lsb

from PIL import Image

def extract_bits(color, bitmask):
    bitmask_len = len(bin(bitmask)[2:])
    extracted_bits = bin(color & bitmask)[2:]
    extracted_bits = '0' * (bitmask_len - len(extracted_bits)) + extracted_bits

    return extracted_bits

if __name__ == '__main__':
        img=Image.open("ch9.png")
        pixels = list(img.getdata())

        bits = ''

        for i in range(0, len(pixels),2):
                r = pixels[i][0]
                g = pixels[i][1]
                b = pixels[i][2]

                bits += extract_bits(r, 0x1)
                bits += extract_bits(g, 0x1)
                bits += extract_bits(b, 0x1)

                bits += '0' * (8 - len(bits) % 8)

                text = ''
                for i in range(0, len(bits), 8):
                        text += chr(int(bits[i:i+8], 2))
                print text