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March 1, 2005 12:39 AM

Broken: Challenge response text

Olivier Wiener found this problem on a Swiss search engine. (Challenge-response text cuts off the last character on the right edge of the graphic.)


Actually, those visual challenge-response systems are intrinsically broken. They don't do what they claim, which is to prove the user is human; what they prove is that the user is a human with good eyesight and no visual processing problems such as dyslexia. I often have to enter those things several times because I unknowingly transpose digits in them...

Posted by: codeman38 at March 1, 2005 02:48 AM

I agree, challenge response systems are completly broken. Forget using the system if you're visually impaired. Not only that but they are designed to limit usage of systems by scripts, but if they just analyzed their log files and found out that a handful of sites were causing the majority of load, they could blacklist those sites and make it easier on the rest of us.

A very broken solution, to a problem that doesn't exist.

Posted by: Joshua Wood at March 1, 2005 10:27 AM

Forget vision problems. There's some sites out there that warp, obfuscate and noise up the letters so completely that I make errors with normal vision. There was one that compressed the top of a lower case h so it looked just like a lower case n.

Posted by: Citizen Of Trantor at March 1, 2005 11:30 AM

I completely agree. There have been some sites where the letters have been warped so severely it has taken me mulitple attempts just to figure out what they are. Very Frustrating.

Posted by: Daizee at March 1, 2005 11:40 AM

Looking at the actual text pattern in the image, doesn't look too hard for software to detect the text in that one...

Posted by: Reed at March 1, 2005 01:31 PM

Forgetting challenge-response systems in general, theirs specifically is definately broken. I could write a program to crack that in probably a couple hours, easily... they don't distort the letters in any way, they don't seem to use more than one font, and the background isn't 'noisy' so the letters would be easy for a computer to make out. (Easier for a computer with access to the RGB values than a human eye for some color combinations.)

Posted by: James Schend at March 1, 2005 03:25 PM

Not only are they annoying for humans, they're broken in general. Programmers are getting smarter all the time. I don't know if this link will work outside a campus that subscribes, but it details several algorithms for breaking such "security" measures:

I know I saw a website somewhere (on a university research website) a while back detailing a pattern recognition program that was something like 80% accurate on these tests, which was comparable to most humans. I can't find the link right now, but if I do, I'll post it here. This doesn't stop bots, just frustrates real users.

Posted by: anitsirK at March 1, 2005 03:43 PM

Ok, it was the same people from the .pdf I posted, but this version is definitely publicly accessible:

Posted by: anitsirK at March 1, 2005 03:44 PM

Usually, they are either so hard that a human has trouble figuring it out or so easy that a machine could figure it out.

Also, it seems to be fixed now.

Posted by: fuzzy at March 1, 2005 09:18 PM

I like the Motto, "Beyond Usability". Yea, so far beyond that it's UNUSABLE!

Posted by: Rat at March 2, 2005 09:58 AM

Ummm... that's the point.

Posted by: fuzzy at March 6, 2005 03:06 PM

that's the swiss for you, sweet watches awful computers

Posted by: hmmm at March 6, 2005 07:12 PM

Not only is that bad, but i encountered more than a few of those that are completely broken. I put in what is quite obviously the right combination, and it rejects it. THAT'S broken for you.

Posted by: Tyrian at July 13, 2005 11:33 AM

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