When designing pseudorandom generators what should one consider? Here is an example pseudorandom generator $F^t : \{0,1\}^n \rightarrow \{0,1\}^{4n}$. I have no idea what it means, so what does it kindly mean? It is one proposal written in a book for the truly random compression function $t : \{0,1\}^{2n} \rightarrow \{0,1\}^n$
Like how would I design one for truly random compression function such as $t : \{0,1\}^{2n} \rightarrow \{0,1\}^n$?