ASP.NET CAPTCHA Application Config Settings C# Code Example

The ASP.NET SimpleCaptcha application config settings example project shows how to configure BotDetect CAPTCHA challenges by overriding SimpleCaptcha control defaults in application configuration files.

First Time Here?

Check the BotDetect Developer Crash Course for key integration steps.

BotDetect allows user-defined customization of many SimpleCaptcha options through a special <botDetect> section of the botdetect.xml file.

SimpleCaptcha settings from this configuration file will apply to all SimpleCaptcha challenges shown on forms in the applications, and will act as defaults with which all SimpleCaptcha objects will be created. This makes configuration file settings the simplest and most convenient way of SimpleCaptcha customization for most use cases.

The web.config file file used in this code example contains detailed descriptions and explanations of the many customizable SimpleCaptcha options exposed by the BotDetect ASP.NET Captcha Simple API configuration API.

Download the BotDetect ASP.NET CAPTCHA Component and run this example

Visual Studio 2005-2017 / .NET 2.0 and onwards

By default, the .NET C# version of the ASP.NET SimpleCaptcha application config settings example project is installed at:
C:\Program Files\Captcha Inc\BotDetect 4 CAPTCHA Component\Asp.Net\.NET\WebApp\SimpleAPI\CaptchaApplicationConfigSettingsExample\CSharp

You can also run it from the BotDetect Start Menu:
Programs > Captcha Inc > BotDetect 4 CAPTCHA Component > ASP.NET > ASP.NET Examples > Run .NET Examples

Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" 
Inherits="_Default" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
  <title>BotDetect ASP.NET CAPTCHA Options: Application Config Settings Code 
  Example</title>

  <script type="text/javascript" 

</head>
<body>
  <form runat="server" class="column" id="form1">
    <h1>BotDetect ASP.NET CAPTCHA Options:
      <br />
      Application Config Settings Code Example</h1>
    <fieldset>
      <legend>ASP.NET WebForm CAPTCHA Validation</legend>
      <p class="prompt">
        <label for="CaptchaCodeTextBox">Retype the characters from the picture:</label</p>
      <BotDetect:WebFormsSimpleCaptcha runat="server" ID="ExampleCaptcha" 
 />
      <div class="validationDiv">
        <asp:TextBox ID="CaptchaCodeTextBox" runat="server"></asp:TextBox>
        <asp:Button ID="ValidateCaptchaButton" runat="server" />
        <asp:Label ID="CaptchaCorrectLabel" runat="server" CssClass="correct"></asp:Label>
        <asp:Label ID="CaptchaIncorrectLabel" runat="server" 
        CssClass="incorrect"></asp:Label>
      </div>
    </fieldset>
  </form>
</body>

Default.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{
  protected void Page_PreRender(object sender, EventArgs e)
  {
    // initial page setup
    if (!IsPostBack)
    {
      // set control text
      ValidateCaptchaButton.Text = "Validate";
      CaptchaCorrectLabel.Text = "Correct!";
      CaptchaIncorrectLabel.Text = "Incorrect!";

      // these messages are shown only after validation
      CaptchaCorrectLabel.Visible = false;
      CaptchaIncorrectLabel.Visible = false;
    }

    if (IsPostBack)
    {
      // validate the Captcha to check we're not dealing with a bot
      bool isHuman = ExampleCaptcha.Validate();

      if (isHuman)
      {
        CaptchaCorrectLabel.Visible = true;
        CaptchaIncorrectLabel.Visible = false;
      }
      else
      {
        CaptchaCorrectLabel.Visible = false;
        CaptchaIncorrectLabel.Visible = true;
      }
    }
  }
}

