Nano-Painting: Encryption With Colours

Nano-Painting: Encryption With Colours

A few years ago, a Professor (Harald Hass) stood on a stage for his Ted talk:

The talk broke new ground and showed how we could transmit data over light — and now defined as Pure LiFi. Now, a groundbreaking paper outlines how we could implement encryption using light with different colours [here], and then reveal the decryption in a form that can be visual to the human eye:

In the paper, the research team projected light into silver nanostructures from defined directions, and where a range of colours of light was reflected back — known as a chiral response. The polarization of the light (such as horizontal, vertical or diagonally) created different light reflection patterns, too:

These colours can then be defined with numeric values and the numeric values converting into ASCII coding. The coding uses a quaternary code of 0, 1, 2 and 3 (and where these codes can represent different colours). We thus have two bits represented in each code. A character “A”, could then be represented by four quaternary codes, such as 0, 2, 1, 3:

With the chromo-encryption technique, only when there is the right combination of the colours of the light and its polarization in the right direction will it reveal a secret message. The research team then used Picasso’s Mediterranean Landscape to replace the pixels in the image with silver nanostructures and were able to reveal the picture only when light is polarized in a given direction. This produces “nano painting”. We can see in the following at the light polarized with (h) reveals the image:

The great thing with the technology is that the encryption result can be revealed to the human eye. There are thus many applications that relate to where a human must check for the validity of an object, such as adding encryption onto surfaces of printed content, such as for IP/copyright protection.