WackoWiki: Captcha

https://wackowiki.org/doc     Version: 17 (21.01.2023 18:07)

Captcha

1. freeCap

Author: 2005 Howard Yeend[link1], 2008 - 2023 WackoWiki Team
License: GNU General Public License


Captcha

  1. freeCap[link2]
  2. Freecap Support[link3]
  3. source:master/src/lib/captcha[link4]

1.1. Modifications

  1. Fixed: Big-endian captcha issues has been tried and tested on both little and big endian systems. Now auto-works on both.
  2. Fixed: Big Endian issues with captcha system. Added a test which attempts to auto-detect the systems big-endian status. Needs testing on a big-endian system.

1.2. freeCapsettings settings

1.2.1. How can I make the image more readable?

freeCap is designed to be as customisable as possible. There are several variables you can change to make the text more readable:
  1. Change the bg_type to 0, 1 or 2
  2. Reduce the chunk factor
  3. Use more readable fonts
  4. Alter the fade factor

But bear in mind that increased human readability means decreased OCR-resistance. On the other hand, a CAPTCHA is more often simply a deterrent and the actual theoretical security matters little.

1.2.2. What can you do about accessibility issues?

Nothing, my suggestion for accessibility is to allow people to enter their details without passing the CAPTCHA, but send non-captcha’ed submittals to a ‘pending’ queue for manual review. It’s a much much simpler solution that still leaves the site accessible.

1.3. WackoWiki related settings

'captcha_new_comment' => 1,
'captcha_new_page' => 1,
'captcha_edit_page' => 1,
'captcha_registration' => 1,

2. How to solve your freeCap problem

2.1. Where are the fonts/images?

For security, they begin with a '.', which means that Apache won’t allow people to view them directly. Unfortunately, Windows also sees files beginning with a dot as hidden. Make sure that you’re set up to see hidden files in windows explorer (your file browser); go to the ‘Tools’ menu, then ‘Folder Options’, click the ‘View’ tab and make sure “Show hidden files and folders” has a check mark next to it. Press OK and you should see all the fonts and images appear on your local machine – now you can upload them.

2.2. All I get is a blank image, or I get an error about "fopen(./.ht_freecap_font1.gdf):"

Make sure that you have uploaded the fonts (see above), and the dictionary file.

If you have, try changing freecap’s config to use a randomly generated CAPTCHA; if it works after that, make sure the permissions on .ht_freecap_words are set to 700.

2.3. What does ‘service no longer available’ mean?

freeCap has built-in brute force detection; this message is shown once a user has tried more than a reasonable amount of times to enter the text. As with almost all freeCap features, this is user-definable; to disable this feature, set $max_attempts to something massive like 999999999999999.
A future version will provide a less hacky way of disabling this feature.

2.4. any – Fatal error: Call to undefined function: imagecreate() or image_anything()

You must have GD installed in order to use freeCap.