Re:Intel Performance Hit 5x Harder Than AMD After Spectre, M...
by alkonaut on Tuesday May 21, 2019 @08:46AM
(#19969601)
Yes it would be extremely difficult to make it so slow that it's not a viable attack vector. So long as it has a known distribution it's not random enough because the mean is the unknown value. I remember too little statistics to understand whether it's possible to add randomness such that the measurements are not distributed in a sense that makes the underlying value not be the mean. It does sound impossible at least.
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Re:Intel Performance Hit 5x Harder Than AMD After Spectre, M...
by celrod on Tuesday May 21, 2019 @10:42AM
(#19970566)
Cauchy distribution.
https://en.m.wikipedia.org/wiki/Cauchy_distribution
The mean of a sample of cauchy(m,s) variables has that same cauchy(m,s) distribution, regardless of sample size.
Meaning to matter how many samples you take, the mean (of the samples) is just as variable as an individual sample.
The mean and variance of the distribution (equivalently, of infinite samples) are undefined. The Cauchy is equivalent to a t distribution with 1 degree of freedom.
Infinite variability will be undesirable for lots of reasons though.