BotDetect ASP.NET CAPTCHA Release Notes

documentation > asp.net captcha

This is the version history of the BotDetect ASP.NET Captcha control:

v3.0.9 Released 2011–11–21v3.0.9 migration guide

Fixed a bug with the CustomSessionIdManager throwing FormatExceptions when the Captcha request querystring is malformed by faulty clients
Fixed a bug with Captcha image reloading occasionally throwing JavaScript errors in IE 8 when mousing over the Captcha image while it's reloading
Improved Captcha image security: if no image style is set, randomize the image style for each generated Captcha image (instead of using Chalkboard by default)
Improved Captcha image readability: tweaked most image styles to produce easier to read Captcha images
Added a BotDetect trademark to Captcha images generated by the Free version of the component
Improved Captcha sound security: if no sound style is set, randomize the sound style for each generated Captcha sound (instead of using Dispatch by default)

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v3.0.8 Released 2011–08–15v3.0.8 migration guide

Fixed a bug with CaptchaId generation causing JavaScript errors when Page.AppRelativeVirtualPath starts with a number
Improved CustomSessionIdManager performance under heavy load
Added a workaround for the GbPlugin known issue causing Captcha validation issues for Brazilian visitors (http://captcha.biz/doc/aspnet/known-issues.html#gbplugin)
Improved Captcha image generation: slightly reduced PaintMess and Radar contrast

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v3.0.7 Released 2011–06–13v3.0.7 migration guide

Fixed a bug with security exceptions occurring when trying to play Captcha sounds from Bin folder deployed sound packages in Medium Trust (ASP.NET 4.0 only)
Fixed a bug with the Captcha control CssClass property value not being added to the generated Captcha markup
Improved BotDetect SessionTroubleshooting and HttpHandlerTroubleshooting: replaced Application State persistence with static fields, added several fall-back mechanisms to make troubleshooting more reliable
Improved BotDetect Captcha markup generation: the BotDetect stylesheet include is now placed before the first <link> or <style> element in the page <head>, instead of at the top (where it was interfering with elements that need to be placed first, such as the X-UA-Compatible meta tag)
Improved BotDetect Captcha markup generation: the &s parameter is not added to Captcha image and sound Urls when the BotDetect CustomSessionIdManager is not used
Improved BotDetect Captcha persistence: reduced the size of Session State used for Captcha data in certain scenarios (non-default Captcha locale, StateServer or SQLServer Session State modes)
Improved the Captcha Code Filtering Sample: updated the sample project explanation and simplified all three banned sequence declaration sources to contain the same banned sequences

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v3.0.6 Released 2011–05–18v3.0.6 migration guide

Added support for Captcha protection of ASP.NET MVC 3.0 Razor Views
Improved general ASP.NET MVC compatibility, simplifying the ASP.NET MVC Captcha integration procedure
Improved installed ASP.NET MVC Captcha code samples: ASP.NET MVC 3.0 & 2.0 samples running on .NET 4.0 and ASP.NET MVC 2.0 & 1.0 samples running on .NET 3.5
Fixed a bug with embedded resource access exceptions when server time is set before the assembly modification date
Fixed a bug with Captcha image size and certain other settings not affecting ASP.NET Web Form markup properly when assigned in InitializedCaptchaControl handlers: moved the InitializedCaptchaControl custom event handler execution to the Page_PreRender phase of the ASP.NET Web Forms lifecycle, so custom handlers registered in earlier phases are always fired as expected
Added support for Captcha tabindex setting through the TabIndex control property
Fixed some minor inconsistencies between the ASP.NET 4.0 and ASP.NET 2.0 Captcha control implementations
Improved the BotDetect setup package, so minor updates automatically remove older versions (and don't require manually uninstalling the older version)

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v3.0.5 Released 2011–05–02v3.0.5 migration guide

Fixed a bug with incorrect sound package permissions when using BotDetect from the GAC in ASP.NET applications running in Medium and Minimal Trust
Fixed a bug with the CaptchaRequestValidator consuming HttpCache persistence even when it's turned off
Fixed a bug in the Polish locale-specific character set and pronunciation sound package: replaced 'V' with 'W'
Added the OnHelpLinkClick custom BotDetect client-side event
Added the <captchaHttpHandlerTroubleshooting> BotDetect configuration element allowing BotDetect HttpHandler troubleshooting to be turned off
Updated all default character set definitions to reduce chance of character confusion: removed '7' easily confused with '1' from all CodeStyle.Alpha and CodeStyle.Alphanumeric Captcha codes

