I must not be human.

About two months ago I got a good chuckle from an image on Flickr which I stumbled upon through Digg. It was a screenshot of an online form containing an absurdly difficult CAPTCHA. For those of you who don’t know what that is, a CAPTCHA is essentially a way of ensuring that certain responses are coming from a human. They are used to protect from automated attacks and are normally in the form of images with grainy, distorted backgrounds overlaid with warped text. Anyway, this is what the CAPTCHA looked like:

Are you able to decipher it? Cause I sure as hell couldn’t – am I not human?

This got me thinking. I read an article on Arstechina which talked about how the onslaught of CAPTCHA breakers has brought about new methods of administering attacks that even compromise Gmail and Hotmail. So how should we deal with this problem? One obvious possibility is to ramp up the complexity of CAPTCHAs and accept the ‘casualties’ of human ineptitude [myself included] – or maybe we can find a happy medium in which cultural references and contextual hints are used as a filter.

Users can be prompted to select from multiple words within a CAPTCHA to go in a sentence. For example – fill in the following sentence:  Little ___ riding hood and the big bad wolf [given a number of color names within the CAPTCHA]. Another solution is to make the CAPTCHA itself a question – “What color is a giraffe?” or “Does a hawk have feathers?”  With these methods, however, there is no guarantee that every human is capable of making the correct connections.

Another possibility would be to find entirely new alternatives. Users can be asked to locate an object within a picture; or be asked to click on specific points in a certain order. Users can be shown a picture of an object and be told to name it. External style sheets can be used to create hidden fields that only bots will complete. Questions can incorporate elementary arithmetic. One very simple fix would be to use animated gifs instead of static images.

On a side note, I watched a documentary in which CAPTCHAs were used as a means of deciphering physically old literature. Pages from antique manuscripts and books illegible to OCR systems were broken down and distributed as CAPTCHAs. I found this to be quite ingenious as it served the needs of various people.