Captchas and Human Readability - Discussion

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Discuss features as they are added to the new version. Give us your feedback. Don't post bug reports, feature requests, support questions or suggestions here. Feature requests are closed.
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Francesc Lynx
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Re: Captchas and Human Readability - Discussion

Post by Francesc Lynx »

Highway of Life wrote: For example, Spanish: El Gato, well, what's do spanish use for the English equivilant of "meow"?

Well, we use "miau" :lol:

I think the question is a good idea, but not as a substitute of CAPTCHAs. Maybe a capable admin could think some questions, and use this method instead of CAPTCHAs, but the "default admin" would use the regular CAPTCHAs.
"Since the dawn of time... [insert amazing event]"
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Eelke
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Re: Captchas and Human Readability - Discussion

Post by Eelke »

I think the question is a good idea, but not as a substitute of CAPTCHAs.

Correct me if I'm wrong, but I think the word CAPTCHA doesn't imply anything about the kind of test, it just means "test to distinguish computers from humans" (Completely Automated Public Turing test to tell Computers and Humans Apart)*. It's become almost equivalent with the visual confirmation graphics with onfuscated characters, but I think technically two radio buttons with the labels "Yes" and "No" and the question "Are you human?" would qualify as a CAPTCHA (albeit not a very good one, especially if it would be a standard question for all phpBB boards).

All I'm trying to say is, the proposed system with questions is as much a CAPTCHA as the visual tests are. This thread may get confusing if we're going to use the term CAPTCHA for different things.

*: Actually, this is what Wikipedia has to say on the Turing Test: "The Turing test is a proposal for a test of a machine's capability to perform human-like conversation." So technically, all stuff we've discussed thusfar, and what is generally called CAPTCHA, isn't a CAPCHA at all ;)
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-=ET=-
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Re: Captchas and Human Readability

Post by -=ET=- »

Nylith wrote: This has nothing to do with Captchas, since this is just an alternative input method - sending the data over POST (as a bot would do) avoids it.

Not sure.
As you need to press a button, the number you have pressed can be send immediately to the server and not stored in any hidden or displayed field (the field with the black dots is just there to display how many numbers the user has enter - nothing else). This mean that it will be much more difficult for a bot to do the same, especially if you use other technique to change the variable name at each display of the page :?
To look a little bit closer I think... :)
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phoenix-cms
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Re: Captchas and Human Readability

Post by phoenix-cms »

well i dont post much around here as i busy working on a opensource cms that intergrates with phpbb3 but i must say guys mainly who ever done the capture its changed alot and i like the way your using a similar way for capture as hn_capture class and there seems to be no trouble in english to read the charactors at all, even the non gd version still looks great
good job guys and thanks for all the work your doing and i support opensource all the way becuase when you are done the community can start getting involved

Steve :)
working on a cms to be intergrated with phpbb 3 without any major code changing to keep with phpbb 3 guidelines
Dark_Génova
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Re: Captchas and Human Readability

Post by Dark_Génova »

This new captcha is really hard to read for human. I think administrators will disabled this tool, if you dont change it a little :/
phoenix-cms
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Re: Captchas and Human Readability

Post by phoenix-cms »

how so? explain please as it seems perfect to me and just like hn_capture but alot lighter :D

like the old code was really heavy and even decided to take sometime to render and causing a bit of high memory usage for a few seconds but now its fine to me

Steve :)
working on a cms to be intergrated with phpbb 3 without any major code changing to keep with phpbb 3 guidelines
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EXreaction
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Re: Captchas and Human Readability

Post by EXreaction »

Dark_Génova wrote: This new captcha is really hard to read for human. I think administrators will disabled this tool, if you dont change it a little :/


Do you mean the newest one they just put in a few days ago?

It looks ok to me...but I won't use it.
Dark_Génova
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Re: Captchas and Human Readability

Post by Dark_Génova »

I mean the captcha where you have some lines / rectangles, and you need to write the code on the right who match the icon on the left. It's a really good idea, but the backgrounds colors are so deep and its really difficult to read correctly the code and to identify wich icon is matching on the left. I refresh the page several time, and the captcha was always unreadable.

I think if you want to do a perfect captcha, just do some various tools. For example a "writing captcha" with some questions / answer the administrator can change, a "mathematic captcha" width a gd image who have some calcul (write the result of 14 + 176 - 13), a "classic captcha". Dont use this geometric new captcha please, or light a little more the background color please ^^

Thanks, @+
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EXreaction
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Re: Captchas and Human Readability

Post by EXreaction »

They removed all of those extra captchas and replaced it with a single version. ;)
dave_t
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Re: Captchas and Human Readability

Post by dave_t »

Hi, well i'm entirely new to this forum, and I only recently learned what a captcha actually was. I admin a phpbb site and we've seen an influx in people (i assume bots) creating profiles linking to unwholesome sites.

I'd say that captchas need to be relatively simple, otherwise many users simply won't understand them. I wasn't even 100% sure I was entering the correct code when signing up for this forum.

From what I've read, it looks like at least one (and probably more) captcha-beating algorithms work by identifying egdes of character shapes using an edge detection algorithm. Then once they have the shapes (and also the order), it just takes a well-trained neural net to decipher any amount of distortion/rotation (effectively mirroring the process of humans learning to read). So my suggestion would be to make the edges harder to detect.

One intriguing option I saw here was to use an image (presumably the user identifies the 'elephant' and types the word). Unfortunately, I don't think it would be too hard to beat, once the stock of images was known. Plus it relies on language, spelling competency, etc.

So anyway, what about if a random image (e.g. from images.google.com) was used to seed the distortion of the text?

I made this one using a simple sequence in GIMP, using a feathered selection of the text which I then used to invert the original image. The feathering should beat the edge detection, and I'd be very surprised if someone could write a reliable algorithm to beat it. The only problem is to make sure that there isn't too much 50% grey in the image, since this inverts back to grey. I think a suitable image selection algorithm wouldn't be too hard to write.

Image

Just thowing this into the melting pot, hoping it inspires someone....

Dave
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