Many of us many times visited many web pages filled many web forms in the Websites filled many CAPTCHA challenges but do you know why CAPTCHA ?
Okay , lets know it
CAPTCHA is used to make sure that the entity filling out a form, commenting on a blog, or registering for a website is an actual person instead of a bot trying to spam the site.
This comes from the most popular CAPTCHA company out there, ReCAPTCHA. It is reliable, but some of the distorted word images are rather hard to solve. To get past that it allows you the option to “reCAPTCHA,” in order to receive a new one. There is also an audio option if you are unable to visually make out the word.
2. Picture Identification CAPTCHA
This CAPTCHA by Picatcha provides the user with an elementary choice of choosing the correct image that they are asked to identify. They never get harder than basic images so you won’t have to worry too much about your users not being able to depict the difference between them and the incorrect images.
3. Math Solving CAPTCHA
If your users can’t solve these basic math problems then maybe you don’t want them commenting on your threads anyways. These provide you with easy to read numbers that must be added in order to get past the CAPTCHA.
4. 3D CAPTCHA
This one may be one of the more difficult ones to solve, but it is sure to keep out robotic predators. There are several types of three dimensional CAPTCHAs including both images and words. They call it the “super-CAPTCA.”
5. Ad-Injected CAPTCHA
If your users are spending a few seconds everyday on CAPTCHAs why not earn some extra cash for your website? This may seem iffy for the brand as they are associating themselves with a rather annoying process, but it does make sense in terms of brand recognition. This particular example is of the main company providing this known as Solve Media. Publishers get paid on a 60/40 split with Solve Media (Solve Media taking 60%) on a per solve/impression basis.
· Preventing Comment Spam in Blogs. Most bloggers are familiar with programs that submit bogus comments, usually for the purpose of raising search engine ranks of some website (e.g., "buy penny stocks here"). This is called comment spam. By using a CAPTCHA, only humans can enter comments on a blog. There is no need to make users sign up before they enter a comment, and no legitimate comments are ever lost!
· Protecting Website Registration. Several companies (Yahoo!, Microsoft, etc.) offer free email services. Up until a few years ago, most of these services suffered from a specific type of attack: "bots" that would sign up for thousands of email accounts every minute. The solution to this problem was to use CAPTCHAs to ensure that only humans obtain free accounts. In general, free services should be protected with a CAPTCHA in order to prevent abuse by automated scripts.
· Protecting Email Addresses From Scrapers. Spammers crawl the Web in search of email addresses posted in clear text. CAPTCHAs provide an effective mechanism to hide your email address from Web scrapers. The idea is to require users to solve a CAPTCHA before showing your email address.
· Online Polls. In November 1999, http://www.slashdot.org released an online poll asking which was the best graduate school in computer science (a dangerous question to ask over the web!). As is the case with most online polls, IP addresses of voters were recorded in order to prevent single users from voting more than once. However, students at Carnegie Mellon found a way to stuff the ballots using programs that voted for CMU thousands of times. CMU's score started growing rapidly. The next day, students at MIT wrote their own program and the poll became a contest between voting "bots." MIT finished with 21,156 votes, Carnegie Mellon with 21,032 and every other school with less than 1,000. Can the result of any online poll be trusted? Not unless the poll ensures that only humans can vote.
· Preventing Dictionary Attacks. CAPTCHAs can also be used to prevent dictionary attacks in password systems. The idea is simple: prevent a computer from being able to iterate through the entire space of passwords by requiring it to solve a CAPTCHA after a certain number of unsuccessful logins. This is better than the classic approach of locking an account after a sequence of unsuccessful logins, since doing so allows an attacker to lock accounts at will.
· Search Engine Bots. It is sometimes desirable to keep webpages unindexed to prevent others from finding them easily. There is an html tag to prevent search engine bots from reading web pages. The tag, however, doesn't guarantee that bots won't read a web page; it only serves to say "no bots, please." Search engine bots, since they usually belong to large companies, respect web pages that don't want to allow them in. However, in order to truly guarantee that bots won't enter a web site, CAPTCHAs are needed.
· Worms and Spam. CAPTCHAs also offer a plausible solution against email worms and spam: "I will only accept an email if I know there is a human behind the other computer." A few companies are already marketing this idea.
references
-http://www.findexamples.com
Many of us many times visited many web pages filled many web forms in the Websites filled many CAPTCHA challenges but do you know why CAPTCHA ?
Okay , lets know it
CAPTCHA is used to make sure that the entity filling out a form, commenting on a blog, or registering for a website is an actual person instead of a bot trying to spam the site.
