RFID card password verification problem

fish001

RFID card password verification problem [Copy link]

I recently wrote a program to operate the radio frequency card. I encountered some problems and would like to share them. Radio frequency card introduction: Radio frequency cards are mainly divided into 16 sectors, each sector has 4 modules, of which the fourth module of the sector is the password block, and the others are data blocks (except the first sector, because the first module of the first sector stores the card number of the radio frequency card). The password block of the radio frequency card is divided into three parts: 1: Password area A (6 bytes) default value (0xff, 0xff, 0xff, 0xff, 0xff, 0xff) 2: Password area for controlling read and write operations (4 bytes) 3: Password area B (6 bytes) When modifying the password of the radio frequency card, it is best to only modify the password area 1, and use the modified password area 1 for verification. Password area 2 and password area 3 use the original default, and it is best not to make changes. Generally, the default values of password area 2 are (0xff, 0x07, 0x80, 0x69) and password area 3 are (0xff, 0xff, 0xff, 0xff, 0xff, 0xff). At first, I only changed password area 1 and directly passed in 6 bytes. However, it passed when I used the new password for verification, but neither reading nor writing worked. After repeated attempts, I found that when changing the password, I also need to pass in the default area 2 and area 3. If the modified password is (0x00, 0x00, 0x00, 0x00, 0x00, 0x00), then the password should be 16 bytes, including the modified password + area 2 + area 3. When verifying, I can use the first 6 bytes.