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v3.0.4 Released 2011–04–11v3.0.4 migration guide

Fixed a bug with the Lego Captcha image style placing the most noise over the last character
Improved Captcha sound reliability by falling back to an assembly-embedded sound package for the default "en-US" locale if it's not present in the configured sound packages folder
Improved BotDetect sound package folder configuration, now accepting BotDetect assembly-relative folder paths (starting with "\", e.g. "\BotDetectSounds"), ASP.NET application-relative folder paths (starting with "~/", e.g. "~/BotDetectSounds") and network shares (starting with "\\" e.g. "\\SERVER\BotDetectSounds")
Improved BotDetect Url configuration, now also accepting application-relative paths (starting with "~/", e.g. "~/BotDetectCaptcha.ashx" will make BotDetect use server-relative application root paths in generated markup)

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v3.0.3 Released 2011–03–28v3.0.3 migration guide

Fixed a bug with Captcha persistence using StateServer and SQLServer Session state modes being unable to persist custom Captcha locales or colors
Fixed a bug with Captcha drawing code sometimes not placing random noise properly
Improved Captcha image security, scaling, performance and readability (tweaked all 50 existing Captcha image styles)
Added 10 new Captcha image styles: Bubbles, Electric, MeltingHeat2, Neon, Neon2, Radar, Ripple, Ripple2, SpiderWeb2, Split2
Updated font declarations for East Asian locales, using bold fonts by default to make Captcha images easier to read
Updated the default Han Simplified and Han Traditional character set definitions: removed the 纟(0x7E9F, "silk") character from Captcha codes, since it isn't pronounceable
The Captcha Reload button is now placed above the Captcha sound button, and only displayed if JavaScript is enabled (since it's JavaScript-dependent)
The BotDetect client-side initialization script is now executed before window.load if possible (when the page DOM is ready)
Added client ids to all relevant Captcha Html elements for easier custom scripting and styling, and changed Css class names and declarations a bit to keep them consistent
Updated the Captcha layout code to allow greater flexibility through new Captcha object properties (UseHorizontalIcons, UseSmallIcons, and CaptchaIconsDivWidth) and BotDetect configuration elements (added the iconWidth attribute to custom <reloadIcon> and <soundIcon> declarations)
updated the IgnoreRoute statements in ASP.NET MVC code samples to ignore all BotDetect requests regardless of Area, Controller or View paths preceding them

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v3.0.2 Released 2011–02–01v3.0.2 migration guide

Fixed a bug with the Captcha code generation occasionally using less than the full available character set for random code generation
Fixed a bug in the BotDetect Sound Package processing code, which was incorrectly naming .bdsp files for locales with only the macrolanguage set
Improved sound Captcha clarity when using various newly available localized pronunciations: tweaked the Radio, Robot and Synth sound generation algorithms
Updated the default Cyrillic character set definition to reduce chance of character confusion: removed 'З' (Ze) and '3' (three) from alphanumeric Captcha codes

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v3.0.1 Released 2011–01–17v3.0.1 migration guide

Fixed a bug in the BotDetect client-side script include: the BotDetect.Init() function is now only called when the Captcha image is actually rendered on the page
Fixed a bug in BotDetect audio processing code involving Math.Abs(-32768) edge case exceptions
Updated BotDetect pronunciation sound packages for Canadian French and Mexican Spanish
Updated default Latin character set definitions to reduce chance of character confusion with the 3.0 drawing changes (removed 'F' sometimes confused with 'E', 'G' confused with 'C', 'Q' confused with 'O', 'Z' confused with '2' and '7' confused with '1')
Updated locale-specific default character set variants: removed 'W' and 'Z' for the Vietnamese locale
Added a link to the BotDetect localization downloads page in the BotDetect Start Menu folder

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v3.0.0 Released 2010–12–13v3.0.0 migration guideWhat's new in 3.0

