decrypt_f.py

from breezypythongui import EasyFrame
from breezypythongui import EasyDialog
from math import log
from tkFileDialog import askopenfilename
from PIL import Image
from Tkinter import Entry,StringVar
from random import randint

import wave as W
from Tkinter import Entry,StringVar


#in YES store some questions whose answer is a yes
YES=["Does the sun rise in the east?","Do two and two make four?","Is water a five lettered word?","Are there twenty four hours in a day?","Can sunlight generate energy?"]
#in NO store some questions whose answer is a no
NO=["Do we humans have sixteen hands?","Is light a three lettered word?","Is b the first letter of english alphabets?","Do all trees hate sunlight?","Can we drink fire?"]

# This are the GUI descriptors
class Decryptor(EasyFrame):
	def __init__(self):
		EasyFrame.__init__(self,title='Decryptor',width = 900,height=300,resizable=False)
		self.addLabel(text = "Welcome to the Decryptor", row = 0, column = 0, columnspan = 2)
		self.addLabel(text="Decrypted message : ", row=1, column=0)
		#self.message=self.addLabel(text='',row=1,column=1)
		self.message=self.addTextArea('',row=1,column=1,height=2, width=20,wrap='word')

		self.addLabel(text="Enter the Password : ", row=2, column=0)
		

		self.Password = StringVar() #Password variable
		passEntry = Entry(self, textvariable=self.Password, show='*').grid(row=2,column=1) 
		
		self.addLabel(text="Select the Image : ", row=3, column=0)
		self.filename=self.addLabel(text="", row=3, column=1)
		self.browse=self.addButton(text="Browse",row=4, column=1,command=self.Browse)
		self.decrypt=self.addButton(text='Decrypt',row=5,column=0,state='disabled',command=self.Decrypt)
		self.hint=self.addLabel(text="Awaiting input.......", row=5,column=1)
		self.captcha_ans=["0"]

	# Function to browse in memory and select file for encryption
	def Browse(self):
		filetypes = [("Image files", "*.png"),("Image files", "*.bmp"),("WAVE files", "*.wav")]
		# only files with above extensions will be visible
		fileName =askopenfilename(parent = self,filetypes = filetypes)
		self.filename['text']=fileName
		self.hint['text']='Awaiting input.......'
		self.decrypt['state']='normal'
		self.message.setText('')

	def Decrypt(self):
		#This creates a dialog box for captcha
		dialog = Captcha(self, self.captcha_ans)
		if dialog.modified()==False or self.captcha_ans[0]=="0":
			self.message.setText("error in captcha")
			return
		self.decrypt['state']='disabled'
		password=self.Password.get()
		

		#Here we declare a few functions which we shall use repeatedly.
		
		# Function which converts a number i.e. linear form to (x,y) coordinates i.e. 2D form using the Hilbert curve.
		def dtoxy(n, d):
			t = d 
			rx = ry = x = y = 0
			s = 1
			while (s < n):
				rx = 1 & (t/2)
				ry = 1 & (t ^ rx)
				x,y = rot(s,x,y,rx,ry)
				x+=s*rx
				y+=s*ry
				t/=4
				s*=2
			return x,y
		# Helping function to dtoxy(), it is needed as the Hilbert curve's individual parts are rotated 
		# with respect to each other.		
		def rot(n,x,y,rx,ry):
			if ry == 0:
				if rx == 1:
					x = n-1 - x
					y = n-1 - y
				x,y = y,x
			return x,y
		# Function which generates a key using the password, which is used to determine the starting point
		# of encoding.	
		def keygen(n):
			key = 0		
			for i in range(len(password)):
				ch=password[i]
				asc=ord(ch)
				key += key + asc*(pow(33,i))
				key = key%(n*n)
			return key
		
		path=self.filename['text']
		#This is when an image file is selected
		if path[-3:]=='bmp' or path[-3:]=='png':
			# opening image using Image module and obtaining dimensions.			
			im=Image.open(self.filename['text'])
			pix=im.load()
			width,height=im.size
			n=2**min(int(log(width,2)),int(log(height,2)))
			
