Inthispaper,wewilldiscussthedesignandrealizationofalarge-scaleCRNGsanditsapplication to secure communication based on synchronized master-slave large-scale CRNGs. To design the large-scale CRNGs, in the following, we first introduce the modulation of the Duffing map chaotic system such that diversified random chaotic state responses can be obtained for large-scale CRNGs. The original Duffing map system is described by the following system.