Steganography - Python

from PIL import image
import binascii
import optparse

def rgb2hex(r,g,b):
    return '#{:02x}{:02x}{:02x}'.format(r,g,b)

def hex2rgb(hexcode):
    return tuple(map(ord,hexcode[1:],decode('hex')))

def str2bin(message):
    binary=bin(int(binascii.hexify(message),16))
    return binary[2:]

def binary2str(binary):
    message=binascii.unhexify('%x' % (int('0b'+binary,2)))
    return message

def encode(hexcode,digit):
    if hexcode[-1] in ('0','1','2','3','4','5'):
        hexcode=hexcode[:-1]+digit
        return hexcode
    else:
        return None

def decode(hexcode):
    if hexcode[-1] in ('0','1'):
        return hexcode[-1]
    else:
        None

def hide(filename, message):
    img=Image.open(filename)
    binary=str2bin(message)+'1111111111111110'
    if img.mode in ('RGBA'):
        img=img.convert('RGBA')
        datas=image.getdata()
        newData=[]
        digit=0
        temp=''
        for item in datas:
            if (digit<len(binary)):
                newpix=encode(rgb2hex(item[0],item[1],item[2]),binayu[digit])
                if newpix==None:
                    newData.append(item)
                else:
                    r,g,b=hex2rgb(newpix)
                    newData.append((r,g,b,255))
                    digit+=1
            else:
                newData.append(item)
        img.putdata(newData)
        img.save(filename,"PNG")
        return "Completed!"
    return "Incorrect Image Mode!!"

def retrieve(filename):
    img=Image.open(filename)
    binary=''

    if img.mode in ('RGBA'):
        img=img.convert('RGBA')
        datas=img.getdata()

        for item in datas:
            digit=decode(rgb2hex(item[0],item[1],item[2]))
            if digit==None:
                pass
            else:
                binary=binary+digit
                if(binary[-16:]=="1111111111111110"):
                    print "Success"
                    return bin2str(binary[:-16])
        return bin2str(binary)
    return "Incorrect Image Mode!!"

def Main():
    parser=optparse.OptionParser('Usage: %prog '+'-e/d <target file>')
    parser.add_option('-e',dest='hide',type="string",help="target picture path to hide text")
    parser.add_option('-d',dest='retrieve',type="string",help="target picture path to retrieve text")
    (options.args)=parser.parse.args()
    if (options.hide != None):
        text=raw_input('Enter message:')
        print hide(options.hide,text)
    elif (options.retreive != None):
        print retrieve(options.retrieve)
    else:
        print parser.usage
        exit(0)

if __name__=="__main__":
    Main()