Maynard Handley (name99.delete@this.name99.org) on December 11, 2018 4:32 pm wrote:
> Anon (no.delete@this.email.com) on December 11, 2018 4:21 pm wrote:
> > Maynard Handley (name99.delete@this.name99.org) on December 11, 2018 7:20 am wrote:
> > >......
> > > The crypto has to be appropriate to the problem. This is NOT the equivalent of network crypto.
> > > For example, suppose the equivalent of a random key burned into the device is XOR'd with everything
> > > going into and out of an MRAM cache (maybe also XOR-in the relevant addresses).
> > > Is that good enough? On the off-chance that someone could extract the contents
> > > of the MRAM cache (which may or may not be true?) the assumption is always
> > > that they CANNOT extract the contents of these sorts of hardware keys.
> >
> > Such a scheme would be about as secure as writing a key on a yellow postit on your monitor.
>
> Why do you say that?
> This is not a situation where one can watch a constant stream of data and extract statistics.
> My threat model is that someone steals a laptop, delids the chip, and has access to the
> frozen contents of the MRAM data. Not even the cache tags, just a collection of lines
> of data; and not a constant, changing, stream of data as the CPU executes.
>
> Is that the threat model you believe you have in mind? If not, well, we are not discussing the same thing.
>
>
> > Unfortunately the fact is that good encryption is hard, and somewhat computationally involved.
> >
> > Not to mention the fact that with a static key, both ends
> > need that key, as as soon as it leaks, its game over.
>
> Slogans are great. But the relevance of this one is not especially clear to me.
>
> I would be the first to admit that I know very little about crypto.

Then how about you shut the hell up and stop polluting?