5-8.在MifareS50中,如果第2区的访问控制码为FF 08 70 69 ,则该区块1和3的访问控制条件是什么?
解答:
在存储控制中每个块都有相应的3个控制位,定义如下表5-4
表5-5访问控制码的结构
控制位(块号 X=0~2 |
控制条件(对块0,1,2) | |||||
C1X |
C2X |
C3X |
Read |
Write |
Increment |
Decrement,Transfer,Restore |
0 |
0 |
0 |
KeyA|B |
KeyA|B |
KeyA|B |
KeyA|B |
0 |
1 |
0 |
KeyA|B |
Never |
Never |
Never |
1 |
0 |
0 |
KeyA|B |
keyB |
Never |
Never |
1 |
1 |
0 |
KeyA|B |
keyB |
keyB |
KeyA|B |
0 |
0 |
1 |
KeyA|B |
Never |
Never |
KeyA|B |
0 |
1 |
1 |
keyB |
keyB |
Never |
Never |
1 |
0 |
1 |
keyB |
Never |
Never |
Never |
1 |
1 |
1 |
Never |
Never |
Never |
Never |
表5-6存取控制位为FF 08 70 69对应的二进制码
|
Bit7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
Byte6
|
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
Byte7
|
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
Byte8
|
0 |
1 |
1 |
1 |
0 |
0 |
0 |
0 |
Byte9 |
0 |
1 |
1 |
0 |
1 |
0 |
0 |
1 |
那么对应每个块的存取控制位如下:
块0:001 块1:001 块2:001 块3:000
由表5-5得:区块1和区块3的访问控制条件是
<1>区块1的存取控制位为C11 C21 C31=001时,验证密钥A或密钥B正确后可读;不可写;不可加值;验证密钥A或密钥B正确后可进行Decrement,Transfer, Restore操作。
<2>区块3的存取控制位为C13 C23 C33=000时,验证密钥A或密钥B正确后可读;验证密钥A或密钥B正确后可写;验证密钥A或密钥B正确后可加值;验证密钥A或密钥B正确后可进行Decrement,Transfer, Restore操作.