captcha idea: proposal for gnome outreach for women 14

List overview All Threads
Download

newer

older

The Whole Wikipedia in English...

Re: [Wikitech-l] Adding new...

Mansi Gokhale

1 Mar 2014 1 Mar '14

2:07 a.m.

hello, These are some approaches i can think of instead of a text based captcha. The image idea where users are asked to spot the odd one out like demonstrated or find all the similar images like mentioned in here<https://www.mediawiki.org/wiki/CAPTCHA> . Also a picture with a part chipped in could be shown and chipped pictures could be given as options like find the missing part from a jigsaw puzzle. The image which would be shown is http://imgur.com/uefeb08 http://imgur.com/KEJqCg3 is the picture which would be the correct option. The other options could be rotated versions of this , which would not be so easy for the bot to match. (unless it somehow worked some digital processing algorithm and matched the color gradients or something like that). This is a good option for people who do not know english or are illiterate and maybe would not understand questions like : is this a bird , plane , superman? after being shown a picture. Tell me what you think (Sorry to upload those images on imgur. i dont know how to put them on the wiki .Hope that is ok) have posted this on the CAPTCHA page<https://www.mediawiki.org/wiki/Talk:CAPTCHA>also

Show replies by date

Arthur Richards

1 Mar 1 Mar

2:25 a.m.

New subject: captcha idea: proposal for gnome outreach for women 14

I think this is an intriguing approach - particularly for use cases on mobile devices. We display captchas as necessary through MobileFrontend when they are triggered, but the mobile experience is horrible (arguably the whole captcha experience is horrible regardless of the medium, but that's another conversation). As long as we need to surface captchas, something non-text based, especially if it didn't require typing, would be preferable. On Fri, Feb 28, 2014 at 10:07 AM, Mansi Gokhale <gokhalemansi12(a)gmail.com>wrote;wrote:

...

-- Arthur Richards Software Engineer, Mobile [[User:Awjrichards]] IRC: awjr +1-415-839-6885 x6687

Brad Jorsch (Anomie)

3:29 a.m.

New subject: captcha idea: proposal for gnome outreach for women 14

On Fri, Feb 28, 2014 at 12:07 PM, Mansi Gokhale <gokhalemansi12(a)gmail.com>wrote;wrote:

...

The image idea where users are asked to spot the odd one out like demonstrated or find all the similar images like mentioned in here<https://www.mediawiki.org/wiki/CAPTCHA>

If you display 8 images and the user has to pick one, then even by random guessing the attacker has a 12.5% chance of passing the captcha. That's not good at all. Finding "all matching" is slightly better since it reduces the guessability (1/256 for 8 images), but still not very good. A traditional captcha using only A-Z is 1/308915776. To do as well with image picking, you'd need to ask the user to choose the matches from a set of about 28. Adding in numbers 2-9 is 1/1544804416, needing a set of about 31 images. The set of possible images also needs to be very large and the categorization private. https://www.mediawiki.org/wiki/Talk:Requests_for_comment/CAPTCHA#Issue:_ima… into much more detail on this issue. Then there's the issue of different interpretation. Take for example https://www.mediawiki.org/wiki/File:Find-all-captcha-idea.png. Is the second image wearing glasses? Or is that a lorgnette or something like opera glasses, both of which are held in front of the eyes rather than worn? https://www.mediawiki.org/wiki/File:Find-the-different-captcha-idea.png has a similar problem. The first image is the only one with a cigarette, and the only one with non-realistic coloring. The second is the only bald one, and the only one with something resembling a lorgnette, and the only one not looking in the general direction of the camera, and the only one with a book. The fourth is the only child. The sixth is the only obvious female (I'm not sure about the cat). The eighth is the only one smiling, and the only one with visible teeth. Also a picture with a part chipped in could be shown and chipped pictures

...

could be given as options like find the missing part from a jigsaw puzzle.

...

The image which would be shown is http://imgur.com/uefeb08 http://imgur.com/KEJqCg3 is the picture which would be the correct option. The other options could be rotated versions of this , which would not be so easy for the bot to match. (unless it somehow worked some digital processing algorithm and matched the color gradients or something like that).

That seems very simple for a computer to solve. Just find the option with minimal difference along the join edges, which is probably easier than what they already do for OCRing text captchas. As far as captchas, I still think https://xkcd.com/810/ is the way to go. -- Brad Jorsch (Anomie) Software Engineer Wikimedia Foundation

Brad Jorsch (Anomie)

3:31 a.m.

New subject: captcha idea: proposal for gnome outreach for women 14

On Fri, Feb 28, 2014 at 1:29 PM, Brad Jorsch (Anomie) <bjorsch(a)wikimedia.org

...

wrote:

...

A traditional captcha using only A-Z is 1/308915776.

