If asked about one irritating thing on cyber world, spamming would if not on the top, then at least in top three. Coders are always after finding ways to outwit spammers. Captchas is one of the fruits such efforts have produced. They are referred to those illegible code words which are designed to dodge spammers, often asked to input before proceeding to the required page.
But the bad news is that researchers at Stanford University have been successful in decoding these captchas through bots. So the technique isn’t quite dependable anymore.
The team at Stanford has basically developed “decaptcha” softwares which enables the computer to render the captcha code legible by cleaning up the text.
The software was successful in cleaning up 66% of Visa’s Authorize.net Captchas, 70% of Blizzard’s Entertainment and 73% of captcha.com’s captcha.
Its results on some other website were not that effect such as the extent to which it could decode eBay’s captcha was 43% and 24% of those of Reddit’s. Before the Stanford fellows, many other teams have been working to develop such decoders and that often under the same label.
The team also pinpointed another negative point of captchas in their paper published about this research. They have found that these captchas are hard for common users to comprehend and type in. the audio captchas, apparently provided to facilitate users, is even harder to understand.
Captchas were originally uncovered by the search engine “Alta Vista” in early 2000s. The word is basically an acronym for “Completely Automated Public Turing test to tell Computers and Humans Apart” and as it suggests, these captchas were introduced for checking and discouraging automatic submission of URLs.
Different types of Captchas are now available ranging from geometric captchas, math captchas and even the “sexy” ones. Some of them are specified for advertisements as well called advertising captchas.
The use of captchas is now becoming uncommon due to the difficulty faced by the users in comprehending them. Web masters now use alternate methods such as asking a common and easy question for instance “what comes after T?”, or asking to check a check box or sometimes Short Messaging Service (SMS) is utilized for this purpose as well.