The story of the Captcha

The old netizens probably all remember, just started the internet time, there is no verification code (CAPCHA) such a thing. The result is that http://www.aliyun.com/zixun/aggregation/8438.html "> spam comments and spam can be easily passed through any of the website's registration procedures by bombing people's eyeballs in various ways."

The first to solve this problem is Yahoo--as the most important free email provider in the early days of the Internet, on the one hand, they are addressing the hundreds of spam bombings that users encounter every day, and their own free mailboxes, which are the favorites of spam, that consume countless resources to block spam, are from their own servers. This makes Yahoo start to seriously consider how to solve the problem of human machine identification.

The first appearance of the Internet CAPTHCA

They found a genius--luis von Ahn, who was just 21 years old. Luis Von Ahn's solution was the one that made the people frown, but capcha the computer's shrug. Computer identification technology is still very backward, for distorted, contaminated text, can not be identified. But humans can easily recognize these words. This is a simple and ingenious design, the computer will first produce a random string, and then use the program to the image of the string randomly contaminated, distorted, and then displayed to the monitor before the person or machine. Those who can recognize these characters are human.

The story is not finished, and Luis Von Ahn is the kind of scientist who pursues perfection. When the world's 1 billion of millions of people spend a few seconds each day participating in the simple activity of identifying words, he begins to wonder if the waste of human brain can be better used.

The final design of Luis Von Ahn is to let people use these brains to solve the digital books that some computers cannot solve.

Before the computer age, printing had existed for hundreds of of years, but the books and newspapers produced by these printing machines were analog signals to computers, only in the form of images, not in digital form. However, the early printing is not accurate, the size of the text is different, image. And because the print age, with a variety of subtle defects and pollution. It's not a big problem for the human eye, but it's a problem for the computer.

Currently in Google, Yahoo, YouTube and other sites can see the double Capcha, one is the need to identify the document image, a computer-generated Capcha

Thus, in 2002, Luis Von Ahn began to allow Capcha to cite a variety of text images that could not be identified by computer, and tens of thousands of websites now use his new generation of Capcha. Help identify millions of ancient documents every day.

The problem is that for the first Capcha, the computer actually knows the answer. And Luis wants people to recognize the text, the computer actually does not know the answer, then how to verify the return of the answer in the end is not true?

The solution to this problem still reflects Luis's consistent simplicity and elegance, which allows people to identify two of them each time, rather than a capcha, one from a randomly generated string from the computer, and the other a character image that is not recognized by the computer selected from the document. As long as the answer to the previous string is correct, it is judged that people are correct in identifying the latter capcha.

In this way, Luis's capcha2.0 has helped complete the digital archive of the New York Times for 130 years-a project that could have cost countless hours and resources, and has been completed in a few months by everyone.

This, of course, is the human flesh business that Americans find in Capcha. And the opposite, know how Chinese and Indians from Capcha to find human business opportunities?

In simple terms, through a series of program transitions, Asian labor-intensive industries have concentrated on a handful of Capcha-Capcha to identify the various spam registration and electronic game coin farmers, who work to identify capcha for spam registration software, Once they were able to impersonate a human being, each identified with a half rupee, each day needed to identify thousands of capcha.

Labour-intensive economies and capital-intensive economies are priced so differently from human brainpower.

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