Re: the cold-boot attack

On Sat, Feb 23, 2008 at 11:23:16PM +0100, markus reichelt wrote:

> > there is aonether option that is well doable with todays
> > technology.  On a multi-CPU machine run a dedicated
> > noninterruptible kernel thread on one of the cores which keeps
> > essential parts of the key in CPU registers at all times.
> 
> How do you prevent the OS from using this CPU? If it's a dualcore
> system, ok, but what about quadcore+ systems? I agree it's possible
> (and takes the idea of using "cache" for key storage to an extreme
> level).

not sure if it can be done fully portably by the means of todays OS
but CPUs can be left unused by OS.

> Has it been achieved to access CPU#1 regs from a thread running on
> CPU#2, f.e., a) without significant speed penalties and b) at all? 

the idea was to have that thread do all encryption tasks as well, so
no need to access registers across CPUs

Richard

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