Web.config

<?xml version="1.0"?>
<!--
  For more information on how to configure your ASP.NET application, please 
  visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
  <appSettings>
    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true"/>
    <add key="ValidationSettings:UnobtrusiveValidationMode" value="None"/>
  </appSettings>
  <system.web>
  <httpHandlers>
    <!-- Register the HttpHandler used for BotDetect Simple API requests -->
    <add verb="GET" path="CaptchaCustomPath.ashx" 
    type="BotDetect.Web.SimpleCaptchaHandler, BotDetect"/>
  </httpHandlers>
  <pages controlRenderingCompatibilityVersion="4.5">
    <controls>
    <!-- Register the BotDetect tag prefix for easier use in all pages -->
    <add assembly="BotDetect" namespace="BotDetect.Web.UI" 
    tagPrefix="BotDetect"/>
    </controls>
  </pages>
  <compilation debug="false" targetFramework="4.5"/>
  <httpRuntime requestValidationMode="4.5" targetFramework="4.5" 
  encoderType="System.Web.Security.AntiXss.AntiXssEncoder, System.Web, Version=4.
  0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>
  <machineKey compatibilityMode="Framework45"/>
  </system.web>
  <system.webServer>
  <validation validateIntegratedModeConfiguration="false"/>
  <handlers>
    <!-- Register the HttpHandler used for BotDetect Simple API requests (IIS 7.0+) -->
    <remove name="BotDetectCaptchaHandler"/>
    <add name="BotDetectCaptchaHandler" preCondition="integratedMode" verb="GET" 
    path="CaptchaCustomPath.ashx" 
    type="BotDetect.Web.SimpleCaptchaHandler, BotDetect"/>
  </handlers>
  </system.webServer>
  
</configuration>

botdetect.xml

<?xml version="1.0" encoding="UTF-8"?>
<botdetect xmlns="https://captcha.com/schema/net"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="https://captcha.com/schema/net 
            https://captcha.com/schema/net/botdetect-4.4.0.xsd">

  <captchaStyles>

    <captchaStyle>
      <!-- Name of captcha style, which is used as a Captcha identifier.
                Valid user Captcha style name allowed setting values are an alphanumeric strings.
            -->
      <name>ExampleCaptcha</name>

      <!-- User input textbox client-side identifier, used for all client-side 
                user input processing, e.g. automatic user input lowercasing and focusing.
                The default value is "CaptchaCode".
                Valid user input ID setting values are path strings, 
                which is value of id attribute of captcha code input textbox.
            -->
      <userInputID>CaptchaCodeTextBox</userInputID>

      <!-- Number of characters in randomly generated Captcha codes 
                (answers to Captcha challenges).
                The default value is random (4-6 characters).
                Valid user Captcha code length setting values are integers larger 
                than 0 and smaller than 16.
                It is recommended to always randomize Captcha code length since it 
                significantly increases Captcha security vs. automated analysis.
            -->
      <codeLength>3-5</codeLength>

      <!-- Character types used to generate random Captcha codes. 
                The default value is Alphanumeric.
                Valid user Captcha code style setting values are string of
                CodeStyle names (Alpha, Numeric, Alphanumeric)
                Since entropy of the Captcha challenge depends on character set size to 
                the power of Captcha code length, alpha codes should be slightly longer 
                than alphanumeric ones (while numeric Captcha codes should be significantly
                longer) to achieve an appropriate level of Captcha security. 
            -->
      <codeStyle>Alpha</codeStyle>

      <!-- Strings that should never occur in randomly generated Captcha codes. Can be 
                both single characters (allows Captcha character set customization) and 
                sequences of two or more characters (useful for swear words filtering, avoiding
                particular hard-to-read sequences etc.).
                The default value is empty (Captcha code filtering is optional).
                Valid user disallowed Captcha code substring setting values are lists of 
                arbitrary strings, in CSV format. Whitespace is ignored, and disallowed 
                substrings are not case-sensitive (because Captcha codes are case-insensitive 
                as well). 
                The character set used for Captcha code generation is automatically chosen 
                based on Captcha locale. Since each character needs to have its pronunciation 
                recorded and available to BotDetect code, expanding that default character set 
                to include new characters is not supported (it would break Captcha sound 
                functionality). However, if a particular character is found hard to read, 
                it can easily be excluded from randomly generated Captcha codes. Furthermore, 
                offensive or otherwise undesirable words and character sequences can be banned.
                Since Captcha codes are generally short, it doesn't make sense to use an 
                actual dictionary of words, but simple short sequences that cover multiple 
                disallowed values. E.g. to prevent the random generator from using both 'man',
                'manners' and 'mannequin' in Captcha codes, it's enough to ban the 'man' 
                sequence.
            -->
      <disallowedCodeSubstrings>d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,aa,bb,cc,abc,bca,cab</disallowedCodeSubstrings>



