3 ms·
The entropy value was designed to be a known underestimate, not an accurate estimate of the entropy available. What that in mind, zero is ok as a value. You m
by jlokier 7y ago
The entropy value was designed to be a known underestimate, not an accurate estimate of the entropy available.
What that in mind, zero is ok as a value. You may not be able to calculate the state of /dev/random given the tools and techniques available to you, but that doesn't make zero an incorrect lower bound on what you could mathematically calculate from the extracted data.
- tptacek 7y agoIn reality, the entropy estimate is of no value. See Ferguson and Schneier, who have a chapter on this. The meaningful states of a CSPRNG are "initialized" or "not". Once initialized, there is never a diminishment of "entropy".
- jlokier 7y agoI agree with that, subject to the assumption that your CSPRNG is built on CS-enough primitives. (What I disagreed with is the argument made by the GP, not you, that the Linux entropy value was incompatible with their in-principle mathematical description of "true" entropy. Pretty irrelevant to real cryptography.)