What is a verification code?

The verification code is a public * * * automatic program, which is used to distinguish whether the user is a computer or a person. Its function is to prevent malicious code 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. The verification code usually consists of some lines and some irregular characters, and its main function is to prevent some hackers from stealing password data. Verification codes are divided into four categories:

1, folding Gif animation verification code

Mainstream verification codes are easily recognized by ocr software by providing static pictures. Some websites provide dynamic verification code pictures of GIF, and it is difficult for the recognizer to identify which layer is the real verification code picture. It can provide a clear picture and prevent the recognizer from recognizing it more effectively.

2. Fold SMS verification code

Mobile phone verification code is the most effective verification code system by sending verification code to mobile phone. Large websites, especially shopping websites, provide SMS verification code function, which can accurately and safely ensure the safety of shopping and verify the correctness of users.

3. Fold the phone voice verification code

As long as the user's mobile phone or landline can answer the phone normally, it will definitely receive the voice verification code, which can automatically broadcast the voice, and at the same time, the short message can also be sent to the user's mobile phone at the same time, realizing double insurance and ensuring foolproof.

4. Fold the video verification code

Video captcha is a rookie in captcha. The verification code composed of random numbers, letters and Chinese in video verification code is dynamically embedded in videos in MP4, flv and other formats, which increases the difficulty of cracking.