Who Needs CAPTCHA?

A CAPTCHA or Completely Automated Public Turing test to tell Computers and Humans Apart is basically a kind of test that helps to distinguish a computer from a human being. It is under the trademark of Carnegie Mellon University. You can visit http://www.protectwebform.com/ for detailed information on CAPTCHA.

A CAPTCHA requests the user to take a test. Any user who provides the correct answer is considered to be a human. A very common instance of a CAPTCHA is to ask the user to key in letters from a distorted image. The sequence includes alphabets and numbers. If the user keys in the correct sequence, he is considered to be a human or else a machine. A smart CAPTCHA is pretty easy to implement. You can get the details from http://www.protectwebform.com/smartcaptcha.

Website owners have to guard against spammers yet they need feedback from the visitors to their site. Spammers are always on the look out to grab your email id and use it for various purposes without your permission. One option is that you can go in for automated programs, called bots, to let them scan your website and parse out your mail id.

Another option is CAPTCHA that does not allow the spammers to get access to your email ids. Many websites and sign-up pages use CAPTHCA. It assumes that computer programs cannot read distorted characters. It is considered fairly reliable.

CAPTCHA has become very popular in the past few years because it is a program that can create tests which only humans can clear. Since the program is fully automated there is virtually no chance of any human intervention. No wonder, most website owners go for it.

CAPTCHAs prevent abuse of a system. Once spammers get access to your mail id, then you are trapped. You will be bombarded with spam mails and you can never be sure what your id will be used for.

In other words, CAPTCHA not only prevents encroachment by spammers for commercial purpose, it also protects the systems that are gullible to spam like, the webmail services of Gmail, Hotmail, and Yahoo. They also help prevent automated postings on online blogs. CAPTCHA helps in enforcing a usage policy and prevents any kind of deviation from the policy. This is required in case a service allows automated use but within a limit.

There have been numerous efforts at creating CAPTCHAs that are handier. Such endeavours usually include the use of JavaScript, mathematical questions (like "what is 1+1"), or simple questions requiring common sense (for instance "what color is the sky"). These attempts infringe on one or both of the philosophy of CAPTCHAs. Either they cannot be automatically created or they can be easily split given the condition of false intelligence. So, the only security these CAPTCHAs provide is safety through obscurity.

Article Source: http://www.myaddirectory.com

Oleg is an expert on CAPTCHA design and development. Click to find out more about his new CAPTCHA Plugin technology.

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