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Tim Starling df4806c64c Improve FancyCaptcha resistance to OCR
Tesseract is a popular open source OCR package. Running it on
FancyCaptcha images, with no training or configuration, yielded a 56%
break rate. By restricting the character set, the OCR break rate was
improved to 66%.

So:
* Reduce k, increase wob scale, increase rr fuzz. The net effect of
  these three changes is to more reliably bend the baseline. In the old
  captcha, the baseline would often be bent by chance, but when it
  wasn't bent, it provided a very easy challenge for the OCR engine.
  This reduced the break rate from 66% to around 40%.
* Introduce additive noise, based on a bilinear upscale of a random
  greyscale image. This, combined with the above change, reduces the
  Tesseract break rate to 6%.

Change-Id: I05b5bb6475de9378cd89cce13b1b2f28b32cd405
2014-09-26 08:47:55 +10:00
i18n Localisation updates from https://translatewiki.net. 2014-09-22 21:43:40 +02:00
maintenance Merge "Disable ulimit time limit for long-running captcha.py script." 2013-01-02 18:27:41 +00:00
resources Get Asirra captcha working on more forms 2013-06-11 12:59:13 -07:00
.gitignore Maintenance for ConfirmEdit extension. 2012-08-16 23:21:50 +02:00
.gitreview Adding .gitreview 2012-03-23 10:18:11 -07:00
ApiFancyCaptchaReload.php ApiFancyCaptchaReload: Replace use of PHP shorttag 2013-06-28 16:18:10 -07:00
Asirra.class.php Use protocol-relative link for Asirra script. 2013-05-03 15:45:38 -04:00
Asirra.i18n.php Update i18n shim 2014-04-22 13:15:23 +00:00
Asirra.php Migrate to JSON i18n 2014-03-26 12:58:25 +01:00
blacklist Add more words to blacklist 2014-06-24 11:02:04 -07:00
Captcha.php Make captchas use mw-ui-input when available 2014-07-29 18:40:56 -07:00
captcha.py Improve FancyCaptcha resistance to OCR 2014-09-26 08:47:55 +10:00
CaptchaStore.php (bug 37643) Ensure a session is created when necessary for Captcha 2012-09-28 00:37:03 +00:00
ConfirmEdit.alias.php Localisation updates from https://translatewiki.net. 2014-04-10 20:28:59 +00:00
ConfirmEdit.i18n.php Update i18n shim 2014-04-22 13:15:23 +00:00
ConfirmEdit.php Migrate to JSON i18n 2014-03-26 12:58:25 +01:00
ConfirmEditHooks.php Remove unused/incomplete stale HTMLCaptchaField 2014-02-18 02:13:12 +00:00
COPYING Add COPYING 2014-02-08 01:51:17 +00:00
FancyCaptcha.class.php Make captchas use mw-ui-input when available 2014-07-29 18:40:56 -07:00
FancyCaptcha.i18n.php Update i18n shim 2014-04-22 13:15:23 +00:00
FancyCaptcha.php Migrate to JSON i18n 2014-03-26 12:58:25 +01:00
MathCaptcha.class.php Use PHP's built-in class_exists instead of MWInit::classExists 2013-07-24 01:00:28 -07:00
MathCaptcha.php More maintenance for ConfirmEdit extension. 2012-09-02 14:26:45 +02:00
QuestyCaptcha.class.php Make captchas use mw-ui-input when available 2014-07-29 18:40:56 -07:00
QuestyCaptcha.i18n.php Update i18n shim 2014-04-22 13:15:23 +00:00
QuestyCaptcha.php Migrate to JSON i18n 2014-03-26 12:58:25 +01:00
README Update call to MathRenderer due to changes to Math extension. 2013-04-18 00:08:52 -07:00
ReCaptcha.class.php Update API parameter injection 2013-03-16 11:51:25 -04:00
ReCaptcha.i18n.php Update i18n shim 2014-04-22 13:15:23 +00:00
ReCaptcha.php Migrate to JSON i18n 2014-03-26 12:58:25 +01:00
recaptchalib.php Use public instead of var in classes 2014-08-17 22:04:49 +01:00

ConfirmEdit extension for MediaWiki

This extension provides various CAPTCHA tools for MediaWiki, to allow
for protection against spambots and other automated tools.

For more information, see the extension homepage at:
http://www.mediawiki.org/wiki/Extension:ConfirmEdit

== Overview ==

The following modules are included in ConfirmEdit:

* SimpleCaptcha - users have to solve an arithmetic math problem
* MathCaptcha - users have to solve a math problem that's displayed as
an image
* FancyCaptcha - users have to identify a series of characters, displayed
in a stylized way
* QuestyCaptcha - users have to answer a question, out of a series of
questions defined by the administrator(s)
* ReCaptcha - users have to identify a series of characters, either
visually or audially, from a widget provided by the reCAPTCHA service
* Asirra - users have to identify the cats in a set of photos of cats
and dogs, from a widget provided by the Microsoft Asirra service

== License ==

ConfirmEdit is published under the GPL license.

== Authors ==

The main framework, and the SimpleCaptcha and FancyCaptcha modules, were
written by Brion Vibber.

The MathCaptcha module was written by Rob Church.

The QuestyCaptcha module was written by Benjamin Lees.

The reCAPTCHA module was written by Mike Crawford and Ben Maurer.

The Asirra module was written by Bachsau.

Additional maintenance work was done by Yaron Koren.

== Changelog ==

= Version 1.2
Fixes bug 46132 - ConfirmEdit fatal error when using MathCaptcha and current Math extension.
See <https://bugzilla.wikimedia.org/show_bug.cgi?id=46132>.