Users are asked to identify specific objects or characters within an image. For example, selecting all images containing traffic lights or crosswalks. Humans can quickly identify these objects, while bots struggle with the complex visual processing required.
Users are required to enter characters displayed in distorted or warped text. The distortion makes it challenging for bots to read the text accurately. It's a classic captcha option that has been used for years.
Users are prompted to listen to an audio recording and enter the characters or numbers they hear. This option caters to users with visual impairments and adds an extra layer of complexity for bots, as voice recognition can be tricky to implement accurately.
Users are asked to solve a simple puzzle, such as arranging jumbled pieces to form a complete image or dragging and dropping objects into the correct positions. These puzzles are easy for humans but harder for automated scripts.
Users may be asked to solve a basic arithmetic problem, like adding or subtracting two numbers. Since bots are generally not designed to perform such calculations, this type of captcha can deter automated attacks.
This is a hidden field in a form that only bots would fill out, as humans can't see it. If the field is filled, the submission is likely from a bot, and the request can be rejected.
Instead of challenging users with puzzles or tasks, this approach analyzes user behavior, such as mouse movement patterns or typing speed, to determine if the user is human or a bot. It adds an additional layer of security without any explicit user input.
This type of captcha assesses the user's location and compares it with their provided information or previous behavior. Unusual locations or inconsistencies might trigger a captcha challenge to confirm the user's identity.
Users are asked to log in or verify their identity using their social media accounts, like Google reCAPTCHA or Facebook Login. This relies on the social media platform's authentication processes to determine the user's legitimacy.
Remember that captchas should strike a balance between security and user experience. Overly complex captchas can frustrate legitimate users, leading to a negative impact on the website's usability. Therefore, it's essential to choose appropriate captcha options based on the specific security requirements of the online system.