x00][0x00]
[0x00][0x4C][0x04][0x00][0x00][0x00][0x01]
Response:
[0x80][0x05][0x00][0x00][0x00][0x00][0x00][0x00][0x00][0x00]
[0x00][0x4D][0x04][0x90][0x00]
7.8 MIFARE decrement value block (key A or key B)
Use this command to authenticate the specified MIFARE block against the MIFARE media’s internal
Key A or B and then decrement the value block.
You must load the MIFARE key using MIFARE load key (on page 40) before sending this command.
The specified block number must also be a value block or the command will fail. To create a value
block, use the use the MIFARE create value block (key A or key B) command (on page 44).
Note: This command is NOT applicable to MIFARE Ultralight cards and fails if executed on
Ultralight cards. Ultralight cards do not support value blocks.
7.8.1 MIFARE command bytes
MIFARE command bytes
Command header
Command code
Block number
Initial value
[0x00]
[0x0E]
Decrement value block (Key A)
Block number
32-bit
decrement
value
(MSB first)
[0x1E]
Decrement value block (Key B)
[0x4E]
Authenticate and decrement value block (Key A)