Comments on: Why does google use CAPTCHA? http://alastairc.ac/2006/12/why-does-google-use-captcha/ Kything web interactions Mon, 21 Jun 2010 21:13:28 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: ShaQ http://alastairc.ac/2006/12/why-does-google-use-captcha/comment-page-1/#comment-124688 ShaQ Wed, 18 Feb 2009 22:09:44 +0000 http://alastairc.ac/2006/12/why-does-google-use-captcha/#comment-124688 With Experience with Blocking spam, using these other methods that you mention are too restrictive and flag False Positives (Positives being Spam). Web presences like Microsoft, Google, Yahoo, Alta-Vista cannot risk blocking out a SINGLE valid user in the name of blocking out ALL spam. In Programming Languages/Type Inference, The solution needs to be Complete but need not be Sound. It has been proven that you CANNOT (At least Very Difficult) have a Sound solution, that is ALSO complete. For Large Scale problems like this. With Experience with Blocking spam, using these other methods that you mention are too restrictive and flag False Positives (Positives being Spam). Web presences like Microsoft, Google, Yahoo, Alta-Vista cannot risk blocking out a SINGLE valid user in the name of blocking out ALL spam.

In Programming Languages/Type Inference, The solution needs to be Complete but need not be Sound. It has been proven that you CANNOT (At least Very Difficult) have a Sound solution, that is ALSO complete. For Large Scale problems like this.

]]> By: AlastairC http://alastairc.ac/2006/12/why-does-google-use-captcha/comment-page-1/#comment-107828 AlastairC Sun, 16 Nov 2008 18:51:44 +0000 http://alastairc.ac/2006/12/why-does-google-use-captcha/#comment-107828 Hi Hamid, I don't think you quite understood, I wasn't saying anything about their search. Google actually does block robot style behaviour on their search, but with an error page based on your IP address rather than a CAPTCHA. Hi Hamid,

I don’t think you quite understood, I wasn’t saying anything about their search.

Google actually does block robot style behaviour on their search, but with an error page based on your IP address rather than a CAPTCHA.

]]> By: hamid http://alastairc.ac/2006/12/why-does-google-use-captcha/comment-page-1/#comment-107612 hamid Sat, 15 Nov 2008 17:26:29 +0000 http://alastairc.ac/2006/12/why-does-google-use-captcha/#comment-107612 I dont think that using Akismet like system on Google Search back end would be a better option. Let me explain, Just have a look around, and evey at your searching pattern and what you search, most of the searches on google appear to be spam. For example: a nob may search 'Hello World', or his website name, or its own name etc. Similar is the case when a person tries to search a phrase that seem just like a Spam phrase but in actual its not span or BOT. He just need it, and if Google block him, Google will loose 1 user. I dont think that using Akismet like system on Google Search back end would be a better option.

Let me explain,
Just have a look around, and evey at your searching pattern and what you search, most of the searches on google appear to be spam. For example: a nob may search ‘Hello World’, or his website name, or its own name etc.

Similar is the case when a person tries to search a phrase that seem just like a Spam phrase but in actual its not span or BOT. He just need it, and if Google block him, Google will loose 1 user.

]]> By: Scott Gray http://alastairc.ac/2006/12/why-does-google-use-captcha/comment-page-1/#comment-103994 Scott Gray Thu, 30 Oct 2008 14:27:07 +0000 http://alastairc.ac/2006/12/why-does-google-use-captcha/#comment-103994 Instead of captcha, what about something like the following, which is quick and easy, and hard for a bot to get past... To Continue Answer the following: Bob married Sally. Sally's mom is Sarah. Sarah is Bob's ______. A. brother B. father in law C. step son D. mother in law E. grandfather F. dog G. lover Obviously the correct answer is either D or G, but how would the bot figure that out? Instead of captcha, what about something like the following, which is quick and easy, and hard for a bot to get past…

To Continue Answer the following:

Bob married Sally. Sally’s mom is Sarah. Sarah is Bob’s ______.

A. brother
B. father in law
C. step son
D. mother in law
E. grandfather
F. dog
G. lover

Obviously the correct answer is either D or G, but how would the bot figure that out?

]]> By: Google censoring conservative political emails? « Reformed Musings http://alastairc.ac/2006/12/why-does-google-use-captcha/comment-page-1/#comment-90279 Google censoring conservative political emails? « Reformed Musings Sun, 14 Sep 2008 22:31:45 +0000 http://alastairc.ac/2006/12/why-does-google-use-captcha/#comment-90279 [...] to thwart spammers, they are easily and routinely cracked by universities and hackers. There are better alternatives. Nonetheless, I went to the web interface for Google mail to get things rolling again. I noticed [...] [...] to thwart spammers, they are easily and routinely cracked by universities and hackers. There are better alternatives. Nonetheless, I went to the web interface for Google mail to get things rolling again. I noticed [...]

