Python中的加密/解密； 解密不起作用

Question

I am trying to decrypt some encrypted .jpg images using python Crypto

def decrypt(input_filename, output_filename, password, cipher):
       ciphers = ['AES_ECB']
       key = generate_key(password)
       #Loading Pixel Data
       im = Image.open(input_filename)
       pix = im.load()
       rgb_im = im.convert('RGB')
       size = im.size
       image = Image.new('RGB', im.size)
       pix1=image.load()
       print "Filesize: " + str(size)
       for x in range(256):
          for y in range (256):
              pixel = rgb_im.getpixel((x, y))
              print pixel#DEBUG
              if cipher == ciphers[0]:
                 print x,y
                 pix1[x,y] = decryptPixel(pixel, key)
     image.save(output_filename)

But I've got this error:

       17             if cipher == ciphers[0]:
       18                 print x,y
  ---> 19                 pix1[x,y] = decryptPixel(pixel, key)
       20     image.save(output_filename)

OverflowError: Python int too large to convert to C long

Could you please help me to figure out the problem?

def decryptPixelComponent(component, key):
     decryptor = AES.new(key, AES.MODE_ECB)
     component_hash = hashlib.sha256(str(component)).digest()
     component = decryptor.decrypt(component_hash).encode('hex')
     #print int(component, 16)
     return int(component, 16)
def decryptPixel(pixel, key):
        (red, green, blue) = pixel
        return (decryptPixelComponent(red, key),
        decryptPixelComponent(green, key),
        decryptPixelComponent(blue, key))

The result from "decryptPixel" is tuple and pix1 is tuple as well. However, when I try to update the pix1 I got this overflow error.

Answer 1

Looking at the "decryptPixelComponent" function it seems you are decrypting the hash value of the pixel ("component_hash"). I think you should try to decrypt without the hash ("component").

def decryptPixelComponent(component, key):
     decryptor = AES.new(key, AES.MODE_ECB)
     component = decryptor.decrypt(component).encode('hex')
     #print int(component, 16)
     return int(component, 16)