ZigZag

The Zigzag Cipher is a classical transposition cipher that rearranges the letters of a message by writing them in a back-and-forth, diagonal pattern across multiple rows, then reading them off row by row to produce the ciphertext. It is most commonly known today through its rail-based variant, which was popularized in the 19th century and is often associated with early military and telegraph use.

The Kangaroo cipher, sometimes referred to as a jumping key cipher, is a classical polyalphabetic cipher whose exact origins are uncertain, but which appeared in cryptographic literature and practice in the late 19th century to early 20th century. Unlike fixed-key polyalphabetic systems such as the Vigenère cipher, the defining feature of the Kangaroo cipher is that the key does not advance in a simple, linear fashion. Instead, it “jumps” through the key according to a predefined rule, much like a kangaroo hopping unevenly forward.

The Transposition cipher is a classical encryption method that conceals a message by rearranging the positions of its letters rather than changing the letters themselves. It is one of the oldest families of ciphers, with documented use dating back to ancient civilizations, including examples attributed to Spartan military practices such as the scytale around 5th century BCE. Unlike substitution-based systems, a Transposition cipher preserves the original characters of the plaintext but alters their order according to a specific rule or key.