      <!-- The BotDetect drawing algorithm used to render Captcha codes in image Captcha 
                challenges.
                The default value is random (an image style is chosen from all available 
                values for each Captcha image generated).
                Valid user Captcha image style setting values are CSV strings 
                of names of ImageStyle enumeration members (case-insensitive, separator whitespace is ignored).
                Please note that some image styles are restricted to 
                paid versions of BotDetect, and will be ignored in free version 
                implementations.
                It's best to randomize the Captcha image style, since randomly choosing a 
                style for each Captcha image generated provides the highest level of Captcha 
                security against automated OCR analysis.
            -->
      <imageStyle>Chipped,Fingerprints,Graffiti,Bubbles</imageStyle>

      <!-- Size of Captcha image challenges generated.
                The default value is 250 x 50 pixels.
                Valid user Captcha image size setting values are integers: widths can be 
                between 20 and 500 pixels and heights between 20 and 200 pixels.
                To keep Captcha images reasonably readable, their width:height ratio 
                should be approximately the same as the average Captcha code length.
            -->
      <imageWidth>200</imageWidth>
      <imageHeight>50</imageHeight>

      <!-- Image format in which Captcha images will be generated and sent to the client.
                The default value is JPEG
                Valid user Captcha image format setting values are name of
                ImageFormat enumeration constant (JPEG, PNG, GIF).
                Please note that some Captcha image styles will result in low-quality 
                (pixelated) images when the image format is set to Gif, due to randomized 
                color schemes and use of color gradients. When switching image formats, 
                please take care to check the impact on Captcha image readability.
            -->
      <imageFormat>PNG</imageFormat>

      <!-- BotDetect allows Captcha image color scheme customization though two color 
                points: a custom dark color and a custom light color. 
                The default values are empty (Captcha color customization is optional).
                Valid user Captcha custom dark / light color setting values are Html colors, 
                so you can use both predefined color names and custom color hex values.
                Since many Captcha drawing styles randomize the actual color used, the 
                user-defined values are used as randomization starting points instead of 
                absolute values. Furthermore, since some drawing styles use light text on 
                a dark background, while other draw dark text on a light background, text 
                and background colors are not set directly, but are referred to as simply 
                the "dark" and the "light" color. This allows you to randomize the image 
                drawing style, for example, and still keep a consistent color scheme 
                adjusted to your website design.
            -->
      <customDarkColor>#483d8b</customDarkColor>
      <customLightColor>#87cefa</customLightColor>

      <!--Is Captcha sound enabled.
                The default value is true.
                Valid user Captcha sound enabled setting values are booleans.
                Captcha sound can be disabled entirely (for example if you are using the 
                free version of BotDetect, which only supports demo sound that is not 
                actually accessible to human visitors) by setting this property to false. 
            -->
      <soundEnabled>true</soundEnabled>

      <!-- The BotDetect audio generation algorithm used to pronounce Captcha codes in 
                sound Captcha challenges.
                The default value is random (a sound style is chosen from all available 
                values for each Captcha sound generated).
                Valid user Captcha sound style setting values are CSV strings of
                SoundStyle enumeration constant names (case-insensitive, separator whitespace is ignored).
                Please note that some sound styles are restricted 
                to paid versions of BotDetect, and will be ignored in free version 
                implementations.
                It's best to randomize the Captcha sound style, since randomly choosing a 
                style for each Captcha sound generated provides the highest level of Captcha 
                security against automated audio analysis and voice recognition.
            -->
      <soundStyle>Dispatch,RedAlert,Synth</soundStyle>

      <!-- Audio format in which Captcha sounds will be generated and sent to the client.
                The default value is WAVPCM16BIT8KHZMONO
                Valid user Captcha sound format setting values are name of the  
                SoundFormat enumeration constant (WAVPCM16BIT8KHZMONO, WAVPCM8BIT8KHZMONO).
                Using 8 bit sound instead of default 16 bits per example lowers the WAV file 
                download size, but reduces sound quality.
            -->
      <soundFormat>WAVPCM16BIT8KHZMONO</soundFormat>

