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#1 2020-01-14 12:50:27

hayabusa
Contributor
From: Australia
Registered: 2019-08-27
Posts: 9

about Block 3(diversified key)

Hi guys,

I now have a question about block 3.
My understanding about Block3(diversified key) is calculated with CSN & Auth key.

Could someone explain why we need old-div-key/old Auth key to get new-div-key/XOR?
and
 
-> found answer from this forum.

If we knew old-CSN + old-block3-data(without old Auth key), can we get new div key/XOR?
what I mean is, old CSN + old XOR(block3 data) can calculate old Div key?
(In this cace, we dont know old Auth key)
 
-> I realised this was stupid question after trying calc div key.

I still dont understand why using XOR when you write KD/KC in block3/4.
But fairly now understand how it works.

Again, thank you guys!

pm3 --> hf iclass calc n aeaeaeaeaeaeaeae s 1111111111111111
[+] Old div key : 7E 43 26 0A D1 95 01 A0
[+] New div key : 05 DE 48 7D C3 3C 76 BB
[+] Xor div key : 7B 9D 6E 77 12 A9 77 1B

pm3 --> hf iclass calc o eaeaeaeaeaeaeaea n aeaeaeaeaeaeaeae s 1111111111111111
[+] Old div key : 67 39 81 94 01 7E 3A B8
[+] New div key : 05 DE 48 7D C3 3C 76 BB
[+] Xor div key : 62 E7 C9 E9 C2 42 4C 03

Last edited by hayabusa (2020-01-15 10:56:05)

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