Optimized process for QR codes multiplexing and encryption

The image multiplexing and encryption process developed in our previous woks has been optimized to store and hide the information contained in the two first chapters of "Don Quijote de la Mancha", which is stored and encoded in 298 QR codes of 512 pix on each side and then compressed into a complex package. The storage is carried out at the Fourier domain by using theta modulation, where the optimal filter and storage method for this type of images are analyzed, looking for memory savings and facilitating the packet encryption. The proposed encryption method implies the superposition of amplitude and phase with chaotic masks and a linear transformation for the image stabilization. Several security tests are carried out to demonstrate the strength of the encryption.