Forum › MIFARE general topics and applications › What is MIFARE Classic 1K Access Bits means? How to calculate and use it? › Reply To: What is MIFARE Classic 1K Access Bits means? How to calculate and use it?
What is nit being explained and frankly, not sure why.
Why is no person explaining the inverted bits and which bits are inverted. Anywell, it took me 4 weeks but I do not want the next person 4 hours. So, to add to the explanation from the mifare team
If you have a close look at the figure 10 of the page 12 (mentioned above, with link), you will see the access condition diagram. Please pay attention to bytes 6 and 7. bytes 6 bites are all inverted and there are denoted with line on top of them. Also, notice that bytes 7, C33, C32, C31 and C30 are all inverted.
An invert in this case means that if the calculated bit is 1, it becomes 0. if the calculated bit is 0, it becomes 1.
There is no invert in bytes 8
Bytes 6 C23 C22 C21 C20 C13 C12 C11 C10 Hex
0 0 0 0 1 0 0 0 X08
Bytes 7 C13 C12 C11 C10 C33 C32 C31 C30
0 1 1 1 0 1 1 1 X77
Bytes 8 C33 C32 C31 C30 C23 C22 C21 C20
1 0 0 0 1 1 1 1 X8F
Why is no person explaining the inverted bits and which bits are inverted. Anywell, it took me 4 weeks but I do not want the next person 4 hours. So, to add to the explanation from the mifare team
If you have a close look at the figure 10 of the page 12 (mentioned above, with link), you will see the access condition diagram. Please pay attention to bytes 6 and 7. bytes 6 bites are all inverted and there are denoted with line on top of them. Also, notice that bytes 7, C33, C32, C31 and C30 are all inverted.
An invert in this case means that if the calculated bit is 1, it becomes 0. if the calculated bit is 0, it becomes 1.
There is no invert in bytes 8
Bytes 6 C23 C22 C21 C20 C13 C12 C11 C10 Hex
0 0 0 0 1 0 0 0 X08
Bytes 7 C13 C12 C11 C10 C33 C32 C31 C30
0 1 1 1 0 1 1 1 X77
Bytes 8 C33 C32 C31 C30 C23 C22 C21 C20
1 0 0 0 1 1 1 1 X8F
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