Back to Double Transposition Cipher The keys are correct as stated, but instead of numbering duplicate letters from left to right, Agent Madeleine numbered them from right to left.

Her duress code was to use a double transposition key with precisely 18 letters, so we know this message was not sent under duress.

To decode the cipher at the terminal in the basement in Black Ops 6, you will need to follow a simple technique.

Today’s Math Monday begins a multi-part series on the columnar transposition cipher.