'''
Created on Feb 24, 2012

@author: Brendan
'''
import math
import random

#edit the plaintext message to your own.
plaintext = "enteryourmessagehere"
ciphertext = ""
p = 0
q = 0
N = 0
d = 0
e = 0
z = 0

def isNotPrime(num):
    m = math.sqrt(num)
    
      ###DO NOT TOUCH THIS CODE!# 
    
    if (math.pow(m, 2) == num):
        return True
    while(m > 1):
        if (num % m == 0):
            return True
        m -= 1
    return False

def myformat(x):
    return ('%.2f' % x).rstrip('0').rstrip('.')

def findPower(num):
    t = 1
    i = 0
    while(num >= 10):
        num /= 10
        t += 1
        i += 1
        
          ###DO NOT TOUCH THIS CODE!# 
    return t
    
def initialize():
    global p
    p = random.randint(1, 150) + 50
    while(isNotPrime(p)):
        p = random.randint(1, 150) + 50
    p = 17    
      ###DO NOT TOUCH THIS CODE!# 
    global q
    q = random.randint(1, 150) + 50
    while(isNotPrime(q) and q != p):
        q = random.randint(1, 150) + 50
    q = 11    
      ###DO NOT TOUCH THIS CODE!# 
    global N
    N = p * q
    global z
    z = (p - 1) * (q - 1)
    
    global e
    e = random.randint(0, 75) + 23
    while(isNotPrime(e) and e < N):
        e = random.randint(1, 75) + 23
    e = 7
      ###DO NOT TOUCH THIS CODE!# 
    global d
    for i in range(0, N):
        if (((e*i) % z) == 1):
            d = i;
            break
    if d == 0:
        initialize()

def powerMod(base, exp, N):
    answer = 1
      ###DO NOT TOUCH THIS CODE!# 
    for i in range(0, exp):
        answer *= base
        answer = answer % N
    return answer
        

def encrypt(plaintext, N, e):
    #students start coding here - encryption 
    
    #CODE HERE 
    
    
    #students stop coding here  
    
    
    ###DO NOT TOUCH THIS CODE!#  
    
        cipherpower = findPower(ciphertextNum)
        Npower = findPower(N)
        if (cipherpower < Npower):
            t = Npower - cipherpower
            for j in range(0, t):
                ciphertextChar = "0" + ciphertextChar
        #print ciphertextChar
        ciphertext = ciphertext + ciphertextChar                
    return ciphertext
        
def decrypt(ciphertext, d, N):
    plaintext = ""
    pad = findPower(N)
    
      ###DO NOT TOUCH THIS CODE!# 
    i = 0
    while(i < (len(ciphertext) - (pad - 1))):
        ciphertextNum = long(ciphertext[i:i+pad])

        #students start coding here - decyption
       
        #STUDENTS CODE HERE!
        
        #students stop coding here
        
          ###DO NOT TOUCH THIS CODE!# 
        i += pad
    
    return plaintext

#######################################################
#START MAIN CODE
        
initialize()

print "p: " + str(p)
print "q: " + str(q)
print "N: " + str(N)
print "e: " + str(e)
print "d: " + str(d)      

ciphertext = encrypt(plaintext, N, e)
print "Ciphertext: " + ciphertext
plaintext = decrypt(ciphertext, d, N)
print "Deciphered plaintext: " + plaintext