Added multi-language Captcha code generation & validation, supporting various Unicode character sets and RTL languages (charsets: Latin, Cyrillic, Greek, Hebrew, Arabic, Devanagari, Han Simplified, Han Traditional, Hangul, Bopomofo, Hiragana and Katakana)
Added Captcha code character set customization options, using a user-defined character set for random Captcha code generation
Added Captcha code filtering, allowing randomly generated Captcha codes to be checked against a user-defined list of banned character sequences
Added Captcha code timeouts, so the Captcha can only be successfully solved within the specified time period after generation
Added test mode support for automated testing scenarios, exposing a configuration switch that causes 100% of Captcha codes generated to be "TEST"
Improved Captcha image security against bots (added more segmentation challenges and randomness to all 50 BotDetect Captcha image styles)
Improved Captcha image readability for humans (the text is larger, visual appearance is improved, there are less distortion challenges in all image styles)
Added Captcha image color scheme customization options, where two user-defined colors can be used to adjust the Captcha color scheme to suit any website design
Improved Captcha sound security, using 10 different sound styles with various effects, noises and randomizations (sound styles: Dispatch, HiveMind, Industrial, Pulse, Radio, RedAlert, Robot, Scratched, Synth, Workshop)
Added multi-language Captcha sound generation, using individual language sound packages downloadable separately from the main control
Improved Captcha sound compatibility, automatically using the HTML5 <audio> element in supporting browsers
Added a new sound format option (WavPcm8bit8kHzMono), resulting in smaller sound file downloads but reducing sound quality
HTML improvements: added customizable Captcha image, sound and reload titles, icons and urls; added automatic Captcha icon scaling to match the Captcha image height; improved client script and stylesheet include robustness
Client-side improvements: added customizable automatic user input lowercasing, textbox focusing on reload and sound Captcha icon clicks, automatic image reloading on Captcha code timeouts, and built-it Ajax validation support
Configuration improvement: added a custom <botDetect> configuration section, allowing detailed BotDetect customization using web.config settings
Persistence improvements: added a Session issue troubleshooting helper
Troubleshooting improvements: added optional detailed debug/trace logging and easy logging provider customization
Added new sample projects (ASP.NET Membership integration, Captcha code filtering option, Captcha customization options) and demonstration forms (BotDetect image styles demo) demonstrating new v3.0 functionality
Improved all web application descriptions, navigation and IIS compatibility
Improved setup experience, with only one setup package for all .NET versions
Added binary package downloads for machines where running the setup package is not feasible
Added ASP.NET 4.0 & Visual Studio 2010 compatibility
Added ASP.NET MVC 2.0 compatibility

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v2.0.15 Released 2009–11–23 v2.0.15 migration guide

Fixed a bug with the CAPTCHA image failing to render on some servers even when the CaptchaHandler is properly registered
Fixed a bug with the Captcha control breaking on shared servers (running in Medium Trust)
Fixed a bug with the CAPTCHA event registration occasionally throwing "key already exists" exceptions during concurrent page access (implemented proper global event locking)
Fixed a bug with the CAPTCHA Troubleshooting code samples not working properly on IIS 7.5 / Windows Server 2008 R2 and Windows 7 (the InstallSamples.bat script now also grants log file write access to the appropriate ApplicationPoolIdentity user)
Added a X-Robots-Tag Http header to CAPTCHA image and sound Http responses that prevents search engine indexing of CAPTCHA images and sounds
Improved handling of invalid CAPTCHA Http requests (basic problem identification)

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v2.0.14 Released 2009–09–14 v2.0.14 migration guide

Fixed a bug with CAPTCHA validation failing inside UpdatePanel variants in Telerik and other non-Microsoft Ajax frameworks
Fixed a bug with CAPTCHA client-side scripts not working when the Captcha control is not visible on the first page load, but gets added after a partial postback
Fixed a bug causing key conflicts with applications or other components using Rick Strahl's ClientScriptProxy
Fixed a bug allowing direct access to sound CAPTCHAs even if the Captcha.SoundEnabled property is set to false
Fixed a bug with the BotDetect layout stylesheet not overriding other, possibly conflicting CSS declarations included on the page
Improved validation of CAPTCHA image and sound request querystring parameters, rejecting a wider variety of automated requests sent by some bots
Improved the BotDetect Troubleshooting utility and sample projects, allowing users to also log all CAPTCHA validation attempts
Improved usability of the progress indicator for CAPTCHA image reloading, using a locale-independent animation
Improved flexibility of CAPTCHA image reloading by adding custom PreReloadCaptchaImage and PostReloadCaptchaImage client-side events that can be handled by user code
Improved usability of all BotDetect sample projects by automatically clearing the CAPTCHA code user input after clicking the Reload CAPTCHA button
Improved the ASP.NET MVC CAPTCHA sample projects, using a custom ActionFilterAttribute for CAPTCHA validation
Separated ASP.NET Ajax sample projects for .NET Framework versions 2.0 and 3.5
Marked the Lanap.BotDetect.dll assembly as CLS-Compliant

