Fig. 5. Dynamic 3D code for information encryption.
a Schematic representations of the 3D colour code formation by adding PY16 solution dropwise to quartz containers. Blue, white and orange represent the DMSO, DMSO/H2O, and H2O solutions, respectively. The daylight and fluorescence images of the 3D code are included. The encoded information could be recognized under UV light but could not be identified under natural light. b Schematic representations for the 3D code transformation by means of physical action or introducing solvent. Photographs of the 3D codes under UV light are presented, and the corresponding information was read using a smartphone. c A visual scheme illustrating the information orthogonal encryption process and photographs of new codes combining 2D code and 3D code.