验证码作用（Verification function）.docVIP

验证码作用（Verification function） The role of verification code in the Forum Because your WEB client station will sometimes encounter malicious attacks, one of the most common attack means of identity deception by _ Write some code in the client script, and then use the client in the website forum, repeatedly landing, or the attacker creates a HTML form, if the form contains your registration form or posting forms for the same field, and then use http-post to transmit data to the server, the server will Perform the corresponding creation of accounts, submit garbage data, and other operations, if the server itself can not effectively verify and reject this illegal operation, it will be very serious consumption Its system resources reduce site performance and even crash programs The popular way to judge whether access to a WEB program is legitimate or malicious is to adopt a technique called character verification The WEB site, like the current Web Forum, uses the method to provide customers with pictures containing a string of characters that users must read These strings are then submitted with a form created by the user, such as a login form or a post form Because people can easily read the figures in the picture, but if it is a piece of client-side attack code, it is difficult to identify the verification code by general means This ensures that the current access comes from a person, not a machine Verification Code: is a random set of numbers or symbols, generate a picture, some pictures with interference pixel (to prevent OCR), by which users eye identification verification code input information, submit site verification, after successful authentication to use a function. Effect： Verification code is generally to prevent the use of robots automatically batch registration, for a specific registered users with specific procedures, brute force way to constantly landing, irrigation. Because the verification code is a picture of a combination of numbers or symbols, the hu