]]> By: AlastairC http://alastairc.ac/2006/12/why-does-google-use-captcha/comment-page-1/#comment-80758 AlastairC Tue, 26 Aug 2008 07:33:07 +0000 http://alastairc.ac/2006/12/why-does-google-use-captcha/#comment-80758 Hi Aby, You've pretty much missed the point of the article really. There isn't such a thing as a good CAPTCHA,and looking at yours hasn't changed my mind. Apart from just having one modality, the images aren't that hard to read, meaning they will be easliy crackable. If I were to use a CAPTCHA service, it would be <a href="http://recaptcha.net/" rel="nofollow">recaptcha.net</a>, as it offers an audio equivalent and works for a good cause. Hi Aby,

You’ve pretty much missed the point of the article really. There isn’t such a thing as a good CAPTCHA,and looking at yours hasn’t changed my mind.

Apart from just having one modality, the images aren’t that hard to read, meaning they will be easliy crackable.

If I were to use a CAPTCHA service, it would be recaptcha.net, as it offers an audio equivalent and works for a good cause.

]]> By: aby http://alastairc.ac/2006/12/why-does-google-use-captcha/comment-page-1/#comment-80609 aby Tue, 26 Aug 2008 02:42:40 +0000 http://alastairc.ac/2006/12/why-does-google-use-captcha/#comment-80609 Captcha is a tool to distinguish between human and automated programs. Unfortunately most of the captcha are a burden to users. An ideal captcha should be easily readable to human and rarely understandable to hacker applications. I have created such a captcha and published in my blog. I have a plan to establish it as a service. I.e. you can include it as a plug-in to your web site. Please give your valuable comments regarding this. http://www.codegeeks.net/captcha-using-aspnet Captcha is a tool to distinguish between human and automated programs. Unfortunately most of the captcha are a burden to users. An ideal captcha should be easily readable to human and rarely understandable to hacker applications. I have created such a captcha and published in my blog. I have a plan to establish it as a service. I.e. you can include it as a plug-in to your web site. Please give your valuable comments regarding this.
http://www.codegeeks.net/captcha-using-aspnet

]]> By: AlastairC http://alastairc.ac/2006/12/why-does-google-use-captcha/comment-page-1/#comment-62858 AlastairC Mon, 21 Jul 2008 11:02:50 +0000 http://alastairc.ac/2006/12/why-does-google-use-captcha/#comment-62858 Stats from testing a form with and without CAPTCHA showed a <a href="http://marcelo.sampa.com/marcelo-calbucci/brave-tech-world/A-10-improvement-on-conversion-w.htm" rel="nofollow">10% increase in (human) conversion</a>. They used certain rules that only showed a CAPTCHA in certain cases (<1% of the time), but more most people they didn't have to use it. Stats from testing a form with and without CAPTCHA showed a 10% increase in (human) conversion.

They used certain rules that only showed a CAPTCHA in certain cases (<1% of the time), but more most people they didn’t have to use it.

]]> By: AlastairC http://alastairc.ac/2006/12/why-does-google-use-captcha/comment-page-1/#comment-47409 AlastairC Wed, 07 May 2008 08:37:06 +0000 http://alastairc.ac/2006/12/why-does-google-use-captcha/#comment-47409 <blockquote><p>LIE!!!! It only breaks the Gimpy captcha.</p></blockquote> That was just one example, more recently people have been <a href="http://tech.blorge.com/Structure:%20/2007/07/08/spammers-overcome-hotmail-and-yahoo-captcha-systems/" rel="nofollow">breaking Yahoo and Microsoft's CAPTCHA</a>. As for false positives, all of the systems will produce them to some extent, but my hit rate getting through CAPTCHA is about 1 in 2... less than the others.

LIE!!!! It only breaks the Gimpy captcha.

That was just one example, more recently people have been breaking Yahoo and Microsoft’s CAPTCHA.

As for false positives, all of the systems will produce them to some extent, but my hit rate getting through CAPTCHA is about 1 in 2… less than the others.

]]> By: Gerry http://alastairc.ac/2006/12/why-does-google-use-captcha/comment-page-1/#comment-47377 Gerry Wed, 07 May 2008 02:58:47 +0000 http://alastairc.ac/2006/12/why-does-google-use-captcha/#comment-47377 > It is not effective. People have created systems to break it in 92% of cases. LIE!!!! It only breaks the Gimpy captcha. At least read the damn article that you link to. > There are better methods. WRONG!!!! Your "better methods" lead to false positives, which is the only thing that's worse than spam. > It is not effective. People have created systems to break it in 92% of cases.

LIE!!!! It only breaks the Gimpy captcha. At least read the damn article that you link to.

> There are better methods.

WRONG!!!! Your “better methods” lead to false positives, which is the only thing that’s worse than spam.

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