Given an RNG and a PRNG.
We define RNG(k) to mean that the RNG produces k random bits.
We define PRNG(k, seed) to mean that the PRNG uses
seed to produce k pseudo-random bits.
Case 1: - Generate n random bits using just the RNG.
bits = RNG(n)
Case 2: - Generate n random bits using the PRNG, and using the RNG as a seed
seed = RNG(n/2)
bits = PRNG(n, seed)
My question is whether there is any practical or even theoretical difference to these in terms of security?
From an outsider, I am assuming that both would seem to be completely random bits.
How does the amount of random data fed to the PRNG from the RNG affect the randomness? My intuition is that if the PRNG is fed less than 256 bits of random data, then the result from the PRNG can be calculated by brute force.