The serial killer left a cipher with each body that provided clues to the detectives on where to find the next victim.

During WWII a team of code breakers were hired to break a cipher written for the Nazis from their allies.

She developed a secret cipher to write her diary in so that if anyone ever tried to read it, it would look like a jumble of letters.

Government officials typically have a secret cipher used to pass classified information over the internet without detection.

Banks and credit card companies use a cipher to disguise card information and make it harder to steal information.