The Cipher Exchange (CE) is that department of The Cryptogram that deals with ciphers which are NOT simple substitutions of the Aristocrat/Patristocrat variety. Here you will find the fruits of several hundred years of development of cryptography, as cryptanalysts discovered new ways to attack a cipher, and the encipherers then complicated the ciphers to compensate. Some of the ACA systems were used historically in precisely the form we use; some are simplified to highlight unique aspects of that cipher type; and some were invented by ACA members. CE ciphers given in The Cryptogram are all solvable by pencil and paper methods, although computers and other mechanical aids are often used to assist. The ciphers are printed in approximate order of difficulty (as determined by experience) in The Cryptogram. They are listed in alphabetical order below, together with the length recommended for a suitable plaintext.
Cipher Types –