After iOS 10 officially launching on Sept. 13 2019, we can use the invisible ink feature in Iphone, which can be applied both to photos or other images and regular texts, obscures your message in visual noise. To read the message, all you have to do is swiping your finger across the dots, all will be revealed.
Just thinking, when in the playing cards games, you can receive the invisible information sent from your friend who get the game results from the background poker analyzer which read and analyzed the invisible ink edged barcode marked deck cards, and others can not read anything. It means you can know your chance to win the games and then it is very simple for you to make a decision for how to bet.
Do you have Iphone? If you are interested in it, try it now!