Abstract: Pseudo Random Number Generator (PRNG) is an algorithm for generating a sequence of numbers. Due to speed in number generation pseudorandom numbers are very important. The increasing application of cryptographic algorithms to ensure secure communications is widely used. So, Here we propose a new reseeding mixing method to extend the system period length and to enhance the statistical properties of pseudo random number generator (PRNG). The reseeding method removes the short periods which are occurred by CB-PRNG and the mixing method extends the system period length by Xoring with ALG. The output sequence of RM-PRNG is used as a key to the encryption and decryption modules. The simulation results are obtained by using Modelsim and Synthesis is observed by Xilinx ISE 10.1.