![clip_image004[4]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjA9oR4z-kwrH6GwCl2LBclSKepgjTRWkDUgPQ_Ghjs6dbTKocCXP5U1JCJiFub5CndSNAefY97YMwYLiamdF85YMYb_iqhLnieg4mH1_2DsdWVVtNLJ_O896lY3fqfgkb7pKFNy7neTWPj/?imgmax=800 "clip_image004[4]")
This comes from the most popular CAPTCHA company out there, ReCAPTCHA. It is reliable, but some of the distorted word images are rather hard to solve. To get past that it allows you the option to “reCAPTCHA,” in order to receive a new one. There is also an audio option if you are unable to visually make out the word.
2. Picture Identification CAPTCHA
![clip_image006[4]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXz7TBDWG2fQVY14CTDNBDMZHxASLRD-uXp8lrtJwsvyv4-z3WtmKoBRLsjxsdOxGOtp7_9R8ELTUy0nrqXQlJtawoltvgWN8Qc1L2PosyQ3jWiwTb6MMzxSYZZqswmtp3c53ZcKLB9a79/?imgmax=800 "clip_image006[4]")
This CAPTCHA by Picatcha provides the user with an elementary choice of choosing the correct image that they are asked to identify. They never get harder than basic images so you won’t have to worry too much about your users not being able to depict the difference between them and the incorrect images.
3. Math Solving CAPTCHA
![clip_image008[4]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnp2ksj0WoR5DdcUKHwyAhDqt7PGiKRhaX8dRSuhT6KuqhrCtfwwYJB0FWgqdwTOHsgVEuwOJOM68YTRKxPfvbbVpG76Fgz0vzrTk2u2_TlfRluSIKmvOGiifXB117XSBAxV7ft2kY6xmZ/?imgmax=800 "clip_image008[4]")
If your users can’t solve these basic math problems then maybe you don’t want them commenting on your threads anyways. These provide you with easy to read numbers that must be added in order to get past the CAPTCHA.
4. 3D CAPTCHA
![clip_image010[4]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSjW7a0yG2XwNuajtgdTtzrme1fWp5bR8nGecjYPe14WDr3W_yzF0EqXoOJmaI-NeAOVRXGEZBhmR5iXSgnXGTQ2iqsUt-wbp3DrULTGHTt4gUKeHDp3j20loAtRhV4AMH6FJnR5VlZOSq/?imgmax=800 "clip_image010[4]")
This one may be one of the more difficult ones to solve, but it is sure to keep out robotic predators. There are several types of three dimensional CAPTCHAs including both images and words. They call it the “super-CAPTCA.”
5. Ad-Injected CAPTCHA
![clip_image011[4]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5HlHMyIiNQ3ewykxx9QGmKHy73PO-y9OGTYjaDWjCTPzlQBTBzTdM8lVokVXLRA_-LE3SicLI067tXoubYfIMdKoUi5WsHB7zHZDqe6So_FqX7-20bcjGBc3qjhHvNJM5SRTm2nV3Sm8f/?imgmax=800 "clip_image011[4]")
If your users are spending a few seconds everyday on CAPTCHAs why not earn some extra cash for your website? This may seem iffy for the brand as they are associating themselves with a rather annoying process, but it does make sense in terms of brand recognition. This particular example is of the main company providing this known as Solve Media. Publishers get paid on a 60/40 split with Solve Media (Solve Media taking 60%) on a per solve/impression basis.
· Preventing Comment Spam in Blogs. Most bloggers are familiar with programs that submit bogus comments, usually for the purpose of raising search engine ranks of some website (e.g., "buy penny stocks here"). This is called comment spam. By using a CAPTCHA, only humans can enter comments on a blog. There is no need to make users sign up before they enter a comment, and no legitimate comments are ever lost!
· Protecting Website Registration. Several companies (Yahoo!, Microsoft, etc.) offer free email services. Up until a few years ago, most of these services suffered from a specific type of attack: "bots" that would sign up for thousands of email accounts every minute. The solution to this problem was to use CAPTCHAs to ensure that only humans obtain free accounts. In general, free services should be protected with a CAPTCHA in order to prevent abuse by automated scripts.
· Protecting Email Addresses From Scrapers. Spammers crawl the Web in search of email addresses posted in clear text. CAPTCHAs provide an effective mechanism to hide your email address from Web scrapers. The idea is to require users to solve a CAPTCHA before showing your email address.
· Online Polls. In November 1999, http://www.slashdot.org released an online poll asking which was the best graduate school in computer science (a dangerous question to ask over the web!). As is the case with most online polls, IP addresses of voters were recorded in order to prevent single users from voting more than once. However, students at Carnegie Mellon found a way to stuff the ballots using programs that voted for CMU thousands of times. CMU's score started growing rapidly. The next day, students at MIT wrote their own program and the poll became a contest between voting "bots." MIT finished with 21,156 votes, Carnegie Mellon with 21,032 and every other school with less than 1,000. Can the result of any online poll be trusted? Not unless the poll ensures that only humans can vote.