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v2.0.13 Released 2009–02–02 v2.0.13 migration guide

Added ASP.NET MVC RC1 support and ASP.NET MVC RC1 CAPTCHA code samples (C# BotDetect ASP.NET MVC Demo and VB.NET BotDetect ASP.NET MVC Demo)
Fixed a bug with the PreDrawCaptchaImage handler being re-registered and executed multiple times (the number cumulatively increasing for every page load)
Fixed a bug with multiple randomized CAPTCHA controls in the application all using the last registered PreDrawCaptchaImage handler instead of the appropriate one
Fixed a bug with the CAPTCHA CodeLength and CodeType not being randomized on the first page load
Fixed a bug with the CAPTCHA validation failing when there is an ASP.NET Ajax UpdatePanel on the page, but the Captcha control is not within it
Fixed a bug with the CAPTCHA sound and reload buttons not being focusable using the keyboard
Fixed a bug with the audio CAPTCHA not playing in IE when using SSL offloading (added client-side SSL detection)
Fixed a bug with the CustomSessionIDManager exposing the ASP.NET SessionID in plaintext
Fixed a bug with multiple CAPTCHA control instances on the same page and CAPTCHA CSS declarations (changed all BotDetect CSS declarations to use CSS classes instead of ids)
Fixed a bug with the CAPTCHA Troubleshooting code samples not registering the ErrorTrackingModule when using IIS 7.0 Integrated Mode
Added a missing </div> to the ASP.NET Ajax CAPTCHA code samples

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v2.0.12 Released 2008–07–03 v2.0.12 migration guide

Fixed a bug with the audio CAPTCHA not playing in IE when using SSL
Fixed a bug with the audio CAPTCHA not playing in Opera 9.5
Fixed a bug with the CAPTCHA image not displaying when the IIS virtual folder name contains spaces
Fixed a bug with the CAPTCHA validation always returning false for all validation attempts after the first one when placed inside a Telerik RadAjaxPanel
Fixed a bug with the sample projects not displaying the CAPTCHA image when using IIS 7.0 Integrated Mode

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v2.0.11 Released 2008–05–29 v2.0.11 migration guide

Fixed a bug with the CAPTCHA randomization being bypassed when clicking the Reload CAPTCHA button, or for other direct CAPTCHA image requests
Fixed a bug with the sequential Reload CAPTCHA button clicks appending new values to the querystring instead of replacing the existing one
Fixed a bug with the CAPTCHA stylesheet not resetting link styles for the Reload and Sound CAPTCHA buttons, causing layout problems if the page link style includes padding etc.
Fixed a bug with the CAPTCHA validation always failing if the .aspx form path includes spaces or other Url-encoded characters
Fixed a client-side script include bug occurring when a Captcha control is placed inside a MultiView control which is inside an ASP.NET Ajax UpdatePanel
Added support for CAPTCHA image and sound request full path customization (instead of just the extension) via web.config settings
Improved handling of invalid CAPTCHA requests sent by some bots (repeated CAPTCHA image or sound requests with expired parameters)

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v2.0.10 Released 2008–04–06 v2.0.10 migration guide

Added "Reload CAPTCHA" button support (allowing users to request a new CAPTCHA code if the current one is unreadable), and the related ReloadEnabled property
Added ASP.NET Ajax built-in compatibility, allowing the "out of the box" Captcha control to validate inside an UpdatePanel
Added built-in SharePoint support (previous versions required source code modifications)
Added support for CAPTCHA image and sound request extension customization via web.config settings
Added a static variant of the Validate() method, allowing easier integration with various Ajax and MVC frameworks
Rewrote the Captcha control rendering code to produce smaller, semantic, XHTML 1.1 Strict compliant markup
Added 3 new Captcha control properties: SoundIconAltText, ReloadIconAltText and CaptchaImageAltText, allowing HTML output string customization
Improved handling of invalid CAPTCHA requests sent by some bots (with &amp;amp;-style constructs in the querystring)
Fixed a bug with the sample projects not performing CAPTCHA validation in IE 6.0 & 7.0 when typing in the CAPTCHA code and pressing Enter
Improved the usability of all samples by automatically lowercasing the CAPTCHA code input while typing
Added a "Simulate Error" button and related instructions to the Troubleshooting sample CAPTCHA projects
Packaged the updated version of the web.config file with the MS Ajax samples, allowing .NET 3.5 machines to use them without running the Visual Studio 2008 Conversion Wizard

