How to do it...

We will use the tkinter module to produce a GUI for the encryptdecrypt.py script.

To generate the GUI we will create the following tkencryptdecrypt.py script:

#!/usr/bin/python3 
#tkencryptdecrypt.py 
import encryptdecrypt as ENC 
import tkinter as TK 
 
def encryptButton(): 
    encryptvalue.set(ENC.encryptText(encryptvalue.get(), 
                                     keyvalue.get())) 
 
def decryptButton(): 
    encryptvalue.set(ENC.encryptText(encryptvalue.get(), 
                                     -keyvalue.get())) 
#Define Tkinter application 
root=TK.Tk() 
root.title("Encrypt/Decrypt GUI") 
#Set control & test value 
encryptvalue = TK.StringVar() 
encryptvalue.set("My Message")  
keyvalue = TK.IntVar() 
keyvalue.set(20) 
prompt="Enter message to encrypt:" 
key="Key:" 
 
label1=TK.Label(root,text=prompt,width=len(prompt),bg='green') 
textEnter=TK.Entry(root,textvariable=encryptvalue, 
                   width=len(prompt)) 
encryptButton=TK.Button(root,text="Encrypt",command=encryptButton) 
decryptButton=TK.Button(root,text="Decrypt",command=decryptButton) 
label2=TK.Label(root,text=key,width=len(key)) 
keyEnter=TK.Entry(root,textvariable=keyvalue,width=8) 
#Set layout 
label1.grid(row=0,columnspan=2,sticky=TK.E+TK.W) 
textEnter.grid(row=1,columnspan=2,sticky=TK.E+TK.W) 
encryptButton.grid(row=2,column=0,sticky=TK.E) 
decryptButton.grid(row=2,column=1,sticky=TK.W) 
label2.grid(row=3,column=0,sticky=TK.E) 
keyEnter.grid(row=3,column=1,sticky=TK.W) 
 
TK.mainloop() 
#End 

Run the script using the following command:

python3 tkencryptdecrypt