· Preventing Dictionary Attacks. CAPTCHAs can also be used to prevent dictionary attacks in password systems. The idea is simple: prevent a computer from being able to iterate through the entire space of passwords by requiring it to solve a CAPTCHA after a certain number of unsuccessful logins. This is better than the classic approach of locking an account after a sequence of unsuccessful logins, since doing so allows an attacker to lock accounts at will.
· Search Engine Bots. It is sometimes desirable to keep webpages unindexed to prevent others from finding them easily. There is an html tag to prevent search engine bots from reading web pages. The tag, however, doesn't guarantee that bots won't read a web page; it only serves to say "no bots, please." Search engine bots, since they usually belong to large companies, respect web pages that don't want to allow them in. However, in order to truly guarantee that bots won't enter a web site, CAPTCHAs are needed.
· Worms and Spam. CAPTCHAs also offer a plausible solution against email worms and spam: "I will only accept an email if I know there is a human behind the other computer." A few companies are already marketing this idea.
references
-http://www.findexamples.com
-http://www.CAPTCHA.net/
-http://c2.com/cgi/wiki?CAPTCHATest
-http://www.howstuffworks.com
-http://en.wikipedia.org/wiki/CAPTCHA
-http://www.CAPTCHA.net/
-http://c2.com/cgi/wiki?CAPTCHATest
-http://www.howstuffworks.com
-http://en.wikipedia.org/wiki/CAPTCHA
Okay , lets know it
What is CAPTCHA?
CAPTCHA, an acronym that stands for Completely Automated Public Turing Test to Tell Computers and Humans Apart. They're also known as a type of Human Interaction Proof (HIP).CAPTCHA is used to make sure that the entity filling out a form, commenting on a blog, or registering for a website is an actual person instead of a bot trying to spam the site.
Types of CAPTCHAs
1. The Standard Distorted Word CAPTCHA with an Audio Option
This comes from the most popular CAPTCHA company out there, ReCAPTCHA. It is reliable, but some of the distorted word images are rather hard to solve. To get past that it allows you the option to “reCAPTCHA,” in order to receive a new one. There is also an audio option if you are unable to visually make out the word.
2. Picture Identification CAPTCHA
This CAPTCHA by Picatcha provides the user with an elementary choice of choosing the correct image that they are asked to identify. They never get harder than basic images so you won’t have to worry too much about your users not being able to depict the difference between them and the incorrect images.
3. Math Solving CAPTCHA
If your users can’t solve these basic math problems then maybe you don’t want them commenting on your threads anyways. These provide you with easy to read numbers that must be added in order to get past the CAPTCHA.
4. 3D CAPTCHA
This one may be one of the more difficult ones to solve, but it is sure to keep out robotic predators. There are several types of three dimensional CAPTCHAs including both images and words. They call it the “super-CAPTCA.”
5. Ad-Injected CAPTCHA
If your users are spending a few seconds everyday on CAPTCHAs why not earn some extra cash for your website? This may seem iffy for the brand as they are associating themselves with a rather annoying process, but it does make sense in terms of brand recognition. This particular example is of the main company providing this known as Solve Media. Publishers get paid on a 60/40 split with Solve Media (Solve Media taking 60%) on a per solve/impression basis.
Applications of CAPTCHAs
CAPTCHAs have several applications for practical security, including (but not limited to):· Preventing Comment Spam in Blogs. Most bloggers are familiar with programs that submit bogus comments, usually for the purpose of raising search engine ranks of some website (e.g., "buy penny stocks here"). This is called comment spam. By using a CAPTCHA, only humans can enter comments on a blog. There is no need to make users sign up before they enter a comment, and no legitimate comments are ever lost!
· Protecting Website Registration. Several companies (Yahoo!, Microsoft, etc.) offer free email services. Up until a few years ago, most of these services suffered from a specific type of attack: "bots" that would sign up for thousands of email accounts every minute. The solution to this problem was to use CAPTCHAs to ensure that only humans obtain free accounts. In general, free services should be protected with a CAPTCHA in order to prevent abuse by automated scripts.
· Protecting Email Addresses From Scrapers. Spammers crawl the Web in search of email addresses posted in clear text. CAPTCHAs provide an effective mechanism to hide your email address from Web scrapers. The idea is to require users to solve a CAPTCHA before showing your email address.
· Online Polls. In November 1999, http://www.slashdot.org released an online poll asking which was the best graduate school in computer science (a dangerous question to ask over the web!). As is the case with most online polls, IP addresses of voters were recorded in order to prevent single users from voting more than once. However, students at Carnegie Mellon found a way to stuff the ballots using programs that voted for CMU thousands of times. CMU's score started growing rapidly. The next day, students at MIT wrote their own program and the poll became a contest between voting "bots." MIT finished with 21,156 votes, Carnegie Mellon with 21,032 and every other school with less than 1,000. Can the result of any online poll be trusted? Not unless the poll ensures that only humans can vote.
