Cpu key made at factory.

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XboxHacker BBS > Xbox 360 > Xbox 360 General Discussion (Moderators: SiliconIce, Arakon, Redline99) > Cpu key made at factory.

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Topic: Cpu key made at factory. (Read 2777 times)

tumba

Member

Posts: 30

Cpu key made at factory.

« on: July 25, 2007, 11:31:21 AM »

I get that the cpukey is "written" at the factory, now i was wondering how it is made (calculated)

is it like the first one that goes trough the plant is called for example 100001 and the second one is 100002?


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vax11780

Hacker

Posts: 94

Re: Cpu key made at factory.

« Reply #1 on: July 25, 2007, 12:41:17 PM »

Only MS knows. You can bet that it isn't a simple sequential calculation, more likely a psuedo-random number or even a true random number.


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tumba

Member

Posts: 30

Re: Cpu key made at factory.

« Reply #2 on: July 25, 2007, 01:10:51 PM »

Thx for the reply mate.

And making a database, for cpu, manufactory date etc wouldnt help since like 0.1% the 360 owners can get ahold of their cpu key.


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tmbinc

Global Moderator
Master Hacker

Posts: 286

Re: Cpu key made at factory.

« Reply #3 on: July 25, 2007, 03:55:23 PM »

The code is in the hypervisor "burn fuses" syscall. It will randomize the number by setting a predetermined number of bits at random positions. I don't think there is a database.

(If Microsoft would want to recover a box, they could just go trough manufacturing mode.)


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Oneohm

Master Hacker

Posts: 100

Re: Cpu key made at factory.

« Reply #4 on: August 06, 2007, 01:34:05 PM »

A good discussion might be on how can we remake the manufacturing mode.


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tumba

Member

Posts: 30

Re: Cpu key made at factory.

« Reply #5 on: August 06, 2007, 03:00:15 PM »

However the timing attack seems to be working wich is really nice, so what would be gained by making a factory-reset?


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tmbinc

Global Moderator
Master Hacker

Posts: 286

Re: Cpu key made at factory.

« Reply #6 on: August 07, 2007, 04:03:10 PM »

The mfg mode requires a challenge with an RSA key, so forget it (unless you find bugs in the mfgbootlauncher.xex).


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Oneohm

Master Hacker

Posts: 100

Re: Cpu key made at factory.

« Reply #7 on: August 08, 2007, 04:52:24 PM »

Not so much finding bugs but reinitialize it like you do on a notebook. I've been finding that they are using a debug board to program the initial boot loader and launch the first firmware programming. The problem is that the debug tool would have to have a firmware of its own to boot the box.