      <!-- How will multiple consecutive requests for audio Captcha with the same 
                Captcha code ("sound regeneration") be handled by BotDetect - a tradeoff 
                of security, usability, and storage requirements.
                The default value is LIMITED.
                Valid user Captcha sound regeneration mode setting values are name of
                SoundRegenerationMode enumeration constant (None, LIMITED, UNLIMITED)
                BotDetect defaults to limited sound regeneration as the most reasonable 
                overall trade-off. At user discretion, higher security and usability can be 
                achieved by disabling sound regeneration at the cost of significant amounts 
                of server-side storage space. Unlimited sound regeneration is not recommended 
                due to low security, but is left as an option for backwards-compatibility.
            -->
      <soundRegenerationMode>None</soundRegenerationMode>

      <!-- Captcha locale string, determining the exact character set used for random 
                Captcha code generation and the pronunciation language used for sound 
                Captcha generation.
                The default value is en-US.
                Valid user Captcha locale setting values are composed of ISO language codes 
                (for example en, ru, cmn, ...), charset codes (for example ja-Hira uses 
                Japanese Hiragana characters, while ja-Kana uses Japanese Katakana characters) 
                and country codes (for example en-US and en-GB differ in the pronunciation 
                used).
                Check the BotDetect localization page to find the list of currently supported 
                locales, and download the pronunciation resources required for Captcha sounds.
                If you use a right-to-left locale setting like Arabic or Hebrew, you should 
                also set the appropriate text direction on the textbox element used for 
                Captcha code retyping (dir="rtl").
            -->
      <locale>en-US</locale>

      <!-- The alternative text of the Captcha image Html element.
                The default value is Retype the CAPTCHA code from the image.
                Valid user Captcha image tooltip setting values are arbitrary strings.
            -->
      <imageTooltip>Custom Captcha image tooltip</imageTooltip>

      <!-- Tooltip of the Captcha sound icon.
                The default value is "Speak the CAPTCHA code".
                Valid user Captcha sound tooltip setting values are arbitrary strings.
            -->
      <soundTooltip>Custom Captcha sound icon tooltip</soundTooltip>

      <!-- Tooltip of the Captcha reload icon.
                The default value is "Change the CAPTCHA code".
                Valid user Captcha reload tooltip setting values are arbitrary strings.
            -->
      <reloadTooltip>Custom Captcha reload icon tooltip</reloadTooltip>

      <!-- Text or tooltip of the Captcha help link, depending on help link mode.
                The default value depends on the width of the Captcha image.
                Valid user Captcha help link setting values are strings at least 4 characters 
                long.
            -->
      <helpLinkText>Custom Captcha help link text</helpLinkText>

      <!-- Url of the localized Captcha help page the help link points to.
                The default value depends on Captcha locale.
                Valid user Captcha help link url setting values are absolute or relative Urls.
                This setting is only supported in paid versions of BotDetect.
            -->
      <helpLinkUrl>custom-captcha-help-page.html</helpLinkUrl>

      <!-- Is Captcha reloading (changing the Captcha code because the current one is 
                too hard to read) enabled.
                The default value is true.
                Valid user Captcha reload enabled setting values are booleans.
                Requesting a new Captcha challenge on the current form requires client-side 
                scripting, so the reload icon is only shown in browsers that have JavaScript 
                enabled. When JavaScript is disabled or unsupported, the visitor can still 
                get a different Captcha challenge by reloading the form.
            -->
      <reloadEnabled>false</reloadEnabled>

      <!-- Default BotDetect Captcha icons are 22x22 pixels large, but there is also a 
                smaller set of 17x17 px icons used when the default ones are too large. 
                This settings allows you to control which icon set will be used.
                The default value is true when the Captcha image height is < 50px, and false 
                otherwise.
                Valid user use small Captcha icons setting values are booleans: setting this 
                value to true will force BotDetect to use small built-in icons, while false 
                will disable automatic switching to small icons depending on image height.
                This setting only applies to default BotDetect icons, and should not be used 
                in combination with user-defined icons
            -->
      <useSmallIcons>false</useSmallIcons>

