Schroeder Coder 4.0 | Python Fiddle

import random
map1={1:"A",
      2:"B",
      3:"C",
      4:"D",
      5:"E",
      6:"F",
      7:"G",
      8:"H",
      9:"I",
      10:"J",
      11:"K",
      12:"L",
      13:"M",
      14:"N",
      15:"O",
      16:"P",
      17:"Q",
      18:"R",
      19:"S",
      20:"T",
      21:"U",
      22:"V",
      23:"W",
      24:"X",
      25:"Y",
      26:"Z",
      27:"a",
      28:"b",
      29:"c",
      30:"d",
      31:"e",
      32:"f",
      33:"g",
      34:"h",
      35:"i",
      36:"j",
      37:"k",
      38:"l",
      39:"m",
      40:"n",
      41:"o",
      42:"p",
      43:"q",
      44:"r",
      45:"s",
      46:"t",
      47:"u",
      48:"v",
      49:"w",
      50:"x",
      51:"y",
      52:"z",
      53:"0",
      54:"1",
      55:"2",
      56:"3",
      57:"4",
      58:"5",
      59:"6",
      60:"7",
      61:"8",
      62:"9",
      63:"!",
      64:"@",
      65:"#",
      66:"$",
      67:"%",
      68:"^",
      69:"&",
      70:"*",
      71:"(",
      72:")",
      73:",",
      74:".",
      75:"?",
      76:":",
      77:"'"}

map2={"A":1,
      "B":2,
      "C":3,
      "D":4,
      "E":5,
      "F":6,
      "G":7,
      "H":8,
      "I":9,
      "J":10,
      "K":11,
      "L":12,
      "M":13,
      "N":14,
      "O":15,
      "P":16,
      "Q":17,
      "R":18,
      "S":19,
      "T":20,
      "U":21,
      "V":22,
      "W":23,
      "X":24,
      "Y":25,
      "Z":26,
      "a":27,
      "b":28,
      "c":29,
      "d":30,
      "e":31,
      "f":32,
      "g":33,
      "h":34,
      "i":35,
      "j":36,
      "k":37,
      "l":38,
      "m":39,
      "n":40,
      "o":41,
      "p":42,
      "q":43,
      "r":44,
      "s":45,
      "t":46,
      "u":47,
      "v":48,
      "w":49,
      "x":50,
      "y":51,
      "z":52,
      "0":53,
      "1":54,
      "2":55,
      "3":56,
      "4":57,
      "5":58,
      "6":59,
      "7":60,
      "8":61,
      "9":62,
      "!":63,
      "@":64,
      "#":65,
      "$":66,
      "%":67,
      "^":68,
      "&":69,
      "*":70,
      "(":71,
      ")":72,
      ",":73,
      ".":74,
      "?":75,
      ":":76,
      "'":77}

global encode

def encode():
    key=[]
    #Here, we get the message that is to be encoded, and transform it into a list in convert
    #At the same time we record it's number version in convert2.
    #It is important to know that convert doesn't actually do anything in the long run, its kindof a decoration for reference. 
    print("To begin encoding, please type in the message you want encoded below")
    plaintext=input(": ")
    convert=[]
    convert2=[]
    for letters in plaintext:
        if letters!=' ':
            convert.append(letters)
            convert2.append(map2[letters])
            #print(convert2)
        elif letters==' ':
            pass
    print("Message recieceved successfully. Now we will encode it")
    print("To encode your message, we will need %s letters as a key" % len(convert))
    print("Would you like to enter your own key, or would you like me to get a randomly generated one for you?")
    print("If you have your own key, type 'Have.' If you need me to generate a random one, type 'Dont.'")
    #This code below gets the key for encoding. It's kindof complex, becuase you have a choice
    #Key2 in both scenarios records the letter versions of the key,
    #While Key3 records the letter versions.
    while True:
        key1=input(": ")
        if key1=="Have":
            print("Okay, type it in below")
            key2=input(": ")
            if len(key2)>len(convert):
                print("The key has to be %s characters long(no spaces)" % len(convert))
                print("If you have your own key, type 'Have.' If you need me to generate a random one, type 'Dont.'")
            elif len(key2)<len(convert):
                print("The key has to be %s characters long(no spaces)" % len(convert))
                print("If you have your own key, type 'Have.' If you need me to generate a random one, type 'Dont.'")
            else:
                global key3
                key3=[]
                for letters in key2:
                    if letters!=' ':
                        key2+=letters
                        key3.append(map2[letters])
                #print(key3)    
                break
        elif key1=="Dont":
            print("Okay, getting random letters now...")
            key2=[]
            key3=[]
            for letters in key2:
                if letters!=' ':
                    key3.append(map2[letters])
                elif letters==' ':
                    pass
            for x in range(0,len(convert)):
                z=random.randrange(0,77)
                key2.append(map1[z])
                key3.append(z)
            key4=' '
            counter=0
            for x in range(0,len(convert)):
                key4+=key2[counter]
                key4+=' '
                counter+=1
            #print(key2)
            #print(key3)
            print("%s is your key now" % key4)
            break
        else:
            print("Sorry, I didn't get that. Please try again")

