# Security proof for PRNG

Could you help to find an example of where the next kind of proof is performed, please? "if we can distinguish the randomly generated bits of a PRNG from a random sequence, then we can distinguish the underlying block cipher/permutation from a random permutation"

• A construction where you would see this kind of proof summary is counter mode with a fixed start using the random input as the key, i.e. $G(x)=E_x(0)\|E_x(1)\|E_x(2)\|E_x(3)\|\ldots$
– SEJPM
Jul 7 at 8:37