      <!-- BotDetect displays the Captcha sound and reload icon one below the other by 
                default, and switches to displaying them one beside the other when Captcha 
                images are small enough. This setting allows you to control which BotDetect 
                icon layout will be used.
                The default value is true when the Captcha image height is <40px, and false 
                otherwise.
                Valid user use horizontal Captcha icons setting values are booleans: setting 
                this value to true will force BotDetect to use a horizontal icon layout, 
                while false will disable automatic switching to horizontal icons depending 
                on image height.
                This setting only applies to default BotDetect icons, and should not be used 
                in combination with user-defined icons.
            -->
      <useHorizontalIcons>false</useHorizontalIcons>

      <!-- Url of the optional custom Captcha sound icon that will be used instead of 
                the default one.
                The default value is 'botdetectcaptcha?get=sound-icon'.
                Valid user Captcha sound icon setting values are absolute or relative Urls.
                When specifying a custom Captcha sound icon, you should make sure its 
                filename includes "icon", and also provide a disabled variation of the icon 
                that will be shown during sound playback (to prevent the user from clicking 
                the icon multiple times). The disabled sound icon variant should be the same 
                size and have a filename based on the active one ("icon" replaced with 
                "disabled-icon").
            -->
      <soundIconUrl>custom-sound-icon.gif</soundIconUrl>

      <!-- Url of the optional custom Captcha reload icon that will be used instead of 
                the default one.
                The default value is 'botdetectcaptcha?get=reload-icon'.
                Valid user Captcha reload icon setting values are absolute or relative Urls.
                When specifying a custom Captcha reload icon, you should make sure its 
                filename includes "icon", and also provide a disabled variation of the icon 
                that will be shown while the browser is waiting to fetch a new Captcha 
                challenge from the server (to prevent the user from clicking the icon
                multiple times). The disabled reload icon variant should be the same size 
                and have a filename based on the active one ("icon" replaced with 
                "disabled-icon").
            -->
      <reloadIconUrl></reloadIconUrl>

      <!-- Custom width of the Captcha icons div element.
                The default value depends on Captcha image height, since BotDetect will 
                automatically determine default icon size and position to match it.
                Valid user Captcha icons div width setting values are positive integers.
                If your custom Captcha icons are not of the same size as the default 
                BotDetect ones (22x22 px), the UseHorizontalIcons setting won't be able to 
                control the icon layout correctly. You can control whether your custom icons 
                will be displayed one beneath the other or one beside the other by setting 
                an appropriate icons div width: setting it to at least twice the icon width 
                + 8px of padding will result in horizontal icon layout, while smaller values 
                will result in vertical icon layout.
            -->
      <iconsDivWidth>25</iconsDivWidth>

      <!-- Will Captcha markup include a link to a Captcha help page providing Captcha 
                instructions and explanations for form users.
                The default value is true.
                Valid user help link enabled setting values are booleans.
                This setting is only supported in paid versions of BotDetect.
            -->
      <helpLinkEnabled>true</helpLinkEnabled>

      <!-- How will the Captcha help link be displayed.
                The default value is TEXT.
                Valid user Captcha help link mode setting values are name of HelpLinkMode enumeration members ("IMAGE" or "TEXT").
                When using the Image help link mode, Captcha image is wrapped in a link, and 
                clicking it opens the help page in a new browser tab. This mode takes less 
                space, but can lead to accidental clicks (particularly by mobile visitors).
                When using the Text help link mode, Captcha image height is automatically 
                reduced by 10 px and a text link to the Captcha help page is inserted below 
                it. If this makes the Captcha images less readable, you can compensate by 
                increasing the Captcha image height.
            -->
      <helpLinkMode>TEXT</helpLinkMode>

      <!-- User-defined CSS classes that will be added to the BotDetect CAPTCHA 
                container <div>.
                The default value is empty.
                Valid user additional Css classes setting values are strings containing 
                desired class names in standard space-delimited CSS class format.
                CSS style declarations for these custom classes must be defined in a user 
                stylesheet added to the page.
            -->
      <additionalCssClasses>class1 class2 class3</additionalCssClasses>

