3D images: A human way to create Captchas

A new way to create Captchas using 3D images would make it much easier for human beings to pass while remaining really difficult for computers.

The new 3D image-based design for Captchas. Taylor Hayward

If you have registered a new e-mail account or tried to retrieve your, say, Gmail password, you'd be familiar with the use of Captchas, the challenge-response method to verify that the input is not generated by a computer.

The problem is that most existing Captchas, or Completely Automated Public Turing tests to tell Computers and Humans Apart, are actually quite inhuman. They are often made up of wavy lines, letters, and numbers shown in high contrast, different colors, or strike-throughs. Generally, they are distorted sometimes to the point that it's really hard for people to quickly make anything out of them. Personally, I've rarely been able to pass a Captcha the first time.

As the use of Captchas has been getting more and more popular, it's about time that somebody thought of a better test. And somebody sure has.

A blogger named Taylor Hayward has come up with a brilliant idea: using 3D images as Captchas.

The challenge is a 3D image of an animal, say of a rabbit's face. The list of answers would display different common animals from different angles, including a photo of the rabbit, this time of its side. Only a human brain would be able to quickly see that the challenge image and the second image on the answer list are of the same animal. Now you just need to click on the correct second image to pass the challenge.

This would make a great method to create Captchas that are fun, easy for humans to read, and, at least for now, close to impossible for computers to quickly pass. This is because humans' vision is so much more sophisticated than any existing computing algorithms. Something our eyes can see right away would take a lot of computing power to figure out.

For example, you can recognize a pair of shorts on top of a pile of clothing instantly. A computer wold take a long time and might even not be able to do that at all.

A computer might be able to circumvent such a Captcha method by clicking on all of the images, one after another. However, this outcome could be prevented by making the list longer and repeating the challenge from the beginning, if the first click was incorrect.

I really hope that Web sites would pick up this new design. In the end, I'd rather have to prove that I am human than prove that I am not a machine. And yes, they are two different things.

An example of Captchas currently used by Gmail Dong Ngo/CNET
About the author

CNET editor Dong Ngo has been involved with technology since 2000, starting with testing gadgets and writing code for CNET Labs' benchmarks. He now manages CNET San Francisco Labs, reviews 3D printers, networking/storage devices, and also writes about other topics from online security to new gadgets and how technology impacts the life of people around the world.

 

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