Randomness is not any physical entity and thus "entropy" here is just a word for data that cannot be derived from a system state. When it is not available, the

Randomness is not any physical entity and thus "entropy" here is just a word for data that cannot be derived from a system state. When it is not available, the attacker still has to know the seed of kernel's PRNG to be able to re-create the keys you generated in this state. To this end, she/he has to either sniff some impractically large amount of the PRNG output (and if this is possible your machine is likely already compromised), be able to set it to a given value (see above), or to know it from some prior knowledge, for instance has an image of the VM you use or knows the default value set on boot when no entropy is available whatsoever. In other words, if the seed hasn't leaked it is easier to brute-force the key than to fit the CPRNG output that generated it.