The Lighthouse Cipher
A three-stage challenge combining a Polybius square with columnar transposition, wrapped in a nautical theme. Can you decode the keeper's final log entry?
Visit Polybius exhibit →Breaking the Confederate Vigenère — Step by Step
A detailed walkthrough of Kasiski examination applied to a real Confederate cipher message intercepted near Vicksburg in 1863.
Visit Confederate Vigenère exhibit →The Forgotten Women of Room 40
While Bletchley Park's women codebreakers gained recognition, the women who worked in the Admiralty's Room 40 during WWI remain largely unknown.
Visit Machines Hall →Enigma Daily Challenge
Every day, a new Enigma-encrypted message with authentic rotor and plugboard settings. Your mission: find the day key and decrypt the dispatch.
Visit Enigma exhibit →Hill Cipher: When Linear Algebra Attacks
Matrix inversion mod 26, known-plaintext recovery of the key matrix, and why the Hill cipher's linearity is its fatal flaw.
Visit Hill cipher exhibit →The Uncracked Dorabella Cipher
Edward Elgar's 1897 cipher letter to Dora Penny remains unsolved after 125 years — an 87-character mystery in 24 unique symbols.
Visit Substitution exhibit →Submit a Fact or Write-up
Have a verified historical fact, a challenge solution write-up, or a cipher puzzle to share? Send it to the museum curators for review.