A coder and a decoder that can be used to send secret messages. the message generated by the machine can't be read by people who don't have the decoder. For example, If I want the machine to generate a message for "hello" then I will type h,e,l,l,o, and then the machine will generate a message. You can type the message in the decoder like x,x,x,x,x,x,x,x,x..... replace the x's with the letters of the message. It is coded in Python.