Hey there guys and gals,
so I am right now studying topics regarding pseudorandomness.
I was wondering why, for example with CBC-MAC oder a regular CBC blockcipher, we use padding instead of a PRG. If the block size is not a whole multiple of the clear text m, we could just use a PRG with the seed as the last block of m ? Or would that be "deterministic" since the seed is not selected truly random ? If so what is the point of enlarging an already random generated seed ? We could just create a new random number with the wanted length ?
Which brings me to point 2, I generally can not think of an example where a PRG is used. I know theres a method in java that acts the same way to generate a number between a lower and an upper bound, but in terms of crypto I am clueless.
A pseudorandom function / pseudorandom permutation is only "truly" random, when the key is picked randomly ? Same goes for the seed of a PRG ?
I know this might be all over the place :) I appreciate your time & effort