Nonsecret codes -- book code -- dictionary code -- Codetalking -- Pig Latin -- Turkish Irish -- Caesar cipher -- St. Cyr slide -- Keyboard cipher -- Morse code -- Semaphore -- Pigpen cipher -- Rosicrucian cipher -- Date shift cipher -- Greek square cipher -- Greek skytale -- Rail fence cipher -- Route transposition cipher -- Codebreaking -- Early concealment techniques -- Null cipher -- Cardano grille -- Word grille -- Space code -- Playing card code -- Dot cipher -- Line cipher -- Zigzag cipher -- Invisible inks.