我正在进行LSB隐写术，对于字符串的每个字符，我将其转换为二进制，然后将每一位分别转换为红色，绿色，蓝色像素。因此，每个角色占用几乎2个像素半（第3个像素的红色和绿色）。
在编码时，它可以完美工作，但在解码时，它不仅仅适用于前两个角色。
我该如何解决？
def encode_image(img, msg):
"""
mettre les quantites du (r,v,b) dans un tuple
cacher le message sous carateres binaires
"""
#Longueur du message: L
L = len(msg) + 1
# longueur max du message (255 car)
if L > 255:
print("texte trop long! (ne pas depasser 255 caracteres)")
return False
if img.mode != 'RGB':
print("l image doit etre de type RVB")
return False
# on utilise une copie de l image pour cacher le texte
encode = img.copy()
row=column=0
colonne, ligne = img.size
r, v, b = img.getpixel((column, row))
encode.putpixel((column, row), (L, v , b))
for c in (msg):
print ("\n\t\t\t\tCaractèr:\t ", c)
binary_char = bin(ord(c))[2:]
if (len(binary_char) != 8):
difference = 8 - len(binary_char)
x = 0
for x in range(0, difference):
binary_char = "0" + binary_char
print ("\n\t\t\t\tCaractère binaire:\t ", binary_char)
i = 0
pic = 0;
column+=1
if(column == colonne):
row+=1
column=0
for char in (binary_char):
r, v, b = img.getpixel((column, row))
print("\nRouge=\t",r,"\nVert=\t",v,"\nBleu=\t",b)
binary_red = bin(r)[2:]
if (len(binary_red) != 8):
difference = 8 - len(binary_red)
x = 0
for x in range(0, difference):
binary_red = "0" + binary_red
binary_blue = bin(b)[2:]
if (len(binary_blue) != 8):
difference = 8 - len(binary_blue)
x = 0
for x in range(0, difference):
binary_blue = "0" + binary_blue
binary_vert = bin(v)[2:]
if (len(binary_vert) != 8):
difference = 8 - len(binary_vert)
x = 0
for x in range(0, difference):
binary_vert = "0" + binary_vert
print("\nBinary Rouge=\t",binary_red,"\nBinary
Vert=\t",binary_vert,"\nBinary Bleu=\t",binary_blue)
if( i % 3 == 0):
new_binary_red = binary_red[:7] + char
new_red = int(new_binary_red, 2)
pic+=1
i+=1
print("\nNew binary Rouge=\t",new_binary_red)
print("\nNew Rouge=\t",new_red)
elif( i % 3 == 1):
new_binary_vert = binary_vert[:7] + char
new_vert = int(new_binary_vert, 2)
pic+=1
i+=1
print("\nNew binary Vert=\t",new_binary_vert)
print("\nNew Vert=\t",new_vert)
elif( i % 3 == 2):
new_binary_blue = binary_blue[:7] + char
new_blue = int(new_binary_blue, 2)
pic+=1
i+=1
print("\nNew binary Bleu=\t",new_binary_blue)
print("\nNew Bleu=\t",new_blue)
print("\nPixel=\t",pic,"\nLigne=\t",row,"\nColonne=\t",column)
if( pic == 3):
encode.putpixel((column, row), (new_red, new_vert, new_blue))
pic = 0
column+=1
if(column == colonne):
row+=1
column = 0
return encode
def decode_image(img):
colonne, ligne = img.size
#print("\nrow:\t", ligne,"\ncolonne:\t",colonne)
i=j=compteur=0
r,v,b = img.getpixel((j,i))
L=r - 1
msg = ""
c=''
for compteur in range(L):
pic = 0;
j+=1
if(j == colonne):
i+=1
j=0
char_binaire = ""
taille = len(char_binaire)
for taille in range(0, 8):
print("\nrow:\t", i,"\ncolonne:\t",j)
r,v,b = img.getpixel((j,i))
print("\nRouge=\t",r,"\nVert=\t",v,"\nBleu=\t",b)
binary_red = bin(r)[2:]
if (len(binary_red) != 8):
difference = 8 - len(binary_red)
x = 0
for x in range(0, difference):
binary_red = "0" + binary_red
binary_blue = bin(b)[2:]
if (len(binary_blue) != 8):
difference = 8 - len(binary_blue)
x = 0
for x in range(0, difference):
binary_blue = "0" + binary_blue
binary_vert = bin(v)[2:]
if (len(binary_vert) != 8):
difference = 8 - len(binary_vert)
x = 0
for x in range(0, difference):
binary_vert = "0" + binary_vert
print("\nBinary Rouge=\t",binary_red,"\nBinary
Vert=\t",binary_vert,"\nBinary Bleu=\t",binary_blue)
if (taille % 3 == 0):
char_binaire = char_binaire + binary_red[7:]
pic += 1
elif (taille % 3 == 1):
char_binaire = char_binaire + binary_vert[7:]
pic += 1
elif (taille % 3 == 2):
char_binaire = char_binaire + binary_blue[7:]
pic += 1
print("\nBinary Caracter=\t",char_binaire)
print("\nPixel=\t",pic)
if ( pic == 3):
pic = 0
j+=1
if(j == colonne):
i+=1
j = 0
c = chr(int(char_binaire, 2))
msg = msg + c
print("\nCaracter=\t",c,"\nMessage=\t",msg)
return msg
choix=int(input("Choisir : \n 1 => Encoder l'image \n 2 => Decoder l'image
\n 99 => Quitter \n Votre choix: \t"))
while( choix != 99):
if choix == 1:
# vous pouvez donner le chemin complet de l image
fichier_original_image=input("Donnez le chemin complet de l'image à
crypter:\t")
img = Image.open(fichier_original_image)
# le mode de l image doit etre 'RVB'
# creer un nouveau document pour l image modifiee/codee
pos1 = fichier_original_image.rfind('\\')+1
pos2 = fichier_original_image.rfind('.')
pos2 = pos2 + len('.bmp')
image_name = fichier_original_image[pos1:pos2]
image_encode = "enc_" + image_name
chemin_image = fichier_original_image[:pos1]+image_encode
# on ne depasse pas 255 caracteres
secret_msg = input("Donnez le message à cacher: \t")
img_encode = encode_image(img, secret_msg)
if img_encode:
# save the image with the hidden text
img_encode.save(chemin_image)
print("{} saved!".format(image_encode))
# l image sauvegardee dans le chemin du programme
import os
os.system('cygwin' + image_encode)
elif choix == 2:
# retourner le message secret
chemin = input("Donnez le chemin complet de l'image à decrypter: ")
encode_img = Image.open(chemin)
hidden_text = decode_image(encode_img)
print("Texte caché:\n{}".format(hidden_text))
choix=int(input("Choisir : \n 1 => Encoder l'image \n 2 => Decoder l'image \n 99 => Quitter \n Votre choix: \t"))