The Six Unsolved Ciphers: Inside the Mysterious Codes That Have Stymied the World's Greatest Cryptographers

6 FASCINATING STORIES, 6 MYSTERIOUS CODES

Follow the horrific crimes of the ZODIAC and see the symbol-filled letters he sent to local San Francisco newspapers. Could breaking his code lead to the arrest of this still-at-large serial killer?

Learn how the Declaration of Independence was used to decode part of the BEALE PAPERS. Find the decoder key for the rest of its cipher and a $30 million buried treasure awaits you somewhere in Buford County, Virginia.

See how one man directly challenged the...