This was one of the most secure hand ciphers used in the Second World War. It was used by both the Allies and the Axis, and served both well. Its main weakness was that if the attacker intercepted two ...

The envelope arrived at the San Francisco Chronicle in November 1969 without a return address, its directive to the recipient, in handwriting distinctively slanted and words unevenly spaced, to ...

The keys are correct as stated, but instead of numbering duplicate letters from left to right, Agent Madeleine numbered them from right to left. You may want to complete the decryption yourself before ...