Information security and cryptography: noviembre 2012

Well, here is the code to encrypt the message:

Code:

	import Image #library for use the picture


	archivoi = str(raw_input("nombre de la imagen con extencion: ")) ##take a picture
	imagen = Image.open(archivoi)
	archivom = str(raw_input("nombre del archivo del mensaje maximo 255 caracteres con extencion: ")) ##take a ## file of message
	archivo = open(archivom,"r")
	archivof = str(raw_input("Nombre final de la imagen extencion png: ")) ##take a final picture name


	#nlineas = 0

	mensaje = [] ##list for message
	#contador = 0

	conver = [] ##decimal list of message
	cont = 0 ##cont of conver

	sizem = 0 ##size for some utility

	#pixes = []
	ancho, altura = imagen.size ##dimension of picture
	#imagen2 = Image.new(imagen.mode, imagen.size)
	#f=open("nuevo.bmp","w")
	pixels = imagen.load() ##map of the picture
	contador = 0 ##cont for some utility
	#pixels2 = imagen2.load()

	#dis = 0
	tam = 0 ##cont for the algorithm

	#(r,g,b) = (0,0,0)
	#cont = 0 ##cont for the algorithm

	rgbb = 0 ##identify for some pixel
	identificador = 0 ##value for some caracter for message

	## variable's to save pixels for the algorithm
	a = 0
	b = 0
	c = 0
	## variable's save pixels for the algorithm

	letras = 0
	#recx = []
	#recy = []
	#recl = []

	##part to read message
	for i in archivo.xreadlines():
	dato = i
	mensaje.append(dato)
	cont = cont + len(dato)
	letras = letras + len(dato)

	sizem = len(mensaje) ##save the size of message

	##part to transform to messege at decimal format
	for i in range(sizem):
	size = len(mensaje[i])
	for j in range(size):
	conver.append(ord(mensaje[i][j]))


	#for x in range(ancho):
	# for y in range(altura):
	# pix = pixels[x,y]
	# pixes.append(pix)
	# contador = contador + 1
	#b = b + 1
	#a = a + 1

	####parameters for algoritm
	multi = ancho * altura ##calculate the area of picture in pixels
	##separar = multi/4 ##
	size = int(len(conver))##size of messege in decimal
	separacion = multi/size ##separation of the pixels
	#print "separacion 1",separacion,"multiplicacion :",multi,""
	indicador = 0 ##for some condicion
	alfa = 0 #for some condition
	constante = separacion/4 ##for the algorithm
	control = 0 ##for the algorithm

	#rlist = []
	#pas = 0

	#print "valor de separar:",separar
	cantidades = 0
	#print "altura:",altura,"ancho",ancho,""
	#print "separacion",separacion
	#print "constante: ",constante


	##algoritm

	##read all the map pixels
	for i in range(ancho):
	for j in range(altura):
	(a,b,c) = pixels[i,j] ##save the pixels in three variable

	if cantidades == 0: ## part to save to size of the message
	mod = c % 7 ## and used to the desencripted
	if mod == 1:
	r = size
	pixels[i,j] = (r,b,c) ##r hidden to size in this pixel
	cantidades = cantidades + 1 ##this condicion only one pass time
	#print "pase una sola vez: ",r
	#print "kugari: ",i,"lugar j",j,""
	#print "sixe: ",r
	else:
	if alfa < separacion:
	if cont > 0: ##if the messege have one more caracter
	identificador = conver[tam] ##save the caracter
	##what pixel we used if r or g or b
	if rgbb == 0:
	r = conver[tam] #save the caracter
	pixels[i,j] = (r,b,c) #hidden in the pixel
	tam = tam + 1 #plus for posterior comparation
	cont = cont - 1 ##reset the size of messege
	alfa = separacion
	#recx.append(i)
	#recy.append(j)
	#recl.append(rgbb)
	#print "i: ",i,"j",j,""

	if rgbb == 1: ##its the same the other only change the pixel
	g = conver[tam] ##now is b
	pixels[i,j] = (a,g,c)
	tam = tam + 1
	cont = cont - 1
	alfa = separacion
	#recx.append(i)
	#recy.append(j)
	#recl.append(rgbb)


	if rgbb == 2: ##its the same that others
	B = conver[tam]
	pixels[i,j] = (a,b,B)
	tam = tam + 1
	cont = cont - 1
	alfa = separacion
	#recx.append(i)
	#recy.append(j)
	#recl.append(rgbb)


	if control >= separacion: #used this for jumping pixels
	separacion = separacion + constante/2
	alfa = 0

	control = control + 1 ##for cont message caracter's
	##change the pixle r or g or c
	if rgbb == 0:
	rgbb = 1
	else:
	if rgbb == 1:
	rgbb = 2
	else:
	if rgbb ==2:
	rgbb = 0


	print "contrl",letras
	print "si se puso todos ?:",tam
	print ""
	#contador = 0
	imagen.save(archivof) ##save the new picture


	#print contador
	#print pixels[0,0]
	#print letras
	#print conver

view raw encript.py hosted with ❤ by GitHub

Code:

and this is the code to desencript message:

	##its de same algoritm the only diference its the start, the algoritm read the size
	##of messge of the picture and use the same algoritm to desencript

	import Image
	archivoi = str(raw_input("Nombre de la imagen a desifrar: "))
	imagen = Image.open(archivoi)


	pixel = imagen.load()
	ancho, altura = imagen.size

	mensaje = []

	contador = 0
	letra = 0
	a = 0
	b = 0
	c = 0
	size = 0
	multi = ancho * altura
	separacion = 0
	alfa = 0
	rgbb = 0
	tam = 0
	cont = 0
	control = 0
	constante = 0
	rgbb = 0
	i = 0
	j = 0
	r = 0
	g = 0
	b = 0

	for i in range(ancho):
	for j in range (altura):
	(a,b,c) = pixel[i,j]

	if contador == 0:
	mod = c % 7
	if mod == 1:
	size = a
	cont = int(size)
	multi = ancho * altura
	separacion = multi/cont
	constante = separacion/4
	print "pase una sola vez"
	print "size = ",cont
	#print "altura : ",altura,"ancho: ",ancho,"total: ",multi,""
	#print "separacio: ",separacion
	#print "constante :",constante
	contador = 2;
	else:
	if alfa < separacion:
	if cont > 0:
	if rgbb == 0:
	#(a,b,c) = pixel[i,j]
	mensaje.append(chr(a))
	tam = tam + 1
	cont = cont - 1
	alfa = separacion

	if rgbb == 1:
	#(a,b,c) = pixel[i,j]
	mensaje.append(chr(b))
	tam = tam + 1
	cont = cont - 1
	alfa = separacion


	if rgbb == 2:
	#(a,b,c) = pixel[i,j]
	mensaje.append(chr(c))
	tam = tam + 1
	cont = cont - 1
	alfa = separacion


	if control >= separacion:
	separacion = separacion + constante/2
	alfa = 0

	control = control + 1
	if rgbb == 0:
	rgbb = 1
	else:
	if rgbb == 1:
	rgbb = 2
	else:
	if rgbb == 2:
	rgbb = 0


	print "mi mensaje:",mensaje
	print "size del mensaje:",len(mensaje)