Disclosed herein are apparatuses and methods for generating pseudorandom numbers by making the existing ANSI and FIPS PRNGs forward secure and eliminating the need for re-keying them. A forward secure ANSI PRNG is created which includes an enhanced block cipher that is non-invertible even if the key becomes known and a function of the block cipher used in the existing ANSI PRNG. Additionally, the forward secure ANSI PRNG includes an enhanced next state that allows previous states to remain secret even when the key and the current state become known. A forward secure FIPS PRNG is created which includes a computation of an enhanced next state that is noninvertible.