A flexible website security component, Telerik Captcha for ASP.NET AJAX will protect from automated spam your registration, comment, poll, content submission, etc. It generates distorted images of letters and numbers that are easily decipherable to humans - but not to spam bots.

Features

Major Modes for Protection

Telerik RadCaptcha provides two major strategies for protection against automated form submissions: image with modified symbols (captcha image) and automatic robots discovery.

Validation

The Captcha control by Telerik provides the ability to enable a validation through the ValidationGroup property. If the user does not enter the right captcha symbols the validators will display an error message in the ValidationSummary.

Flexible Layout

RadCaptcha allows for flexible layout customization. You can easily control the background, and the line noise of the image; specify the look of the captcha image, settings for fonts, number of characters, colors, etc.

Captcha Timeout

Telerik Captcha also features a configurable settable timeout to help defeat those "human bot shops". It allows you to specify a maximum number of minutes the Captcha Image will be cached and valid. If the submission is executed faster than the predefined value, it is assumed that the executor is a robot.