RSA code

RSA Code

RSA code is a used to encode messages. The advantage of this type of encryption is that you can distribute the number "n" and "e" (which make up the encryption key) to everyone. The decryption key "d" is kept secret, so only you and a select few can read the encrypted plaintext.

Python

This code was made just for fun, feel free to suggest anything to make it better. The key given here is a toy key, it is easily broken. <lang python>

from tkinter import * import random import time

letter = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q",

         "r","s","t","u","v","w","x","y","z",",",".","!","?",' ']

number = ["01","02","03","04","05","06","07","08","09","10","11","12","13",

         "14","15","16","17","18","19","20","21","22","23","24","25","26","27",
         "28","29","30",'31']

n = 2537 e = 13 d = 937 def decrypt(F,d):

   if d == 0:
       return 1
   if d == 1:
       return F
   w,r = divmod(d,2)
   if r == 1:
       return decrypt(F*F%n,w)*F%n
   else:
       return decrypt(F*F%n,w)
   

def correct():

   for i in range(len(D)):
       if len(str(P[i]))%2 !=0:
           y = str(0)+str(P[i])
           P.remove(str(P[i]))
           P.insert(i,y)

def cipher(b,e):

   if e == 0:
       return 1
   if e == 1:
       return b
   w,r = divmod(e,2)
   if r == 1:
       return cipher(b*b%n,w)*b%n
   else:
       return cipher(b*b%n,w)
   

def group(j,h,z):

   for i in range(int(j)):
       y = 0
       for n in range(h):
           y += int(numP[(h*i)+n])*(10**(z-2*n))
       X.append(int(y))

class App:

   def __init__(self, master):

       frame = Frame(master)
       frame.grid()

       quitbutton = Button(frame, text = "quit", fg ="red",
                           command = root.quit, width = 10)
       quitbutton.grid(row = 0, column =3)

       entry = Entry(frame, width = 100)
       entry.grid(row = 0, column = 0)

       self.contents = StringVar()
       self.contents.set("Type message here")
       entry["textvariable"] = self.contents
       #entry.bind('<Key-Return>',self.Encrypt)

       decrypt = Button(frame,text = "Decrypt", fg = "blue",
                        command = self.Decrypt)
       decrypt.grid(row = 2, column = 1)

       label = Label(frame, text = "# of blocks")
       label.grid(row = 1, column = 1)

       encrypt = Button(frame, text="Encrypt", fg = "blue",
                        command = self.Encrypt)
       encrypt.grid(row =0, column =1)

       nbox = Entry(frame, width = 100)
       nbox.grid(row = 3, column = 0)

       self.n = StringVar()
       self.n.set(n)
       nbox["textvar"] = self.n
       nbox.bind('<Key-Return>', self.set_n)

       nlabel = Label(frame, text = "the value of 'n'")
       nlabel.grid(row = 3, column = 1)

       ebox = Entry(frame, width = 100)
       ebox.grid(row = 4, column = 0)

       self.e = StringVar()
       self.e.set(e)
       ebox["textvar"] = self.e
       ebox.bind('<Key-Return>', self.set_e)

       elabel = Label(frame, text = "the value of 'e'")
       elabel.grid(row = 4, column = 1)

       dbox = Entry(frame, width = 100)
       dbox.grid(row =5, column = 0)

       self.d = StringVar()
       self.d.set(d)
       dbox["textvar"] = self.d
       dbox.bind('<Key-Return>', self.set_d)

       dlabel = Label(frame, text = "the value of 'd'")
       dlabel.grid(row = 5, column =1)

       blocks = Label(frame, width = 100)
       blocks.grid(row = 1, column =0)

       self.block = StringVar()
       self.block.set("number of blocks")
       blocks["textvar"] = self.block
       
       output = Entry(frame, width = 100) 
       output.grid(row = 2, column = 0)

       self.answer = StringVar()
       self.answer.set("Ciphertext")
       output["textvar"] = self.answer

   def set_n(self,event):
       global n
       n = int(self.n.get())
       print("n set to", n)

   def set_e(self, event):
       global e
       e = int(self.e.get())
       print("e set to",e)

   def set_d(self,event):
       global d
       d = int(self.d.get())
       print("d set to", d)
       
   def Decrypt(self):
       #decrypts an encoded message
       global m,P,D,x,h,p,Text,y,w,PText
       P = []
       D = str(self.answer.get())
       D = D.lstrip('[')
       D = D.rstrip(']')   
       D = D.split(',')
       for i in range(len(D)):
           x = decrypt(int(D[i]),d)
           P.append(str(x))
       correct()
       #print(P)
       h = len(P[0])
       p = []
       for i in range(len(D)):
           for n in range(int(h/2)):
               p.append(str(P[i][(2*n):((2*n)+2)]))
           
       Text = []
       for i in range(len(p)):
           for j in range(len(letter)):
               if str(p[i]) == number[j]:
                   Text.append(letter[j])
       PText = str()
       for i in range(len(Text)):
           PText = PText + str(Text[i])
       self.contents.set(str(PText))

   def Encrypt(self):
       #encrypts a plaintext message using the current key
       global plaintext,numP,q,j,z,X,C
       plaintext = self.contents.get()
       plaintext = plaintext.lower()
       numP = []
       for i in range(len(plaintext)):
           for j in range(len(letter)):
               if plaintext[i] == letter[j]:
                   numP.append(number[j])
       #print("Number of letters in message:",len(numP))
       #print("Max block length:",len(str(n))/2)
       #h = int(input("Desired block length:"))
       h = (len(str(n))//2)-1
       q = len(numP)%h
       for i in range(h-q):
           numP.append(number[random.randint(0,25)])
       j = len(numP) / h
       #print(numP)
       X = []
       z = 0
       for m in range(h-1):
           z+=2
       group(j,h,z)
       k = len(X)
       C = []
       for i in range(k):
           b = X[i]
           r = cipher(b,e)
           C.append(r)
       self.answer.set(C)
       self.block.set(len(C))

root = Tk()

app = App(root)

root.mainloop() root.destroy()