diffusion

The term diffusion is used in encryption, acoustics, printer reproduction, lighting technology, and last but not least in semiconductor manufacturing.

1. Besides confusion, diffusion is the second principle for the development of encryption algorithms. In this method, the redundancy of the text is spread over the ciphertext by swapping plaintexts.
2. In acoustics, diffusion stands for atomization. In this process, sound is reflected from walls in an irregular manner, i.e. diffusely, usually several times. The type of reflection is distributed in all directions and is purely random. Part of the sound energy is absorbed, another part is reflected and influences the room sound. Diffuse sound depends, among other things, on the nature of the reflecting walls and occurs more in the case of hard and round. In sound reinforcement, there are special components, the diffusors, with which the diffusion of sound is deliberately influenced. Diffusors are regularly arranged elements that reflect the incident sound according to certain patterns in as many directions as possible, thus softening it.
3. In printing processes, diffusion stands for the reproduction of continuous color values. As a rule, only two color values are available for the reproduction of color values, namely light and dark. Dithering with the reproduction of spatially extended rasters is one process for printing continuous color gradients. In another, the print dot size is changed, which is only possible in a limited way, and with a third, error diffusion, the image dot is assigned light (white) or dark( black) according to a fixed scale. Since the assignment of a gray value is always subject to an error, the process is called error diffusion. The error that arises during the assignment is distributed over the subsequent pixels using an algorithm.
4. In lighting technology, diffuse light is the dispersion of a light source by means of a diffuser in order to achieve a more pleasant illumination. Light diffusion, which is used for lighting in living spaces and workplaces, reduces glare.
5. In chemistry, diffusion is the spread of one substance into another based on the concentration gradient. In this diffusion, particles of one substance diffuse into another; they spread out evenly. In the case of silicon, diffusion occurs with dopant atoms, in which these spread through the silicon lattice and occupy missing silicon atoms.