puremango.co.uk

How to solve your freeCap problem

First of all, make sure you’re using the latest version.

Second, read the common problems below

Third, write a comment here. I’m pretty rubbish at responding, especially given that this software is four years old now, but you can hope.

Fourth, if it’s really urgent you can get my undivided attention by donating some paypal funds and asking your support question in the comments box.

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Many thanks to everyone who has contributed fixes and tips :-)

Common Problems

1.4.1 – The image doesn’t display, or
1.4.1 – There are NOTICE errors displayed
add the following line to the top of all php files:
error_reporting(E_ALL ^ E_NOTICE);
This will be fixed in the next version

How do I integrate freeCap with xyz application?
See the main PHP CAPTCHA page – there are plugins for mambo/joomla, plugins for phpBB, a wiki with CAPTCHA, a blog with CAPTCHA and other implementations of freecap linked there. If it’s not listed then roll up your sleeves and get coding :)

Where are the installation instructions?
There are none. A future version may include examples and instructions. For the moment, some experience with PHP is required, but see the question about getting it to send email, below.

1.4.1 – How do I get it to send email?, or
1.4.1 – In the filename I put in the Header line, how do I access the submitted data
At the moment, it’s just a CAPTCHA script; i.e. it won’t fully integrate with your existing form without a little work on your part.
A future version will include several example scripts, but for the moment, on about line 54, where it says
// now process form
just put
include("xxx.php");
exit();
where xxx.php is the file that your old form used to submit to, eg mail.php

1.4.1 – 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. (thanks to David for that tip)

Some FTP clients, including Dreamweaver’s, don’t ‘see’ files beginning with ‘.’ – try a different FTP client (like coreFTP, fireFTP). You should be able to see “.ht_freecap_font1.gdf”, “.ht_freecap_font2.gdf” and so on in your freecap directory.

1.4.1 – All I get is a blank image, or
1.4.1 – 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.
If it still doesn’t work, see the answer below, and if that doesn’t apply, contact me.

1.4.1 – All I get is a blank image – part two
If you’re not using an intel processor (in other words your server is not Linux or Windows, it is mac, sparc, aix, motorola, etc), then I’m afraid this is a bastard problem from hell for which I have no fix yet.

GD fonts are architecture-dependant, which means that for your big-endian processors I need to produce special font files.
Try to get hold of some big-endian GD fonts and *PLEASE* let me know if you find some. I’m sorry but I don’t have the resources to fix this. If you manage to get freeCap working on your processor please let me know so I can publish your findings and help other big-endians.
The only workaround I can suggest is to either:
-find big-endian GD fonts
-hex edit the included fonts and send me copies
-use an older version of freeCap that didn’t use GD fonts and hack in the security updates from earlier versions (bad idea)
-use a different CAPTCHA system :-(

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.

any – Fatal error: Call to undefined function: imagecreate() or image_anything()
You must have GD installed in order to use freeCap.

1.4 – The image never changes
Upgrade to 1.4.1, or upgrade your PHP version.
This is because older PHP versions do not initialise the Random Number Generator automatically.

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:
-Change the bg_type to 0, 1 or 2
-Reduce the chunk factor
-Use more readable fonts
-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.

What can you do about accessibility issues?
Nothing, but see below.

Is there an audio CAPTCHA?
No. Firstly, it’d be bloody hard to code in PHP. Secondly, it’s bloody hard to make it secure – see this eye-opening page about cracking voice captcha for more info.

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.

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Add your questions below. I will not respond via email, so check back here for a response, or email me for an email response.

Once resolved, I remove comments from here – if your comment is gone, it’s been resolved – look above. Thanks for contributing.

Please only add support questions here. For general comments, use this page.

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• Breaking CAPTCHA without OCR
• free PHP CAPTCHA v1.4.1
• Free PHP Scripts / Web Projects