MyBB Community Forums

I'm currently working on a plugin that modifies the original MyBB captcha. Instead of characters, it will display images which you have to recognize. The images can be anything you want. Currently I'm developing with two very crappy image sets, shapes (square circle star) and animals (cat dog horse human). The plugin randomly choses one of the available image sets, then chooses random images out of this set, and renders those onto the captcha.

I call it the ImaCaptcha plugin, short for Image Captcha, I'm a Captcha (plugin), or Imad Jomaa Captcha, whatever you like best (actually I made the last one up ).

Currently it looks like this:

[attachment=17812] (solution: cat human dog horse)
[attachment=17813] (solution: star circle square star)

I know it looks crappy, but this is less than 6 hours into the development process. Users will have the ability to add their own image sets, so you can make something that is somehow related to the theme of your forum, such as game characters or country flags or whatever.

It will be available under GPL and the current state is already publicly available here:

http://github.com/frostschutz/ImaCaptcha

So far it can only render the image, but doesn't actually validate it (although the hooks to do so are already in place). So it's not usable quite yet. I expect to finish this plugin in the next couple of days.

That seams to be tricky if a user doesn't know how to name the images.

Forget tricky. If the user doesn't know how to name the images, he can't solve it. End of story.

That's why you have to use better images than the crappy ones I'm currently using (for development and testing purposes), and the original captcha description ("Please enter the text contained within the image on the right in to the text box below it.") has to be changed to explain to the user what exactly it is he has to do.

Point being, while it's obvious that no one can recognize a cat or dog when it's yours truly doodling in Inkscape for <10 seconds, it's not impossible to make images that anyone can recognize at first glance. So I don't see it as a problem, it's a question of how good the image set is.

Maybe this one is more to your liking?

[attachment=17814] (solution: mac windows linux mac)

Also, an image can have more than one possible solution. So if you put apple instead of mac, or pc instead of windows, or tux instead of linux, it's still valid. If you want to keep it short, you could also translate it to mwlm.

Sounds interesting, but not something I would use. That would most likely decrease registrations. Might be easier for some, but harder for others. So if they can't enter the damn captcha they instantly leave the site.

And this would require a few side notes next to the captcha, because 99% of users aren't used to this kind of captcha.

This is certainly an interesting concept, but I think it will be difficult to make it terribly practical.
Obviously, the images are going to require some sort of warping or distortion to fool bots, but most images tend to have a higher level of detail than text, so the manipulations you can perform on them are more limited.
With letters and numbers, users are limited to 36 different characters. If there's a character a user can't readily determine, they can try to match it to one of the 36 characters. With images, there's really an infinite set of possibilities as far as the user is concerned.
As also mentioned, there's the issue of unfamiliarity. Also does require multiple words defined for each image (or some interesting thesaurus attached), and furthermore, for each language. Which would most likely lead to webmasters just using a standard set of some sorts rather than customising their own set of images, and thus, probably won't be that much more effective than standard Capchas.
Choice of images may be limited as well, for example, not everyone recognises the Linux mascot in your above example. (also, I didn't recognise the last image in that sequence)

But still, it's an interesting concept.

Regarding bots, I'm naturally assuming that letter-captchas are more interesting to them, as they can use simple OCR to solve them. With this captcha, if you make your own set of images, the captcha will be custom to your forum and not used anywhere else. So a bot would have to be custom made for your forum specifically.

Bots are also the reason why I started this project... in our forum guests are allowed to post and we had at least one case where a bot managed to post spam despite the captcha being enabled.

The letters in the standard captcha are sometimes easy to confuse (l I 1). It also sometimes rotates the letters into each other. Our users complained a lot about it. That's why I already modified it to use upper case letters only, which made it easier for the users, but most likely also easier for the bots. The standard captcha also allows an unlimited number of tries and it produces an unlimited number of different images for one and the same solution. Solving it should be an easy task for a machine.

For this plugin, I have a very specific image set in mind for my forum, which goes well with the forums theme, so I'm hoping that the users will actually like it. We'll see. I'm very well aware that this is an experiment that may just as well go wrong - if my users don't accept it and I can't improve the issues they have with it, I won't use it myself. But that's something I can only find out if I make it first...

(2010-04-05, 11:21 AM)frostschutz Wrote: [ -> ]Regarding bots, I'm naturally assuming that letter-captchas are more interesting to them, as they can use simple OCR to solve them. With this captcha, if you make your own set of images, the captcha will be custom to your forum and not used anywhere else. So a bot would have to be custom made for your forum specifically.

The problem is, would anyone really customize their images?

(2010-04-05, 11:21 AM)frostschutz Wrote: [ -> ]Bots are also the reason why I started this project... in our forum guests are allowed to post and we had at least one case where a bot managed to post spam despite the captcha being enabled.

Systems like reCAPTCHA are generally fairly effective. But it depends on what level the bot is operating at.
Systems like Decaptcher aren't going to be fooled whatever image type system you use, as it uses humans (my guess is slavery in 3rd world countries or similar) to solve the captchas.

(2010-04-05, 11:21 AM)frostschutz Wrote: [ -> ]The standard captcha also allows an unlimited number of tries

That wouldn't exactly be the issue with the captcha itself, more on what's implementing it.

(2010-04-05, 11:21 AM)frostschutz Wrote: [ -> ]it produces an unlimited number of different images for one and the same solution. Solving it should be an easy task for a machine.

Don't quite follow the chain of logic there >_>

(2010-04-05, 11:21 AM)frostschutz Wrote: [ -> ]For this plugin, I have a very specific image set in mind for my forum, which goes well with the forums theme, so I'm hoping that the users will actually like it. We'll see. I'm very well aware that this is an experiment that may just as well go wrong - if my users don't accept it and I can't improve the issues they have with it, I won't use it myself. But that's something I can only find out if I make it first...

Am interested in this myself. After all, my assumptions are, really, just assumptions...

Why dont you have a key of about 10 images, and have this help the user. But instead of writing it in you have to click on a link, powered by java or such. And only the correct sequence works. However the key doesnt assign letters it assigns a numbe rto the image. There is then a coloured line that connects the image to the number. This would fool bots and such.

(2010-04-05, 12:08 PM)Yumi Wrote: [ -> ]The problem is, would anyone really customize their images?

I don't care about what anyone does with this plugin. I won't ship the plugin with images anyway. That's not within my ability - I'm a programmer, not a graphics designer. And I don't want to include images that are not made by me. So people who want to use this, would be either forced to make their own, or depend on others who share their image sets, or pick up free images on the net from openclipart.org or whereever.

(2010-04-05, 12:08 PM)Yumi Wrote: [ -> ]Systems like Decaptcher aren't going to be fooled whatever image type system you use, as it uses humans (my guess is slavery in 3rd world countries or similar) to solve the captchas.

Decaptcher is actually a good example. I reloaded their captcha.php lots of times but all it ever displays is letters. If it displays only the image without explanation, the human won't necessarily know what to do, because the context is missing...

@tommykent1210,
Yes, you can do that with this plugin, if it makes you happy. Except you'd still have to type the numbers instead of click.

This is WAY too complicated. If a website had a Captcha like this, I'd leave. The last example would of stumped me a year or so ago. I didn't know who Tux was or what he stood for.

I guess this would be good for Forums with an older user base. I'd definitely wouldn't want to use it on a site that's attracting all ages to join.