Changing access bits is performed by the same methods as for writing ordinary blocks. You only aim at block 3 of the sector to which you want to change access. Taking into account the specifications of the access bits present in block 3 of each sector (see chapter 8.7.1 from the specification ). A valid combination of control bits must be indicated along with the desired keys (A + B) (read / write operations on Mifare Classic cards are performed at the block level).
, , keyA keyB keyB-only-write, [C1, C2, C3] = [0x78, 0x77, 0x88 ]. A B ( , 0xAA A 0xBB por B), (, 9 ):
byte authBlockData [] = {(byte) 0xAA, () 0xAA, () 0xAA, () 0xAA, () 0xAA, () 0xAA, 0x78, 0x77, () 0x88, 0x00, () 0xBB, () 0xBB, () 0xBB, () 0xBB, () 0xBB, () 0xBB};