A pseudo-random number generator (PRNG) for a cryptographic processing system is disclosed in which the PRNG is reseeded at each instance of input entropy and in which a standard timestamp variable used in determining random sequence outputs is replaced with a running counter. The method employed by the PRNG demonstrates increased resistance to iterative-guessing attacks and chosen-input attacks than those of previous technologies. The PRNG is suitable for use in, for example, a mobile telephone system for accomplishing secure communications.