Wednesday, September 28, 2011

Why is it so hard to enter the CAPTCHAs

Get to know how the Methods Cheaters Use to Crack CAPTCHAs

Do you know why CAPTCHA codes are so hard to enter? Cheaters can use bots to enter sweepstakes for them or vote for their contest entries, exploiting code to enter more often than the rules allow. However by using on sweepstakes forms, will CAPTCHA codes prevent bots?

Anyways it is like a game of cat and mouse, cheaters are always trying to crack CAPTCHAs, and companies are trying to strengthen their security to make them harder to get around and at the mean time, regular people are feeling hard to enter the codes.

Use OCR to Avoid CAPTCHA

The way OCR, which stands for Optical Character Recognition, is for computers to identify text from images. If you want to scan a document into your computer and edit it like any of your electronic documents, you'll scan the image into the computer and then the related text will be generated from the OCR software. Cheaters can use OCR software to break the code with a perfect, clear text CAPTCHA. 

It is the reason that so many CAPTCHA codes are blurry, have wavy lines behind them, turn the letters sideways, or otherwise make it hard to read the text.
When you are trying to scan a document, you'll notice that while many words scan through without problems, any smears or smudges on the paper, or anything else that makes the text a little unclear, there could be errors and confusing words generated from the OCR software. By this way the cheaters will not be able to break the code since the CAPTCHA codes are hard to read.

CAPTCHA Codes appearing in Other Websites

It is hard for computers to enter the CAPTCHAs automatically while it is easy for humans to solve it. However if you are unwittingly solving the CAPTCHAs it will not work.

By passing the code to other website, where people enter the code to get access to some other feature, cheaters and spammers could get around CAPTCHAs. It is working like when they are trying to get access to an (often pornographic) picture by solving a puzzle or typing a code.

So the CAPTCHAs expire very quickly because of the things above. If in every few seconds a new CAPTCHA needs to be entered, which could reduce the odds that cheaters can trick someone into typing the response very quick.

Get paid to Crack CAPTCHAs

There are some companies offering money to crack CAPTCHAs to those cheaters. They work in a similar method to the trick above, but they pass the CAPTCHA codes to people working in sweat shops in third-world countries to solve. Such kind of crack can be prevented by a fast-expiring CAPTCHA.

Poorly-Coded CAPTCHAs Exploited

It is possible to guess the desired result from the code or to have the same CAPTCHA accepted over and over again when some CAPTCHAs are not coded correctly. Fortunately, some free CAPTCHAs such as Google's Recaptcha can avoid the problem as this.

Extra words

It is considered to be illegal to circumvent CAPTCA because it violates the DMCA. As long as there's profit in circumventing CAPTCHAs, criminals will always look for new ways to crack them, while companies will try new methods to boost security.

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