Multiple-image encryption with spatial information prechoosing and cascaded blocks scrambling

Multiple-image encryption by spatial information prechoosing and cascaded blocks scrambling is proposed. The spatial information of secret multiple-image is pre-chosen in advance to effectively reduce the capacity burden of following encryption system. It is conveniently achieved by selecting or compressing the spatial information of multiple images to meet practical demands. Spatially pre-chosen multiple images are reformed to a new image. Cascaded double random phase encoding system is used to encrypt the new image, and the blocks scrambling is operated at the input of each sub-encoding system. Two main advantages are obtained: 1. Since the spatial information prechoosing enables the whole system to afford much larger information capacity, the effective multiplexing capacity is improved greatly; 2. The combination of blocks scrambling and cascaded random phase encoding not only ensure the much higher system security, but also save the key space and easy the key to save and release compared with the methods by each pixel scrambling. Computer simulations have shown the effectiveness of this method.