2

As min entropy of a random variable provides the maximum probability of getting the desired realization of the random variable, which is the most conservative way of measuring the uncertainty of outcomes. Min entropy analysis is required to bound the characteristics of the attacker's perceived observation from the output of the PRNG.

Mitun Talukder
  • 57
  • 5
  • Are you trying to measure it by observing output or by analyzing the PRNG? – bmm6o Mar 08 '16 at 02:06
  • I am trying to measure by observing output of the PRNG. @bmm6o – Mitun Talukder Mar 08 '16 at 03:37
  • 2
    I don't see how this can work. You can't even distinguish a good PRNG from a true random source, so an entropy estimate has to grow without bound as more output is seen. – bmm6o Mar 08 '16 at 05:02
  • If my seed key is k and output length of the PRNG is bounded by 2^k-1,in that case,is it possible to estimate min entropy? @bmm6o – Mitun Talukder Mar 08 '16 at 05:04
  • 2
    You don't even need a calculation: It's 0. – CodesInChaos Mar 08 '16 at 08:42
  • See this answer to a related question: http://crypto.stackexchange.com/a/10408/4241 – bmm6o Mar 08 '16 at 23:01
  • 1
    @CodesInChaos To my annoyance and everyone's on going confusion, no one has sufficiently either equated nor differentiated between cryptographic entropy, information entropy and Kolmogorov complexity. For instance your above comment regarding H(PRNG) = 0 is diametrically opposite to bmm60's linked accepted answer, and I believe Shannon's notion of entropy... – Paul Uszak May 25 '17 at 22:00
  • 1
    @PaulUszak Since this is "cryptography StackExhchange", it's safe to assume that when we talk about entropy, we are talking about cryptographic entropy. I hope that helps lifting your (quote) "on going confusion". – e-sushi Sep 29 '19 at 10:42
  • @e-sushi I get your sentiment but no, not really :-(. Simply inventing a 'special' type of entropy that's tangential to that in all other disciplines doesn't help. "No body knows what entropy really is" as proven by all the questions on this forum. I'll just remain confused along with the rest... – Paul Uszak Sep 29 '19 at 12:37

0 Answers0