Either it is HP print material or the documents from Canon print machine, a secret code is always there to help to investigate department to know the date and time of printing as well as the printer series number.
Many may not know this as the dots are not visible with the naked eye that forms the code. The dots are yellow in color and rectangular is a shape. It is hidden throughout the print page.
All the HP printer software, brother printer software, Canon printer software and every type of printers support the rectangular yellow dots code and security researchers are well aware of it.
Security researcher Rob Graham published a blog post recently explaining how to identify and decode these dots.
He adds the dots are basically position based and can be decoded when plotted against a grid. One can know the specific hours, minutes, dates and numbers from it.
Even though many may be learning about the dots with this article, but it is true the microdots existed for years. Electronic Frontier Foundation (EFF) reveals they have always maintained such code in their color printers.
On its official website, the EFF has a tool link to reveal what information the pattern of dots reveals.
Microdots are not new or limited to just regularly used printers. Bank notes to have codes to safeguard the currency from getting counterfeited.
Data analyst at software consultancy Vector 5, Tim Bennett, said the microdots in print machines are also used to find out whether a certain document is original or forged like if someone says a print page is from 1998, the dots may reveal it was printed just last year and not decades before.
International spies have earlier been found using such envelopes which have tiny dots inside.
During the World War II, some visible dots were used that had secrets and were tough to decode easily.