Krzysztof Halasa wrote:
quoted text
> David Greaves <david@dgreaves.com> writes:
> 
>> This 5 minute design undoubtedly has flaws but it shows a direction:
>> A basically standard 'De11' PC with some flash.
>> A Tivoised boot system so only signed kernels boot.
>> A modified kernel that only runs (FOSS) executables whose signed hash
>> lives in the flash.
> 
> How hard would it be to reprogramm the flash?

The flash contains hashes signed by the companies private key.

The kernel contains the public key. It can decrypt the hashes but the private 
key isn't available to encrypt them. So although you can put a new application 
onto the system, you can't create a signed hash to write to the flash.

The kernel only runs the executable if the hash is valid.
You can re-write the kernel to avoid this check - but the hardware is Tivoised - 
so you can't run it.

I am not suggesting the kernel should go down the GPLV2 route - I am wondering 
if this is a viable scenario or one of Schneiers'  "movie-plot" threats :)

David

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