#!/usr/bin/python3 # # Script to generate distorted text images for a captcha system. # # Copyright (C) 2005 Neil Harris # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License along # with this program; if not, write to the Free Software Foundation, Inc., # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. # http://www.gnu.org/copyleft/gpl.html # # Further tweaks by Brion Vibber : # 2006-01-26: Add command-line options for the various parameters # 2007-02-19: Add --dirs param for hash subdirectory splits # Tweaks by Greg Sabino Mullane : # 2008-01-06: Add regex check to skip words containing other than a-z import random import math import hashlib from optparse import OptionParser import os import sys import re import multiprocessing import time try: from PIL import Image from PIL import ImageFont from PIL import ImageDraw from PIL import ImageEnhance from PIL import ImageOps from PIL import ImageMath except: sys.exit("This script requires the Python Imaging Library - http://www.pythonware.com/products/pil/") nonalpha = re.compile('[^a-z]') # regex to test for suitability of words # Pillow 9.2 added getbbox to replace getsize, and getsize() was removed in Pillow 10 # https://pillow.readthedocs.io/en/stable/releasenotes/10.0.0.html#font-size-and-offset-methods # We don't have a requirements.txt, and therefore don't declare any specific supported or min version... IMAGEFONT_HAS_GETBBOX = hasattr(ImageFont.ImageFont, "getbbox") # Does X-axis wobbly copy, sandwiched between two rotates def wobbly_copy(src, wob, col, scale, ang): x, y = src.size f = random.uniform(4*scale, 5*scale) p = random.uniform(0, math.pi*2) rr = ang+random.uniform(-10, 10) # vary, but not too much int_d = Image.new('RGB', src.size, 0) # a black rectangle rot = src.rotate(rr, Image.BILINEAR) # Do a cheap bounding-box op here to try to limit work below bbx = rot.getbbox() if bbx == None: return src else: l, t, r, b= bbx # and only do lines with content on for i in range(t, b+1): # Drop a scan line in xoff = int(math.sin(p+(i*f/y))*wob) xoff += int(random.uniform(-wob*0.5, wob*0.5)) int_d.paste(rot.crop((0, i, x, i+1)), (xoff, i)) # try to stop blurring from building up int_d = int_d.rotate(-rr, Image.BILINEAR) enh = ImageEnhance.Sharpness(int_d) return enh.enhance(2) def gen_captcha(text, fontname, fontsize, file_name): """Generate a captcha image""" # white text on a black background bgcolor = 0x0 fgcolor = 0xffffff # create a font object font = ImageFont.truetype(fontname,fontsize) # determine dimensions of the text if IMAGEFONT_HAS_GETBBOX: dim = font.getbbox(text)[2:] else: dim = font.getsize(text) # create a new image significantly larger that the text edge = max(dim[0], dim[1]) + 2*min(dim[0], dim[1]) im = Image.new('RGB', (edge, edge), bgcolor) d = ImageDraw.Draw(im) x, y = im.size # add the text to the image d.text((x/2-dim[0]/2, y/2-dim[1]/2), text, font=font, fill=fgcolor) k = 2 wob = 0.09*dim[1] rot = 45 # Apply lots of small stirring operations, rather than a few large ones # in order to get some uniformity of treatment, whilst # maintaining randomness for i in range(k): im = wobbly_copy(im, wob, bgcolor, i*2+3, rot+0) im = wobbly_copy(im, wob, bgcolor, i*2+1, rot+45) im = wobbly_copy(im, wob, bgcolor, i*2+2, rot+90) rot += 30 # now get the bounding box of the nonzero parts of the image bbox = im.getbbox() bord = min(dim[0], dim[1])/4 # a bit of a border im = im.crop((bbox[0]-bord, bbox[1]-bord, bbox[2]+bord, bbox[3]+bord)) # Create noise nblock = 4 nsize = (im.size[0] // nblock, im.size[1] // nblock) noise = Image.new('L', nsize, bgcolor) data = noise.load() for x in range(nsize[0]): for y in range(nsize[1]): r = random.randint(0, 65) gradient = 70 * x // nsize[0] data[x, y] = r + gradient # Turn speckles into blobs noise = noise.resize(im.size, Image.BILINEAR) # Add to the image im = ImageMath.eval('convert(convert(a, "L") / 3 + b, "RGB")', a=im, b=noise) # and turn into black on white im = ImageOps.invert(im) # save the image, in format determined from filename im.save(file_name) def gen_subdir(basedir, md5hash, levels): """Generate a subdirectory path out of the first _levels_ characters of _hash_, and ensure the directories exist under _basedir_.""" subdir = None for i in range(0, levels): char = md5hash[i] if subdir: subdir = os.path.join(subdir, char) else: subdir = char fulldir = os.path.join(basedir, subdir) if not os.path.exists(fulldir): os.mkdir(fulldir) return subdir def try_pick_word(words, badwordlist, verbose, nwords, min_length, max_length): if words is not None: word = words[random.randint(0,len(words)-1)] while nwords > 1: word2 = words[random.randint(0,len(words)-1)] word = word + word2 nwords = nwords - 1 else: word = '' max_length = max_length if max_length > 0 else 10 for i in range(0, random.randint(min_length, max_length)): word = word + chr(97 + random.randint(0,25)) if verbose: print("word is %s" % word) if len(word) < min_length: if verbose: print("skipping word pair '%s' because it has fewer than %d characters" % (word, min_length)) return None if max_length > 0 and len(word) > max_length: if