Comments on: How To Create a CAPTCHA Graphic in VB.NET http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/ Articles on VB.NET and Software Development Team Leadership Wed, 20 Aug 2008 12:02:07 +0000 http://wordpress.org/?v=2.2.2 By: Cathy http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1166 Cathy Mon, 21 Jul 2008 06:07:25 +0000 http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1166 Hi, I would like to know the design part of the code.. i.e.captcha Hi,

I would like to know the design part of the code.. i.e.captcha

]]> By: jfrankcarr http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1093 jfrankcarr Wed, 23 Apr 2008 18:50:26 +0000 http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1093 Hi Chuck, That is true. However, there are some blackhat scripts around that I've seen that will do some equation solving for captchas, particularly if it's worded like you have in your comment. It's a never ending battle against spam. While I don't update this site often due to other commitments, I do keep an eye on it. In the past 3 months there have been over 10000 spam comment attempts. Akismet, while not perfect, does a good job of keeping them at bay. Hi Chuck,

That is true. However, there are some blackhat scripts around that I’ve seen that will do some equation solving for captchas, particularly if it’s worded like you have in your comment.

It’s a never ending battle against spam. While I don’t update this site often due to other commitments, I do keep an eye on it. In the past 3 months there have been over 10000 spam comment attempts. Akismet, while not perfect, does a good job of keeping them at bay.

]]> By: Chuck http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1092 Chuck Wed, 23 Apr 2008 17:46:39 +0000 http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1092 Sometime even more effective than captcha is just asking a simple, easy for humans to understand, hard for computers to grasp, question. Something as simple as "What is the sum of 10 and 5?" As far as I know, there are no bots out there yet smart enough to decipher such simple questions. A more sophisticated system could randomize a set of simple questions, to make it even more secure. What color is the sun? Yellow. What is the name of the planet on which we live? Earth and so on. Another advantage is this is more accessible to the vision-impaired. Sometime even more effective than captcha is just asking a simple, easy for humans to understand, hard for computers to grasp, question.

Something as simple as “What is the sum of 10 and 5?”

As far as I know, there are no bots out there yet smart enough to decipher such simple questions. A more sophisticated system could randomize a set of simple questions, to make it even more secure.

What color is the sun? Yellow.
What is the name of the planet on which we live? Earth

and so on.

Another advantage is this is more accessible to the vision-impaired.

]]> By: Sanjai Malani http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1059 Sanjai Malani Tue, 08 Apr 2008 06:37:57 +0000 http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1059 How do you call this class and use it in the page? How do you call this class and use it in the page?

]]> By: Yoko http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1017 Yoko Sun, 09 Mar 2008 03:39:42 +0000 http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1017 Very informative. Thanks for sharing. :) Very informative. Thanks for sharing. :)

]]> By: David http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1012 David Wed, 27 Feb 2008 00:04:37 +0000 http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1012 How do you call this class and use it in the page? How do you call this class and use it in the page?

]]> By: Keith B. http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1006 Keith B. Wed, 13 Feb 2008 20:21:35 +0000 http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-1006 Thanks for the code download and the tips. Nice post. Thanks for the code download and the tips. Nice post.

]]> By: Will N http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-983 Will N Thu, 17 Jan 2008 16:49:34 +0000 http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-983 How do you call this on your page to show the image? How do you call this on your page to show the image?

]]> By: jfrankcarr http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-930 jfrankcarr Sun, 18 Nov 2007 17:48:31 +0000 http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-930 Hi Naafraat, That would require Optical Character Reader (OCR) software. There are several tools available for .NET that can do this to varying degrees of success. How well it will decipher a CAPTCHA depends on the how hard the graphic is to read. In my example, the background grid graphic, random placement, font and dots would make it more difficult to OCR than plain text. If you applied more effects to the graphic it would make it more difficult to read, both for software and humans. Hi Naafraat,

That would require Optical Character Reader (OCR) software. There are several tools available for .NET that can do this to varying degrees of success.

How well it will decipher a CAPTCHA depends on the how hard the graphic is to read. In my example, the background grid graphic, random placement, font and dots would make it more difficult to OCR than plain text. If you applied more effects to the graphic it would make it more difficult to read, both for software and humans.

]]> By: Naafraat http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-928 Naafraat Sun, 18 Nov 2007 11:27:02 +0000 http://vbnotebookfor.net/2007/11/06/how-to-create-a-captcha-graphic-in-vbnet/#comment-928 I have seen some software tools that can read a Captcha graphic. How is that made possible. Can we do it using vb ? I have seen some software tools that can read a Captcha graphic. How is that made possible. Can we do it using vb ?

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