William Abel, a mail censor at Iowa's State Prison, Fort Madison, using a hot iron to bring out a secret message written in lemon juice on a letter.Three Lions/Getty Images Humans have had a long ...

People have always wanted to communicate privately. There once was a time when regular ink was secret enough, because not much of the world knew how to read. Then literacy ruined it for everyone, and ...

Coded messages in invisible ink sound like something only found in espionage books, but in real life, they can have important security purposes. Yet, they can be cracked if their encryption is ...

A team of researchers from the Harbin Institute of Technology in China have developed a system by which invisible ink and a basic cipher can be combined with relatively simple AI to create an ...

Invisible ink is back, and it’s better at hiding than ever. A new invisible ink that you can print is harder to reveal than most common cyphers. Liang Li at Shanghai Jiao Tong University in China and ...

Need some gifts for your kids, grandkids, nieces and nephews? More specifically, gifts they won't toss aside as soon as they open them? We've got the goods: Maleden Invisible Ink Pens. These ...

Jean-Michel Basquiat, the late neo-expressionist whose tragic life story inspired a 1996 film, used invisible ink to draw secret figures in at least one of his early paintings, Artnet News reported ...