Trailer Decoder-Encoder
Access Bytes Decoder

Trailer Block
Decoder-Encoder
Access Bytes Encoder
Trailer Access Bits:
Data 1 Access Bits:
Data 2 Access Bits:
Data 3 Access Bits:





Result (HEX):
Trailer Access Bits Generator
Key A (read-write):

Access Bytes (read-write):

Key B (read-write):

Result (BIN):
Data Access Bits Generator
Data Block (read-write):

For Value Card (increment-decrement):




Result (BIN):

Decode and Encode the access bytes of a RFID card

The trailer block of a RFID card is where the configurations are. The access bytes are located at the seventh-to-tenth byte of the fourth block of any sector, as seen in the image below.

You can reconfigure the access by changing the Access Bit Generators and then copy-paste the resulting bits in the Access Bit Encoder

Note that not all combinations are possible, you can see the possible configurations in the datasheet found HERE in page 11 to 13