When sign in into a website, to open an e-mail account for example, we frequently face a request to type in a code including letters and numbers. These characters are shown on a distored image to be identify only by human beings. These images are known as “captchas”. They were introduced a few years ago as a security measure to stop access to HTML forms by computarized programs attempting to obtain multiple e-mail addresses and other records from the web.
The purpose of captchas is that only a human being would be able to decipher them. Since they are distored images with characters in different sizes or with geometrical figures on the background, OCR programs could hardly identify them. However, and in most cases, an OCR can be “trained” by a person to decipher the characters in a captcha. Therefore, many websites change their captchas constantly to prevent access by automated programs.
Sometimes captchas become also a challenge for humans, since people with impaired vision might find them hard to solve.
With its captchas, the PHP scripts generated by Forms To Go offer you higher protection for your HTML forms. Based on our users’ comments and the reviews we have made to our website, we are able to confirm that spam or temporary forms’ hijacking has been almost eliminated.
For more information about “captchas” and strategies on how to ”defeat” them, go to:
http://en.wikipedia.org/wiki/Captcha
One of the most creative captcha-defeating projects we have found is one in which humans are tricked into typing in a captcha for a spammer. For example…
A person sees banner of a website offering free porn pictures or software downloads. To access them the user only needs to type in the captcha shown on the banner or website. Attracted by this “excellent deal”, the user enters the characters of the captcha. But in fact, the captcha belongs to a website where the spammer wants to log into. A program or robot connects to the web form, gets the captcha image and shows it to the user, who naively types in the captcha to get what he is been offered: a picture or a download. Or he might never get any of these. But with the solved captcha, the spammer already achieved his goal, signin into the website, an automatically use the account, like an email account, for spamming or other use. Sometimes they get many accounts on the same website.
With this kind of tactic, spammers can solve many captchas in just one day.
We would like to know your opinion on captchas, whether you think they are being used properly on the web or if you know about a website offering a creative captcha that would be hard to “defeat”.