Re:Myths about /dev/urandom (2014)
by kazinator on Wednesday March 25, 2020 @03:13PM
(#22687555)
> About 256 bits of entropy are enough to get computationally secure numbers for a long, long time.
That's just word semantics that depends on how you define "computationally secure".
256 bits of entropy is good enough to get 1 random bit, 256 times. That's the hard fact.
For instance, 256 bits of entropy is not enough to generate more than one 256 bit key for a symmetric cipher. If you generate ten keys from it, you're allocating 25 bits of entropy to each one.
That's just word semantics that depends on how you define "computationally secure".
256 bits of entropy is good enough to get 1 random bit, 256 times. That's the hard fact.
For instance, 256 bits of entropy is not enough to generate more than one 256 bit key for a symmetric cipher. If you generate ten keys from it, you're allocating 25 bits of entropy to each one.