Playfair Cipher 1.not even the large number of keys in a monoalphabetic cipher provides security 2.one approach to improving security was to encrypt multiple letters 3.the Playfair Cipher is an example 4.invented by Charles Wheatstone in 1854

小型的CA系统，用C++编程，内有说明，可以放心下载-CA small system, with C++ programming, there are instructions, you can rest assured Download