#Now we're actually encoding the message
    print("Encoding...")
    convert3=[]
    counter=-1
    #Here
    for x in range(0, len(convert)):
        counter+=1
        convert3.append(convert2[counter]+key3[counter])
        if convert3[counter]>77:
            convert3[counter]-=77
        #print(convert3)    
    
        
    counter=1
    for x in range(0,len(convert)):
        convert3[counter-1]=map1[convert3[counter-1]]
        counter+=1
    final=' '
    counter=0
    for x in range(0, len(convert)):
        final+=convert3[counter]
        final+=' '           
        counter+=1
    print("Your message now reads: %s" % final)
    print("If you are done with the Schroeder Coder 4.0, type in 'Done'")
    print("If you want to continue encoding or decoding, type in 'Restart'")
    while True:
        y=input(": ")
        if y=="Restart":
            redo()
            break
        elif y=="Done":
            pass
            break
        else:
            print("Sorry, I didn't get that. Try again.")
def decode():
    print("To begin the decoding process, please type in the message that you need decoded.")
    ciphertext=input(": ")
    convert=[]
    convert2=[]
    for letters in ciphertext:
        if letters!=' ':
            convert.append(letters)
            convert2.append(map2[letters])
        else:
            pass
    print("Message received.")
    print("Now we need the key that was used")
    print("Please type the %s character key in below" % len(convert))
    key=input(": ")
    key2=[]
    key3=[]
    for letters in key:
        if letters!=' ':
            key2.append(letters)
            key3.append(map2[letters])
    print("Key received successfully")
    print("Decoding...")
    convert3=[]
    counter=-1
    for x in range(0, len(convert)):
        counter+=1
        convert3.append(convert2[counter]-key3[counter])
        if convert3[counter]<1:
            convert3[counter]+=77
    counter=1
    for x in range(0, len(convert)):
        convert3[counter-1]=map1[convert3[counter-1]]
        counter+=1
    final=' '
    counter=0
    for x in range(0,len(convert)):
        final+=convert3[counter]
        final+=' '
        counter+=1
    print("The message says: %s" % final)
    print("If you are done with the Schroeder Coder 4.0, type in 'Done'")
    print("If you want to continue encoding or decoding, type in 'Restart'")
    while True:
        y=input(": ")
        if y=="Restart":
            redo()
            break
        elif y=="Done":
            pass
            break
        else:
            print("Sorry, I didn't get that. Try again.")
global redo        
def redo():
    print("So, are you encoding a message or decoding one?")
    print("Please type 'encoding' or 'decoding'")
    while True:
        x=input()
        if x=="encoding":
            encode()
            break
        elif x=="decoding":
            decode()
            break
        else:
            print("Sorry, I didn't get that.")
        print("Try again")
print("Welcome to the Schroeder Coder 4.0, now with a better user interface")
redo()

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