Many old encryption methods are still hard to break today. For instance, cryptanalyzing a Turning Grill (a cipher device already known in the 18th century) is far from trivial. Many other encryption methods of historical importance can nowadays be broken, for instance Enigma messages from WW2, ADFGVX -ciphertexts from WW1, bigram substitutions, cipher slide messages, and double column transpositions.