[Cryptography] Speculation re Intel HW cockup; reqs. OS rewrites & slow execution

[Bill Frantz]

On 1/4/18 at 5:06 PM, nico at cryptonector.com (Nico Williams) wrote:

>Speculative execution is necessarily side-effect-having by its potential
>cache thrashing impact and ability to be impacted by cache thrashing.
>This necessarily creates side-channels.  It seems unavoidable except by
>having sandboxed caches, but that's probably not an option for many
>reasons (including power consumption).

I can imagine speculative execution which does not proceed if 
the needed data is not already in the cache. If the caching is 
working as advertised, this will have a small effect on overall 
performance. (MOst of the data needed is already in the cache.) 
It will defeat the attacks which use cache presence or absence 
as a signaling path.

Cheers - Bill

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