Excuse me, everyone, why do we always have to enter the verification code? What's the use of this?

CAPTCHA is the abbreviation of "fully automatic public Turing test tells computers and humans", and it is a public * * * fully automatic program to distinguish computers from humans. It can prevent malicious password cracking, ticket brushing and forum flooding, and effectively prevent a hacker from constantly trying to log in to a specific registered user by using a specific program brute force cracking method. In fact, using verification code is a popular way for many websites (such as China Merchants Bank's online personal banking and Baidu Community), and we have also realized this function in a relatively simple way.

Preventing malicious password cracking, ticket brushing and forum flooding can effectively prevent hackers from constantly trying to log in to specific registered users and using specific programs to violently crack. In fact, using verification code is a popular way for many websites (such as China Merchants Bank's online personal banking and Baidu Community), and we have also realized this function in a relatively simple way. Although it is a bit troublesome to log in, this function is necessary and important for the password security of netizens. However, we still remind everyone to protect their passwords and try to use passwords with more than 6 digits, including numbers, letters and symbols. Don't use a simple password such as 1234 or a password that is the same as or similar to the user name, so as to avoid the account being stolen and bring yourself unnecessary trouble.

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(1). The verification code is generally used to prevent batch registration, and it is difficult for people to see it, let alone the machine. Second, if Baidu Post Bar doesn't log in and post, you probably need to enter a verification code to prevent a large-scale anonymous reply. At present, many websites adopt verification code technology to prevent users from automatically registering, logging in and pouring water by robots. The so-called verification code is to generate a picture with a series of randomly generated numbers or symbols, and add some interference to the picture, such as drawing a few straight lines randomly and drawing some points (to prevent OCR). Users can identify the verification code information with naked eyes, enter the form and submit it to the website for verification. Only after the verification is successful can a function be used. (2) The verification code should be entered in the place where the user ID is registered and in major forums. (3) The commonly used verification code is 1, and all four digits and letters can be letters or numbers. Random four-digit string, the most original verification code, the verification effect is almost zero. 2.CSDN website users log in in GIF format, which is a commonly used random digital picture verification code. The characters in the picture are quite satisfactory, and the verification effect is better than the last one. People who don't have the basic knowledge of graphics and iconology can't be broken! Unfortunately, on the first day of using CSDN, the program to read it seems to have been published on the forum. What a pity! 2, Chinese characters are the latest verification codes registered at present, which are randomly generated and more difficult to type! For example, QQ complaint page 3, MS hotmail application is BMP format, random number+random capitalized English letters+random interference pixels+random position. 4, Korean or Japanese, now you have to type Korean on HF to register for MS, which is more difficult, so you have to study. 5. Google registered Gmail in JPG format, with random English letters+random color+random location+random length. 6. Other forums are random content in XBM format. 7. Question verification code: The question verification code is mainly filled in the form of question and answer. Its view is easier to identify and input than modular verification code, and the system can generate such things as "1+2=?" Let users answer questions, of course, such questions are randomly generated. Another kind of question verification code is a text-based question verification code, such as generating the question "What is the full name of China?" Of course, some websites will also give prompt answers or direct answers after the questions. What is the function of verification code? You must have been to the forum, right? Almost all formal forums require the input of verification code when registering, which is to prevent spammers from maliciously using the registration machine to register. This invention originated from Carnegie Mellon University in the United States is called CAPTCHA (Automatic Turing Test for Distinguishing between Human and Computer), because registrants need to recognize crooked words in pictures, and this work can only be done by real humans. You know, there are hundreds of millions of Internet users all over the world. For an individual, it only takes a few seconds to recognize words, but if all netizens are used, an unimaginable huge project can be completed, which is exactly what the CMU research team in Pittsburgh, Pennsylvania, USA is doing. Entrusted by a non-profit organization named "Internet Archives", the group wants to convert a large number of ancient books and manuscripts into electronic texts through OCR (Optical Character Recognition) software to facilitate computer storage and query. However, due to the poor quality of the manuscript, a bad computer will mispronounce one word for every ten words scanned. The only solution is manual inspection, which is obviously beyond the ability of one person or a group. Therefore, CMU has designed a powerful system called reCAPTCHA to let their computers seek help from humans. The specific methods are as follows: (1) Send the scanned text image that OCR software can't recognize to the world's major websites to replace the original verification code image; After the users of these websites correctly recognize these words, their answers will be sent back to CMU. In order to improve the accuracy of text recognition, users are often required to recognize two words whose answers are known. In this way, the user who correctly identifies a word with the answer is likely to correctly identify another word. Sometimes, CMU will also submit an unrecognized word to different users. If you get the same answer, then the answer is definitely correct. Because many popular websites, such as Facebook, Twitter and StumbleUpon, have adopted reCAPTCHA, CMU can now process about one million words every day. However, at the current rate, it is estimated that it will take another 400 years to digitize all the texts provided by the Internet Archives. (4) At present, the popular verification method is SMS verification code, which also provides security for websites or users to log in. People in need can call me, and I can provide a full set of SMS verification services.