Why do I need a captcha for everything?

You may have used some unofficial software to log in to QQ, or you have hung up on ** and logged in to Q in some unsafe places, such as Internet cafes with insecurity factors. 3. The reason for the existence of virus Trojans in your computer, such as sending some virus messages or deceptive messages when you are infected by a virus, are caused by viruses. 4. Sending QQ messages maliciously, being reported by others, and forcibly deleting a large number of friends.

5. At the same time, please do not provide the password during the time period of your login number so that your friends can log in elsewhere to try yours, it may also be caused by network problems, such as using **, the network is unstable, and it will appear. Solution: Please use antivirus software to fully kill your computer in safe mode, it is recommended that you clear the local chat history of this number (search for the folder named with the number in the QQ installation directory to delete!).

In between, please uninstall all previous QQ versions, **the latest official QQ version to use. There is also the reported QQ number, please be patient and wait for the passage of the observation time, and when the time passes, the verification code will disappear, but you need to re-operate it like the above. The solution to the requirement to enter a verification code for the existence of a double main number in the user's number Due to the recent discovery that a large number of numbers have a double main number (that is, two people know that the number password is used at different times and places at the same time), it is not easy to be discovered by the original number owner, so we have launched a verification code to attract the attention of the real number owner and reduce the loss of the original owner.

1. Sending advertising messages: That is, they may be used by others to send advertisements or fraudulent messages without your knowledge, which will be detected by the system. 2. Remote login:

That is, your number often logs in in one place, and when it is suddenly detected that the login location has changed, a verification code will be added for security purposes 3. The number has hang-up behavior: Usually the number thief will use the help of the user to hang up to steal the user's property and number. Workaround:

1. Change the password immediately after discovering the verification code, and kill the Trojan 2. After you are required to verify the password, it will enter the observation period, and the system will automatically cancel it after 10 to 20 days of normal use; If the password is leaked again during this period, you will continue to be asked to enter a verification code.

Hello:1Changed the IP,I don't know if it's Netcom or Tietong's will appear in the kind of situation you said,IP changes quickly,The system scans your QQ abnormally, so you have to verify,Not to log in to verify,Sometimes other operations have to be verified,Prevent not my own operation。 2：

There is a virus on the computer, your QQ number is known by others, and your number is used to send bad information 3: There is a lot of garbage in the open space IE, and it has not been cleaned up for a long time, 4: The impact of network speed is over when entering the verification code, There is a situation of 1:

Landing for two weeks will be fine,. There are 2 cases: It is recommended to change the password as soon as possible and set the password card There are 3 cases:

Clean up the system junk and fix IE There are 4 cases: network speed problems, it does not mean that this will be the case in the future.

When you enter the wrong password, he will also show that the verification code is incorrect, so make sure the password is correct first.

Let me explain what the captcha does!

Captcha is used to prevent brute force attacks!

To know that if we want to prevent it, we must first know what the principle of brute-force cracking is!

Brute-force cracking is the use of programs to enter usernames and passwords in a short period of time according to certain rules, and test them one by one!

Effects such as: username 111 password 111 ; Username 222 Password 222 ; Username 333 Password 333...

Relatively easy to hack usernames and passwords for simple users!

The captcha will be replaced with a different number every time it is refreshed, without any regularity, if the captcha or verification is not filled.

If the code is incorrect, the system does not need to compare the password with the database, and returns it directly, so that brute-force cracking cannot be carried out.

Why is the captcha neither ** nor a number?

The reason is very simple, if it is**or a number, by looking at the source** or other methods, you can get the information of the verification code, improve the violence.

After the force cracks the program, brute force can still be carried out. The verification code is generated according to the program, and it is displayed with the information calculated by the program.

is shown on the page.

I don't know if my explanation can make you understand!