verbose: print("skipping word pair '%s' because it has more than %d characters" % (word, max_length)) return None if nonalpha.search(word): if verbose: print("skipping word pair '%s' because it contains non-alphabetic characters" % word) return None for naughty in badwordlist: if naughty in word: if verbose: print("skipping word pair '%s' because it contains word '%s'" % (word, naughty)) return None return word def pick_word(words, badwordlist, verbose, nwords, min_length, max_length): for x in range(1000): # If we can't find a valid combination in 1000 tries, just give up word = try_pick_word(words, badwordlist, verbose, nwords, min_length, max_length) if word: return word sys.exit("Unable to find valid word combinations") def read_wordlist(filename): if not os.path.isfile(filename): return [] f = open(filename) words = [x.strip().lower() for x in f.readlines()] f.close() return words def run_in_thread(object): count = object[0] words = object[1] badwordlist = object[2] opts = object[3] font = object[4] fontsize = object[5] for i in range(count): word = pick_word(words, badwordlist, verbose, opts.number_words, opts.min_length, opts.max_length) salt = "%08x" % random.randrange(2**32) # 64 bits of hash is plenty for this purpose md5hash = hashlib.md5((key+salt+word+key+salt).encode('utf-8')).hexdigest()[:16] filename = "image_%s_%s.png" % (salt, md5hash) if opts.dirs: subdir = gen_subdir(opts.output, md5hash, dirs) filename = os.path.join(subdir, filename) if opts.verbose: print(filename) gen_captcha(word, font, fontsize, os.path.join(opts.output, filename)) if __name__ == '__main__': """This grabs random words from the dictionary 'words' (one word per line) and generates a captcha image for each one, with a keyed salted hash of the correct answer in the filename. To check a reply, hash it in the same way with the same salt and secret key, then compare with the hash value given. """ script_dir = os.path.dirname(os.path.realpath(__file__)) parser = OptionParser() parser.add_option("--wordlist", help="A list of words (required)", metavar="WORDS.txt") parser.add_option("--random", help="Use random characters instead of a wordlist", action="store_true") parser.add_option("--key", help="The passphrase set as $wgCaptchaSecret (required)", metavar="KEY") parser.add_option("--output", help="The directory to put the images in - $wgCaptchaDirectory (required)", metavar="DIR") parser.add_option("--font", help="The font to use (required)", metavar="FONT.ttf") parser.add_option("--font-size", help="The font size (default 40)", metavar="N", type='int', default=40) parser.add_option("--count", help="The maximum number of images to make (default 20)", metavar="N", type='int', default=20) parser.add_option("--badwordlist", help="A list of words that should not be used", metavar="FILE", default=os.path.join(script_dir, "badwordlist")) parser.add_option("--blacklist", help="DEPRECATED: list of words that should not be used", metavar="FILE", default=os.path.join(script_dir, "blacklist")) parser.add_option("--fill", help="Fill the output directory to contain N files, overrides count, cannot be used with --dirs", metavar="N", type='int') parser.add_option("--dirs", help="Put the images into subdirectories N levels deep - $wgCaptchaDirectoryLevels", metavar="N", type='int') parser.add_option("--verbose", "-v", help="Show debugging information", action='store_true') parser.add_option("--number-words", help="Number of words from the wordlist which make a captcha challenge (default 2)", type='int', default=2) parser.add_option("--min-length", help="Minimum length for a captcha challenge", type='int', default=1) parser.add_option("--max-length", help="Maximum length for a captcha challenge", type='int', default=-1) parser.add_option("--threads", help="Maximum number of threads to be used to generate captchas.", type='int', default=1) opts, args = parser.parse_args() if opts.wordlist: wordlist = opts.wordlist elif opts.random: wordlist = None else: sys.exit("Need to specify a wordlist") if opts.key: key = opts.key else: sys.exit("Need to specify a key") if opts.output: output = opts.output else: sys.exit("Need to specify an output directory") if opts.font and os.path.exists(opts.font): font = opts.font else: sys.exit("Need to specify the location of a font") badwordlist = read_wordlist(opts.blacklist) + read_wordlist(opts.badwordlist) count = opts.count fill = opts.fill fontsize = opts.font_size threads = opts.threads if fill: count = max(0, fill - len(os.listdir(output))) words = None if wordlist: words = read_wordlist(wordlist) words = [x for x in words if len(x) in (4,5) and x[0] != "f" and x[0] != x[1] and x[-1] != x[-2]] if count == 0: sys.exit("No need to generate CAPTCHA images.") if count < threads: chunks = 1 threads = 1 else: chunks = (count // threads) p = multiprocessing.Pool(threads) data = [] print("Generating %s CAPTCHA images separated in %s image(s) per chunk run by %s threads..." % (count, chunks, threads)) for i in range(0, threads): data.append([chunks, words, badwordlist, opts, font, fontsize]) p.map(run_in_thread, data)