That should be "a traditional *6 letter* captcha using only A-Z". Sorry for the noise. -- Brad Jorsch (Anomie) Software Engineer Wikimedia Foundation

Happy Melon

3 Mar 3 Mar

8:05 p.m.

New subject: captcha idea: proposal for gnome outreach for women 14

On 28 February 2014 18:29, Brad Jorsch (Anomie) <bjorsch(a)wikimedia.org>wrote;wrote:

...

On Fri, Feb 28, 2014 at 12:07 PM, Mansi Gokhale <gokhalemansi12(a)gmail.com

wrote:

Then there's the issue of different interpretation. Take for example https://www.mediawiki.org/wiki/File:Find-all-captcha-idea.png. Is the second image wearing glasses? Or is that a lorgnette or something like opera glasses, both of which are held in front of the eyes rather than worn? https://www.mediawiki.org/wiki/File:Find-the-different-captcha-idea.pnghas a similar problem. The first image is the only one with a cigarette, and the only one with non-realistic coloring. The second is the only bald one, and the only one with something resembling a lorgnette, and the only one not looking in the general direction of the camera, and the only one with a book. The fourth is the only child. The sixth is the only obvious female (I'm not sure about the cat). The eighth is the only one smiling, and the only one with visible teeth.

I think this is oversimplifying. Of course some people can interpret a picture puzzle in slightly different ways - the whole *point* of a captcha is to distinguish between the intuitive reasoning of a human and the formulaic reasoning of a computer; if there was absolutely no ambiguity, it would be a very poor captcha. In exactly the same way that the letters on a captcha will sometimes be distorted in such a way that humans genuinely make a mistake, sometimes the questions in a picture puzzle can be sufficiently distorted to the point that they are answered incorrectly. The 'difficulty' of *any* captcha obviously needs to be carefully calibrated to hit the sweet spot between mundanity and ambiguity. But putting out nine pictures of humans and one picture of a cat and asking for the "odd one out" is no easier to misinterpret than a squiggle that might be a G or might be a 6. --HM

Brad Jorsch (Anomie)

4 Mar 4 Mar

12:51 a.m.

New subject: captcha idea: proposal for gnome outreach for women 14

On Mon, Mar 3, 2014 at 6:05 AM, Happy Melon <happy.melon.wiki(a)gmail.com>wrote;wrote:

...

But putting out nine pictures of humans and one picture of a cat and asking for the "odd one out" is no easier to misinterpret than a squiggle that might be a G or might be a 6.

It seems to me that putting nine pictures of humans and one picture of a cat is probably not much harder of a computer vision task than trying to determine which letter a particular squiggle corresponds to, either. (And that's leaving aside the fact that an 10% success rate for random guessing seems pretty bad for a captcha.) So naturally I thought that the real captchas would have a subtler level of intended oddness, so that the possibility for unintended oddness to confuse people would be greater. -- Brad Jorsch (Anomie) Software Engineer Wikimedia Foundation

Steven Walling

3 Mar 3 Mar

11:23 p.m.

New subject: captcha idea: proposal for gnome outreach for women 14

On Fri, Feb 28, 2014 at 6:29 PM, Brad Jorsch (Anomie) <bjorsch(a)wikimedia.org

...

wrote:

...

A recent example that springs to mind with image-based CAPTCHAs (instead of text) is Snapchat's "Find the Ghost", which is very fun for users and apparently was broken very quickly.[1] A lot of times I hear people also suggest we try a honeypot on login/signup instead of text-based CAPTCHAs, and like the Snapchat example, one of the weaknesses here is just not accounting for that fact that people will target popular sites/apps directly. They'll inspect the DOM to find honeypots, they'll notice you use the same logo shape and use computer vision to find that shape, etc. However, it is not overstating it to say that the text-based CAPTCHA we use now is the single most frustrating part of creating an account or logging in (if you misremember your password, which users do all the time). To quote one of our usability tests during the last login/signup redesign: "This is ridiculous. I can't even see this.".[2] One simpler thing we might try and do right now is regenerate our current pool of CAPTCHAs to make them a bit less hard to read. We've done this kind of tweaking before without too much trouble I think?[3] 1. techcrunch.com/2014/01/21/snaptcha/ 2. https://www.mediawiki.org/wiki/Account_creation_user_experience/User_testing 3. See bug 43546 which Aaron Schulz kindly took care of. He may be able to elaborate more.

Matthew Flaschen

9:51 a.m.

I'm adding the design list. I talked about this recently with a couple of the designers. Matt Flaschen On 02/28/2014 12:07 PM, Mansi Gokhale wrote:

...

3706

days inactive

3709

days old

wikitech-l@lists.wikimedia.org

Manage subscription

7 comments

6 participants

tags (0)

participants (6)

Arthur Richards
Brad Jorsch (Anomie)
Happy Melon
Mansi Gokhale
Matthew Flaschen
Steven Walling