PSN and ARM Trust Zone

[freebirds]

I am considering purchasing an OpenPandora which has an ARM Cortex A8 processor or the 1 GHz has an ARM Cortex A9 processor. Unfortunately, ARM Cortex A8 and A9 have ARM Trust Zone. TrustZone is similar to Trusted Platform Module (TPM). Both TrustZone and TPM are used for Digital Right Management and software license management. http://mobile.arm.com/products/processors/technologies/trustzone.php?tab=Why+TrustZone?


Privacy is important to me. I do not want ARM TrustZone or a visible processor serial number (PSN). Does anyone know whether both OpenPandoras have ARM TrustZone and a visible PSN?

 

[notaz]

I'm not aware of anything using that feature for anything here. Kernel does not use it or provide any access to it for programs.

 

[mcobit]

Both are cortex a8 btw.

 

[Exophase]

Hi freebirds,


I saw your posts on ARM's forums about this and I think you might be confused about what TrustZone is. All it is is a separate between a secure and normal execution mode, where the hardware has very controlled/limited means of transitioning from normal to secure mode. It can be used to help strengthen a DRM or other copy protection strategy but by itself it is not DRM, and the important thing is that the hardware vendor (usually probably the SoC manufacturer, unless they expose this stuff to the outside) has to design the system that takes advantage of TrustZone.


None of this is any kind of violation of privacy and has nothing to do with processor serial numbers. If anything it gives facilities that help improve security which is related to improving privacy.. but if the hardware device doesn't use it for anything then it's moot.

 

[freebirds]

Thanks for explaining TrustZone. Can anyone answer my other question whether Pandora has a visible processor serial number (PSN)? Is the PSN written in OTP memory?

 

[slaeshjag]

I can't find it (/proc/cpuinfo reports serial number as a bunch of zeroes)

 

[Exophase]

Searching the OMAP3530 TRM for "serial number" also brings up nothing. I strongly doubt it includes one. I think you'll find hardware tends to not have this sort of thing, since it must cost extra money to uniquely modify every chip like this, even if it's just burning some fuses.