Captcha in asp.net using c#.net

mscaptcha.xml:
<?xml version="1.0"?>
<doc>
    <assembly>
        <name>MSCaptcha</name>
    </assembly>
    <members>
        <member name="M:MSCaptcha.CaptchaControl.ValidateCaptcha(System.String)">
            <summary>
            Validate the user's text against the CAPTCHA text
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaControl.HtmlColor(System.Drawing.Color)">
            <summary>
            returns HTML-ized color strings
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaControl.CssStyle">
            <summary>
            returns css "style=" tag for this control
            based on standard control visual properties
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaControl.Render(System.Web.UI.HtmlTextWriter)">
            <summary>
            render raw control HTML to the page
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaControl.GenerateNewCaptcha">
            <summary>
            generate a new captcha and store it in the ASP.NET Cache by unique GUID
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaControl.System#Web#UI#IPostBackDataHandler#LoadPostData(System.String,System.Collections.Specialized.NameValueCollection)">
            <summary>
            Retrieve the user's CAPTCHA input from the posted data
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaControl.BackColor">
            <summary>
            Background color for the captcha image
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaControl.FontColor">
            <summary>
            Color of captcha text
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaControl.NoiseColor">
            <summary>
            Color for dots in the background noise
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaControl.LineColor">
            <summary>
            Color for the background lines of the captcha image
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaControl.IsDesignMode">
            <summary>
            are we in design mode?
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.RenderImage">
            <summary>
            Forces a new Captcha image to be generated using current property value settings.
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.RandomFontFamily">
            <summary>
            Returns a random font family from the font whitelist
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.GenerateRandomText">
            <summary>
            generate random text for the CAPTCHA
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.RandomPoint(System.Int32,System.Int32,System.Int32,System.Int32)">
            <summary>
            Returns a random point within the specified x and y ranges
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.RandomPoint(System.Drawing.Rectangle)">
            <summary>
            Returns a random point within the specified rectangle
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.TextPath(System.String,System.Drawing.Font,System.Drawing.Rectangle)">
            <summary>
            Returns a GraphicsPath containing the specified string and font
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.GetFont">
            <summary>
            Returns the CAPTCHA font in an appropriate size
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.GenerateImagePrivate">
            <summary>
            Renders the CAPTCHA image
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.WarpText(System.Drawing.Drawing2D.GraphicsPath,System.Drawing.Rectangle)">
            <summary>
            Warp the provided text GraphicsPath by a variable amount
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.AddNoise(System.Drawing.Graphics,System.Drawing.Rectangle)">
            <summary>
            Add a variable level of graphic noise to the image
            </summary>
        </member>
        <member name="M:MSCaptcha.CaptchaImage.AddLine(System.Drawing.Graphics,System.Drawing.Rectangle)">
            <summary>
            Add variable level of curved lines to the image
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.UniqueId">
            <summary>
            Returns a GUID that uniquely identifies this Captcha
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.RenderedAt">
            <summary>
            Returns the date and time this image was last rendered
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.Font">
            <summary>
            Font family to use when drawing the Captcha text. If no font is provided, a random font will be chosen from the font whitelist for each character.
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.FontWarp">
            <summary>
            Amount of random warping to apply to the Captcha text.
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.BackgroundNoise">
            <summary>
            Amount of background noise to apply to the Captcha image.
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.TextChars">
            <summary>
            A string of valid characters to use in the Captcha text.
            A random character will be selected from this string for each character.
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.TextLength">
            <summary>
            Number of characters to use in the Captcha text.
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.Text">
            <summary>
            Returns the randomly generated Captcha text.
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.Width">
            <summary>
            Width of Captcha image to generate, in pixels
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.Height">
            <summary>
            Height of Captcha image to generate, in pixels
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.FontWhitelist">
            <summary>
            A semicolon-delimited list of valid fonts to use when no font is provided.
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.BackColor">
            <summary>
            Background color for the captcha image
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.FontColor">
            <summary>
            Color of captcha text
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.NoiseColor">
            <summary>
            Color for dots in the background noise
            </summary>
        </member>
        <member name="P:MSCaptcha.CaptchaImage.LineColor">
            <summary>
            Color for the background lines of the captcha image
            </summary>
        </member>
        <member name="T:MSCaptcha.CaptchaImage.FontWarpFactor">
            <summary>
            Amount of random font warping to apply to rendered text
            </summary>
        </member>
        <member name="T:MSCaptcha.CaptchaImage.BackgroundNoiseLevel">
            <summary>
            Amount of background noise to add to rendered image
            </summary>
        </member>
        <member name="T:MSCaptcha.CaptchaImage.LineNoiseLevel">
            <summary>
            Amount of curved line noise to add to rendered image
            </summary>
        </member>
    </members>
</doc>

web.config:

<system.web>
   <httpHandlers>
      <add verb="GET" path="CaptchaImage.axd" type="MSCaptcha.CaptchaImageHandler, MSCaptcha"/>
    </httpHandlers>
</system.web>


Adding Captcha dll :


  <cc1:CaptchaControl ID="Captcha1" runat="server" CaptchaBackgroundNoise="Low" CaptchaLength="5"
                                                        CaptchaHeight="60" CaptchaWidth="160" CaptchaLineNoise="None" CaptchaMinTimeout="5"
                                                        CaptchaMaxTimeout="240" FontColor="#529E00" BackColor="Silver" />