			# generating starting point for encoding.
			key=keygen(n)
			ctr=0
			
			# This function returns the next location to encode. Here it uses 'ct' which is incremented after each character.
			def traverse2(ct):
				return dtoxy(n,ct)
			
			x,y = dtoxy(n,key)		
			flag=1
			mess=''
			cnt=0
			# Iterating through message and decoding it.
			while flag==1 and cnt<=500:
				ascii=''
				#Remember that three pixels store one character
				for i in range(0,3):
					for j in range(0,3):
						pixel=pix[x,y]
						if i==2 and j==2:
							if pixel[2]%2==1:
								flag=0
								break
						else:
							if pixel[j]%2==0:
								ascii+='0'
							else:
								ascii+='1'
						ctr+=1
						x,y=traverse2(ctr+key)
						
				ascii_int=int(ascii,2)
				mess+=chr(ascii_int)
				cnt+=1

			###########################################################		
			self.hint['text']='Program status: Done'
			self.filename['text']=''
			self.message.setText(mess)
			self.captcha_ans=["0"]
		else:
		#This is the case when file selected is an audio file

			audio_path=self.filename['text']
			# opening audio file using wave module (here W)			
			au=W.open (audio_path, 'rb')
			ln=au.getnframes()-44
			# extracting data from file into a list
			data=au.readframes(ln)
			dataT=[ord(byte) for byte in data]
			n=2**int(float(log(ln,2))/2)
			# generating initial location to begin coding
			
			key = keygen(n)
			
			def traverse2(ct):
				x,y=dtoxy(n,ct)
				return n*x+y
					
			ctr = traverse2(key)+44
			curr=dataT[ctr]
			ascii_int='a'
			mess=''
			cnt=0
			while ascii_int<>10 and cnt<=500:
				#here we do the actual decoding
				ascii=''
				for i in xrange(8):
					ascii=ascii+str(curr&1)
					key=(key+1)%n
					ctr=traverse2(key)+44
					curr=dataT[ctr]	
				ascii_int=int(ascii,2)
				mess+=chr(ascii_int)
				cnt+=1
				
			au.close()
		
			self.hint['text']='Program status: Done'
			self.filename['text']=''
			self.message.setText(mess)
			self.captcha_ans=["0"]

#For captcha Dialog Box
class Captcha(EasyDialog):
	
	#Opens a dialog for captcha
	def __init__(self, parent,captcha_ans):
		#Sets up the window.
		self.gamble=randint(0,1)		
		self.captcha_ans=captcha_ans
		EasyDialog.__init__(self, parent, "Captcha")
    
	def body(self, master):
		ques=""
		if self.gamble==0:
			ques="No"
		else:
			ques="Yes"
		self.addLabel(master,text = "Select the question whose answer is "+ques, row = 0, column = 0)
		# Add the button group
		self.correct_pos=randint(0,len(YES)-1)
		self.group = self.addRadiobuttonGroup(master,row = 1, column = 0, rowspan = len(YES))
		if self.gamble==0:
			for i in range(0,len(YES)):
				if i==self.correct_pos:
					self.group.addRadiobutton(NO[i])
				else:
					self.group.addRadiobutton(YES[i])
		else:
			for i in range(0,len(YES)):
				if i==self.correct_pos:
					self.group.addRadiobutton(YES[i])
				else:
					self.group.addRadiobutton(NO[i])

	def apply(self):
		
		selectedButton = self.group.getSelectedButton()
		if (self.gamble==0 and selectedButton["text"]==NO[self.correct_pos]) or (self.gamble==1 and selectedButton["text"]==YES[self.correct_pos]) :
			self.captcha_ans[0]="1"
		self.setModified()


if __name__ == "__main__":
	Decryptor().mainloop()