To decrypt a double transposition, construct a block with the right number of rows under the keyword, blocking off the short columns. Write the cipher in by columns, and read it out by rows.

He explores polyalphabetic substitution ciphers, transposition ciphers, including one developed by the Spartans, connections between ciphers and computer encryption, stream ciphers, ciphers involving ...

Cryptanalyst Jim Gillogly created them using the Playfair, Double Playfair, and Double Transposition ciphers, respectively.

Bernard claims Lukas uses a Ceaser shift cipher to decode the meaning of Salvador Quinn's cryptic message, making it hard not to wonder what it means.