      <!-- User-defined CSS style declarations that will be added as inline style 
                of the BotDetect CAPTCHA container <div>.
                The default value is empty.
                Valid user additional Css style setting values are strings containing 
                desired CSS style declarations in standard semicolon-delimited CSS style format.
            -->
      <additionalInlineCss>border: 4px solid #fff; background-color: #f8f8f8;</additionalInlineCss>

      <!-- Should the BotDetect JavaScript client-side script code be included by the 
                generated Captcha container markup. 
                The default value is true.
                Valid user add script include setting values are booleans.
                This setting will usually only be set to false if you have multiple Captcha 
                instances on the same form and only want the first one's markup to include 
                the required BotDetect client-side code. Another possible use is when you 
                manually add the necessary <script> include to page <head>, possibly combined 
                with other JavaScript code and minified to reduce the number of Http requests 
                made by the page.
            -->
      <addScriptInclude>true</addScriptInclude>

      <!-- Should the JavaScript code for BotDetect client-side object creation be 
                included in the generated Captcha container markup.
                The default value is true.
                Valid user add init script include setting values are booleans.
                Adding the initialization script fragment should be turned off only if you 
                will manually add the necessary <script> code to form <head> for example.
            -->
      <addInitScriptInclude>true</addInitScriptInclude>

      <!-- Should user Captcha code input be automatically uppercased on the fly.
                The default value is true.
                Valid user auto uppercase input setting values are booleans.
                Since Captcha validation is not and should not be case-sensitive (it would 
                hinder human visitors more than bots, and how would case differences be 
                communicated through audio Captcha in all supported pronunciation languages?), 
                automatically uppercasing user input is a small usability improvement that 
                helps communicate the case-insensitivity of the Captcha challenge to users.
            -->
      <autoUppercaseInput>true</autoUppercaseInput>

      <!-- Should the Captcha code input textbox automatically be assigned focus on 
                all Captcha sound and Captcha reload icon clicks, allowing the users to 
                more easily type in the code as they hear it or as the new image loads. 
                The default value is true.
                Valid user Captcha auto focus input setting values are booleans.
                Automatic input element focusing is not triggered by auto-reloading of 
                expired Captcha challenges, since the user might be filling out another 
                field on the form when the auto-reload starts and shouldn't be distracted.
            -->
      <autoFocusInput>true</autoFocusInput>

      <!-- Should the Captcha user input textbox automatically be cleared on all 
                reload icon clicks and auto-reloads of expired Captcha codes.
                The default value is true.
                Valid user auto clear input setting values are booleans.
                Automatic input clearing is a small usability improvement: since any 
                previous user input will be invalidated by Captcha reloading, it helps so 
                users don't have to delete the previous input themselves.
            -->
      <autoClearInput>true</autoClearInput>

      <!-- Should Captcha challenges automatically be reloaded when the Captcha code 
                expires (controlled by the CodeTimeout property).
                The default value is true.
                Valid user auto reload expired Captchas setting values are booleans.
                Automatic reloading of expired Captcha codes allows you to have a short 
                Captcha code timeout (e.g. 2 minutes) to narrow the window of opportunity 
                for Captcha reusing on other sites or human-solver-powered bots, and actual 
                visitors can still fill out your form at their own pace and without rushing 
                (since the Captcha image will be reloaded automatically when it is no longer 
                valid).
            -->
      <autoReloadExpiredCaptchas>true</autoReloadExpiredCaptchas>

      <!-- Time period in seconds after which automatic reloading of expired Captcha 
                challenges will cease.
                The default value is 7200 seconds (2 hours).
                Valid user auto reload timeout setting values are positive integers.
                This timeout prevents indefinite extension of the visitor Session, when the 
                user leaves the form open in a background browser tab over the weekend for 
                example.
            -->
      <autoReloadTimeout>3600</autoReloadTimeout>

