Patent ID: 7809136

Claim:
A forward secure pseudorandom number generator, comprising: a processor; a seeded hash function H K ; an iteration integer i, i≧1; an enhanced next state Fs′ i provided by the processor for each iteration integer i, wherein the enhanced next state Fs′ i is non-invertible; an enhanced pseudorandom number generator output Fy′ i provided by the processor for each iteration integer i, the enhanced pseudorandom number generator output Fy′ I having a block length n, wherein the enhanced pseudorandom number generator output Fy′ i is calculated by the processor and is a function of at least one auxiliary input t i ; and an input device, wherein the at least one auxiliary input t i is received by the processor via the input device, Fy i ′=H K ((Fs′ i−1 +t i )mod 2 n ), and Fs′ i =((H K ((Fs′ i−1 +Fy′ i +1+t i )mod 2 n )+Fs′ i−1 +Fy′ i +2)mod 2 n ).