With the rapid development of the internet, online security has become a major concern for both websites and users. In order to prevent fraudulent activities and protect sensitive information, the use of Captcha has become widespread. Captcha is an acronym for “Completely Automated Public Turing test to tell Computers and Humans Apart”. Captcha is a verification process that requires users to prove their identity as a human rather than a computer program. It typically presents users with distorted images or random characters that they must decipher and input correctly. This helps to ensure that the information being entered is legitimate and not generated by bots or automated programs.The primary goal of Captcha is to protect websites from spam, scams, and unauthorized access. By implementing this verification process, websites can effectively prevent automated programs from exploiting vulnerabilities and attacking their systems. Captcha also helps to safeguard user data by ensuring that only real users have access to sensitive information.Furthermore, Captcha plays a crucial role in online transactions, such as e-commerce and online banking. It adds an extra layer of security by verifying that the person entering the information is a genuine user and not a potential hacker.In conclusion, Captcha is an essential tool in ensuring online security. By requiring users to prove their human identity, it effectively protects websites from fraudulent activities and safeguards sensitive information. As online threats continue to evolve, the implementation of Captcha remains vital in building a secure online environment.。