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v2.0.9 Released 2008–02–06

Minor ASP.NET 2.0 Ajax CAPTCHA samples code cleanup
Some cosmetic changes in existing CAPTCHA text styles

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v2.0.8 Released 2007–10–21

Fixed a bug with the CAPTCHA code timeout being set to 20 min even if the Session timeout is longer
Fixed a bug with multiple CAPTCHAs on the same page and only being able to validate the first one
Fixed a bug causing exceptions to be thrown while processing invalid CAPTCHA image/sound requests used by some bots
Fixed the CAPTCHA control's XHTML output to be WCAG AAA compliant

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v2.0.7 Released 2007–07–18

Fixed a bug with the audio CAPTCHA in IE 7.0 / Vista / Media Player 11 (.NET 2.0 version only)
Fixed a bug with the audio CAPTCHA in older versions of IE when using SSL
Fixed the CAPTCHA image and sound links to be XHTML compliant

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v2.0.6 Released 2007–07–02

Fixed a bug causing errors when using the “Sql” and “StateServer” Session State modes (marked the CaptchaCode class as Serializable)
Improved control extensibility (changed useful Captcha class fields and methods from private to protected)
Improved all samples to also work with disabled cookies (.NET 2.0 version only)
Added basic MS ASP.NET 2.0 Ajax Extensions samples (C# and VB.NET) to the installation (.NET 2.0 version only)
Added the “log4net.dll” assembly to the “Troubleshooting” installation folder, which was omitted by error in the previous release (.NET 1.1 version only)

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v2.0.5 Released 2007–03–20

Fixed a bug with the component sometimes throwing exceptions on the Visual Studio design surface

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v2.0.4 Released 2007–03–13

Fixed a bug with the sound link both playing the sound in the background and opening the download dialog in Firefox (.NET 1.1 version only)

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v2.0.3 Released 2007–03–02

Fixed a bug preventing detailed error logging (accidentally deleting inner exception data)
Added a centralized, non-intrusive, BotDetect-only, highly customizable error logging utility
Fixed a bug with "object reference not set…" errors for BotDetect properties in the Visual Studio designer
Fixed a bug displaying the same image and/or breaking validation when using multiple CAPTCHAs per page
Fixed a bug breaking validation with the same page (containing CAPTCHA) opened in multiple browser tabs
Fixed a bug allowing the same code to be used to draw multiple images if both validation and page reloading were skipped
Fixed a bug displaying the same CAPTCHA (but breaking validation) when using the Back button in IE
Fixed a bug with the sound CAPTCHA not working without Javascript
Fixed a bug with the sound CAPTCHA not working in Safari
Fixed a bug with the CAPTCHA image not changing after first load in Opera
Fixed a bug in the uninstallation script occurring on machines without IIS
Fixed a bug in the installation script for ASP.NET not setting the correct runtime version when multiple .NET framework versions are installed
Added a new sample demonstrating CAPTCHA randomization
Added a new sample demonstrating CAPTCHA troubleshooting
Updated and expanded the Help

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v2.0.2 Released 2006–06–25

Updated licensing information packaged in the setup

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v2.0.1 Released 2006–06–18What's new in 2.0

Added sound CAPTCHA support
Added 10 new CAPTCHA text styles (for a total of 50 different CAPTCHA algorithms)
Improved memory management
Added shared server support
Fixed a CAPTCHA vulnerability allowing the user to bypass the CAPTCHA entirely by replaying a previous ViewState parameter value
Stopped using client side (ViewState) persistence altogether
Added a VB.NET sample demonstrating dynamic setting of all CAPTCHA properties
Fixed a bug preventing ASP.NET 1.1. and ASP.NET 2.0 versions from coexisting on the same machine

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v1.5.3 Released 2005–08–13

Added support for ASP.NET 2.0 (.NET framework 2.0)
Added 21 new CAPTCHA text styles (for a total of 40 different CAPTCHA algorithms)
Some cosmetic changes in existing CAPTCHA text styles

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