Hannah handed me a piece of paper with the following string of letters. “Each letter stands for another one,” said Hannah. “Ooh, a substitution cipher!” I thought. But I was stumped. “Is this just one ...

You can make a message secret in countless different ways. One common way is to use a substitution cipher, in which one letter is substituted for another. Another is to employ a transposition cipher, ...

Ars' own Julian Sanchez has deciphered a code embedded into the TV show Fringe. Bad Robot, the production company that created the Fox TV show, has been integrating puzzles and easter eggs into shows ...