He almost certainly used some env with good entropy, he obviously knew what he was doing. Zero chance that these random numbers have a weakness on PRNG side.
Can entropy formula use for calculate position zone of puzzle
SI unit: joules per kelvin (J⋅K−1)
In SI base units: kg⋅m2⋅s−2⋅K−1
https://en.wikipedia.org/wiki/Entropymay be not find directly to key , just want to know zone or area nearly key for using bitcrack or kangaroo to fine again