A new multiple ciphering scheme for improving randomness

In this paper, we propose a new multiple ciphering scheme based on a Deficit Weighted Round Robin (DWRR) algorithm to improve the randomness results in the keystream generated by a stream cipher. This scheme has been implemented and tested in a Xilinx Virtex 7 FPGA. The randomness test results of the resulting keystream have proved that this scheme can be used to improve the quality of a stream cipher by increasing the resources used in its implementation a reasonable amount.