What is the verification code for? Why should I enter the verification code?

CAPTCHA is the abbreviation of "automatic public Turing test to distinguish between computer and human", and it is a public * * * automatic program used to distinguish whether the user is a computer or a human.

It can prevent malicious batch registration, 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.

Generally speaking, the computer will produce a verification code question (a picture will be generated by a series of randomly generated numbers or symbols), but this verification question is unrecognizable by the computer itself and can only be answered by human beings, so the computer can judge whether the person is operating or the machine is operating according to the input of the verification code. So as to play a preventive role.

Common verification codes are GIF animation verification code and SMS verification code. With the development of technology, computers can slowly crack some conventional verification codes, so it is necessary to use more advanced algorithms and methods to generate verification codes. The common way is to add some interference to the verification code, such as drawing a few straight lines and some points at random, in fact, in order to prevent the computer from automatically recognizing it, which also makes the verification code sometimes unclear to people (so it is generally similar to "I can't see it clearly, change it".