      <!-- Starting delay (in milliseconds) of Captcha audio JavaScript playback.
                The default value is 0 (no delay).
                Valid user Captcha sound start delay setting values are positive integers.
                An initial delay before browser sound playback can be useful for improving 
                usability of the Captcha audio for blind people using JAWS or similar screen 
                readers. Such assistive technology will read the label associated with the 
                Captcha code textbox and start sound playback simultaneously when the sound 
                icon is activated (since Captcha sound playing automatically focuses the 
                Captcha code textbox by default). Setting this delay to e.g. 2000 (2 seconds) 
                will give the user time to hear both the pronounced label and the Captcha 
                sound clearly.
            -->
      <soundStartDelay>1000</soundStartDelay>

      <!-- Should BotDetect also add a remote JavaScript include 
                (remote.captcha.com/include.js) loaded from the captcha.com server (which is 
                currently used only for stats, but is planned to develop into additional 
                Captcha functionality).
                The default value is true.
                Valid user remote script enabled setting values are booleans.
                This setting is only supported in paid versions of BotDetct.
            -->
      <remoteScriptEnabled>false</remoteScriptEnabled>
    </captchaStyle>

  </captchaStyles>


  <!-- Path of the BotDetect SimpleCaptchaServlet used for processing Captcha image, 
        sound and Ajax validation requests, as well as accessing all BotDetect 
        public resources (Captcha icons, layout stylesheet, client-script include).
        The default value is "/botdetectcaptcha".
        Valid user Captcha SimpleCaptchaHandler request path setting values are path strings, 
        which must also be used in application registration of the BotDetect SimpleCaptchaHandler (Web.config).
    -->
  <servletRequestPath>CaptchaCustomPath.ashx</servletRequestPath>

  <!-- The time period after random Captcha code generation during which Captcha 
        challenges based on it can be solved: when it expires, even correct inputs 
        will be considered as invalid submissions.
        The default value is 1200 seconds (20 minutes).
        Valid user Captcha code timeout setting values are integers larger than 30 
        and smaller than 7200 (i.e. between half a minute and 2 hours). 
        Reducing the Captcha code timeout is an optional security improvement that
        narrows the window of opportunity for attacks based on reusing the Captcha 
        challenge on another site controlled by the attacker, proxying it to human 
        solvers, or similar attempts to bypass the Captcha protection. However, to 
        meet usability criteria, users filling out the form should always be given 
        reasonably enough time to solve the Captcha challenge. Since Captcha codes 
        are stored in Session state by default, please note that if the configured 
        code timeout is longer than the active Session timeout, Captcha validation 
        will still fail if the user Session expires due to inactivity.
    -->
  <codeTimeout>600</codeTimeout>

  <!-- Application configuration switch to use if you want to run automated tests 
        that need to be able to submit a Captcha-protected form in QA environments.
        The default value is false.
        Valid user Captcha test mode setting values are booleans.
        When test mode is enabled, it makes the Captcha challenge trivially solvable 
        (always using "TEST" as the solution instead of a random sequence of 
        characters). Be careful NEVER to enable this on production websites by 
        mistake, since it will allow bots to trivially bypass the Captcha, but will 
        still provide an obstacle for human users. Because of the serious security 
        implications if the Captcha test mode setting is misapplied, it can only be 
        enabled globally for the whole application (individual forms and Captcha 
        object instances can't change it), and will display a warning in generated 
        Captcha container markup.
        This setting is only supported in paid versions of BotDetect.
    -->
  <testModeEnabled>false</testModeEnabled>

  <!-- Application configuration setting that allows centralized temporary 
        disabling of individual BotDetect image styles if there is ever an urgent 
        issue that requires it. 
        The default value is empty (image style disabling is an optional feature 
        meant for short-term use during exceptional situations).
        Valid user disabled image styles setting values are CSV strings of ImageStyle 
        enumeration constant names (case-insensitive, separator whitespace is ignored).
        BotDetect image styles used on user forms can be configured in different ways 
        (a single static value, a randomized value, a dynamic value that adapts to 
        visitor behavior) and can apply to all Captcha instances in an application 
        or be specific to a particular Captcha challenge placed on a single form. If 
        an urgent issue is ever discovered in a BotDetect image style implementation 
        (e.g. a bug causing it to throw errors in certain circumstances, or a 
        weakness allowing some forms of automated analysis to bypass it, or a 
        memory leak etc.), users should be able to deactivate the problematic 
        ImageStyle while they're waiting for issue resolution. This BotDetect 
        setting acts as a centralized application configuration switch which allows 
        such image style deactivation, without requiring users to examine and 
        possibly modify all of their source code that might be affected. It also 
        makes it much easier to revert the change later when the issue gets fixed.
    -->
  <disabledImageStyles>Chipped,Lego,Wave</disabledImageStyles>

