Why do you have to enter the verification code when you log in to the web page?

What the captcha does:

1）.Captcha is generally to prevent batch registration, and it looks difficult to the human eye, let alone a machine. Two like the post bar is not logged in to post to enter the verification code is probably to prevent the occurrence of large-scale anonymous replies At present, many ** in order to prevent users from using robots to automatically register, log in, and irrigate, all use verification code technology.

The so-called verification code is to generate a string of randomly generated numbers or symbols, add some interfering pixels (to prevent OCR), and the user will recognize the verification code information by the naked eye, enter the form to submit** verification, and only after the verification is successful can a certain function be used.

Common captchas.

1. Four-digit number, a random one-digit string, the most original verification code, the verification effect is almost zero.

2. CSDN** user login is in GIF format, which is currently commonly used as a random number ** verification code. **The characters on the ** are more decent, and the verification effect is better than the previous one. For those who do not have basic graphic iconography knowledge, it is unbreakable!

It's a pity that the program that reads it, on the first day that csdn used it, seems to have been published in the forum, which is really pitiful!

3,QQ**User login is in png format,**Random numbers + random capital English letters,The whole composition is a bit flamboyant,Every time you refresh it,Each character will change its position! Sometimes the ** that comes out can't be recognized by the human eye, it's amazing....

4. When MS hotmail is applied, it is in bmp format, random number + random capital English letter + random interference pixel + random position.

5, Google's gmail registration is in jpg format, random English letters + random color + random position + random length. 6. Other major forums are in XBM format, and the content is random.

Significance: In order to prevent users from using robots to automatically register, log in, and irrigate, many ** have adopted captcha technology. The so-called verification code is to generate a string of randomly generated numbers or symbols, add some interfering pixels (to prevent OCR), and the user will recognize the verification code information by the naked eye, enter the form to submit** verification, and only after the verification is successful can a certain function be used.

In order not to let the program identify the messy message,

Someone maliciously registers with registered software on ** for various purposes. Such a thing can be avoided with a captcha.

The reason for this is that the captcha requires a real person to identify the content of the captcha. In other words, it is very easy for a person to recognize a captcha, but it is very difficult to use software to recognize a captcha.

Therefore, the use of verification codes ensures that people participate in the registration process, and it also avoids someone maliciously using the registration software to attack**.

Sometimes there are malicious attacks by hackers, one of the most common attack methods is identity spoofing, which is done by writing some ** in the client-side script, and then using its client to log in repeatedly in **, forum, or the attacker creates an html form, if the form contains the same fields such as your registration form or posting form, and then exploits"http-post"If the server itself cannot effectively verify and reject this illegal operation, it will seriously consume its system resources, reduce the performance and even crash the program.

At this time, there must be a way to prevent this malicious attack in time, then the verification code is used to prevent these unfriendly netizens from repeatedly registering IDs on the **, logging in**, repeatedly reading and writing **database, causing the shortage of server resources to affect the legitimate access of other normal users, and reducing the possibility of the super administrator account or ordinary legitimate user account being deciphered, so as to add a measure to protect the interests of **and**users.

It is usually made in the form of **, because the character text is too easy to be read by the program, in order to further prevent the captcha from being recognized by the program, it is usually necessary to use the program to process the captcha text crookedly, for example, when we apply for a free QQ number, it is required to enter 8 graphic Chinese characters, and some also add a lot of interfering pixels and lines, so that the captcha can only be recognized by human eyes, so it must be entered manually every time, when** When the login system program judges that the font code you enter is incorrect with what it gives, it will not read and write the database, which greatly reduces the burden and improves the security.

The verification code does not match the server verification system, so you have to be comfortable again, it has nothing to do with you!

If someone else fraudulently uses your account information, the other party's mobile phone cannot be operated due to unsuccessful verification, which is very helpful to protect your account information.

Yes, but I can't see a lot of it.

It may be a problem with your browser.,You can close the page and reopen it.,Or open it again the next day.,I've encountered such a situation before.,Click on the captcha**,And then enter it on.。

If QQ Browser requires a verification code every time you log in, it may be because of the following situations:

1. There are certain security risks in the account, for example, the QQ account password is too simple and the security factor is too low.

2. The QQ password was stolen, and I logged in to the account to send advertisements or fraudulent messages without my knowledge, which was detected by the system, so identity verification is required.

3. The IP address is abnormal, and the IP address of the login location is inconsistent with the commonly used IP address.

Browser settings issue, tools -inernet options -advanced-reset

Click on your browser's Tools, Internet Options and then delete the files to delete cookies

Then, click Start Run : Enter regsvr32 and select OK.

Click again to start running: Enter regsvr32 again and select OK.

When you're done, restart and log in.

Pro, the problem of setting is generally now the browser is trouble-free and effort-saving, and the web page is not deleted The next time you open it, it's fast, but there is a problem of repeated errors in the verification code.。。。

Will your home's network IP change itself Is it the router you use?

The reason why you need to enter a verification code every time you log in to QQ browser:

1. There are certain security risks in the account, such as the account password is too simple.

2. The QQ password has been stolen and is used by others to send advertisements or fraudulent messages without knowing it, so that it is detected by the system.

3. The IP address is abnormal, and the login IP is different every time.

4. Viruses or Trojans in the computer, check and kill viruses or reinstall QQ.

It is recommended that QQ set up encryption, log in to QQ, etc., set up account login protection, and complete security measures will greatly reduce the probability of verification codes.

It should be the result of having a field login.