  <!-- Application configuration setting that allows centralized temporary 
        disabling of individual BotDetect sound styles if there is ever an urgent 
        issue that requires it. 
        The default value is empty (sound style disabling is an optional feature 
        meant for short-term use during exceptional situations).
        Valid user disabled sound styles setting values are CSV strings of SoundStyle 
        enumeration constant names (case-insensitive, separator whitespace is ignored).
        BotDetect sound styles used on user forms can be configured in different ways 
        (a single static value, a randomized value, a dynamic value that adapts to 
        visitor behavior) and can apply to all Captcha instances in an application 
        or be specific to a particular Captcha challenge placed on a single form. If 
        an urgent issue is ever discovered in a BotDetect sound style implementation 
        (e.g. a bug causing it to throw errors in certain circumstances, or a 
        weakness allowing some forms of automated analysis to bypass it, or a 
        memory leak etc.), users should be able to deactivate the problematic 
        SoundStyle while they're waiting for issue resolution. This BotDetect 
        setting acts as a centralized application configuration switch which allows 
        such sound style deactivation, without requiring users to examine and 
        possibly modify all of their source code that might be affected. It also 
        makes it much easier to revert the change later when the issue gets fixed.
    -->
  <disabledSoundStyles>RedAlert,HiveMind</disabledSoundStyles>

  <!-- Application configuration setting controlling the file system location 
        of BotDetect sound resources required for Captcha audio.
        The default value is the Bin\BotDetectSounds subfolder in your ASP.NET 
        application folder.
        Valid user Captcha sound packages folder setting values are absolute file system paths 
        (starting with a drive identifier e,g, "C:\"), network paths (starting with "\"),
        or relative paths based on the application root folder (starting with "~\"))
        You should also always ensure that the web server worker process running your ASP.NET application has permissions to read from the custom folder path.
    -->
  <soundPackagesFolder>C:\Program Files (x86)\Captcha Inc\BotDetect 4 CAPTCHA Component\Asp.Net\BotDetectSounds</soundPackagesFolder>

  <!-- Application configuration setting that controls whether BotDetect disables 
        (greys-out and prevents clicks on) the Captcha sound icon and displays a 
        warning tooltip when the sound package file containing character 
        pronunciations for the currently set Captcha locale can not be found.
        The default value is true (display a warning when the required .bdsp file 
        cannot be found).
        Valid user warn about missing sound packages setting values are booleans.
        Warnings about missing sound packages help during development and deployment, 
        so you don't mistakenly forget to download and copy the needed files. 
        However, this warning is not meant for (and should never be seen by) site 
        visitors. So if you didn't copy a particular sound package because you 
        intentionally don't want to support audio Captcha sounds in that language, 
        you can disable the warning (and the sound icon for such locales).
    -->
  <warnAboutMissingSoundPackages>false</warnAboutMissingSoundPackages>

  <!-- How many repeated Captcha HttpServlet requests using the exact same query 
        string will be allowed in a short time period.
        The default value is 15.
        Valid user Captcha request filter repeated requests allowed setting values 
        are positive integers between 1 and 100.
        You will typically only increase this value if the Captcha request filter is 
        for some reason causing issues with legitimate user behavior in your application.
    -->
  <requestFilterRepeatedRequestsAllowed>5</requestFilterRepeatedRequestsAllowed>

  <httpHandlerRequestPath>CaptchaCustomPath.ashx</httpHandlerRequestPath>

</botdetect> 

In botdetect.xml, we configure captcha options for the ExampleCaptcha captcha style name. You can find a full list of available Captcha configuration options and related instructions at the Captcha configuration options page .


Current BotDetect Versions