· Preventing Dictionary Attacks. CAPTCHAs can also be used to prevent dictionary attacks in password systems. The idea is simple: prevent a computer from being able to iterate through the entire space of passwords by requiring it to solve a CAPTCHA after a certain number of unsuccessful logins. This is better than the classic approach of locking an account after a sequence of unsuccessful logins, since doing so allows an attacker to lock accounts at will.
· Search Engine Bots. It is sometimes desirable to keep webpages unindexed to prevent others from finding them easily. There is an html tag to prevent search engine bots from reading web pages. The tag, however, doesn't guarantee that bots won't read a web page; it only serves to say "no bots, please." Search engine bots, since they usually belong to large companies, respect web pages that don't want to allow them in. However, in order to truly guarantee that bots won't enter a web site, CAPTCHAs are needed.
· Worms and Spam. CAPTCHAs also offer a plausible solution against email worms and spam: "I will only accept an email if I know there is a human behind the other computer." A few companies are already marketing this idea.
references
-http://www.findexamples.com
Many of us many times visited many web pages filled many web forms in the Websites filled many CAPTCHA challenges but do you know why CAPTCHA ?
Okay , lets know it
What is CAPTCHA?
CAPTCHA, an acronym that stands for Completely Automated Public Turing Test to Tell Computers and Humans Apart. They're also known as a type of Human Interaction Proof (HIP).CAPTCHA is used to make sure that the entity filling out a form, commenting on a blog, or registering for a website is an actual person instead of a bot trying to spam the site.
![clip_image002[4]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4QyVoi7GMhwowtauGUxcHcGOTttkMa7UPXB1oFbiHNFHZWu2eq7-ijtHIZB9G94EkpIAhVPrDwjbFmH_drDER41pdHIMkpayXao17AbQMAX_g7GL6pte3InxHganstdeUsjzsnyuJajbQ/s1600-h/clip_image002%25255B4%25255D%25255B2%25255D.jpg "clip_image002[4]")
Types of CAPTCHAs
1. The Standard Distorted Word CAPTCHA with an Audio Option This comes from the most popular CAPTCHA company out there, ReCAPTCHA. It is reliable, but some of the distorted word images are rather hard to solve. To get past that it allows you the option to “reCAPTCHA,” in order to receive a new one. There is also an audio option if you are unable to visually make out the word.
2. Picture Identification CAPTCHA
This CAPTCHA by Picatcha provides the user with an elementary choice of choosing the correct image that they are asked to identify. They never get harder than basic images so you won’t have to worry too much about your users not being able to depict the difference between them and the incorrect images.
3. Math Solving CAPTCHA
If your users can’t solve these basic math problems then maybe you don’t want them commenting on your threads anyways. These provide you with easy to read numbers that must be added in order to get past the CAPTCHA.
4. 3D CAPTCHA
This one may be one of the more difficult ones to solve, but it is sure to keep out robotic predators. There are several types of three dimensional CAPTCHAs including both images and words. They call it the “super-CAPTCA.”
5. Ad-Injected CAPTCHA
If your users are spending a few seconds everyday on CAPTCHAs why not earn some extra cash for your website? This may seem iffy for the brand as they are associating themselves with a rather annoying process, but it does make sense in terms of brand recognition. This particular example is of the main company providing this known as Solve Media. Publishers get paid on a 60/40 split with Solve Media (Solve Media taking 60%) on a per solve/impression basis.
Applications of CAPTCHAs
CAPTCHAs have several applications for practical security, including (but not limited to):· Preventing Comment Spam in Blogs. Most bloggers are familiar with programs that submit bogus comments, usually for the purpose of raising search engine ranks of some website (e.g., "buy penny stocks here"). This is called comment spam. By using a CAPTCHA, only humans can enter comments on a blog. There is no need to make users sign up before they enter a comment, and no legitimate comments are ever lost!
· Protecting Website Registration. Several companies (Yahoo!, Microsoft, etc.) offer free email services. Up until a few years ago, most of these services suffered from a specific type of attack: "bots" that would sign up for thousands of email accounts every minute. The solution to this problem was to use CAPTCHAs to ensure that only humans obtain free accounts. In general, free services should be protected with a CAPTCHA in order to prevent abuse by automated scripts.
· Protecting Email Addresses From Scrapers. Spammers crawl the Web in search of email addresses posted in clear text. CAPTCHAs provide an effective mechanism to hide your email address from Web scrapers. The idea is to require users to solve a CAPTCHA before showing your email address.
· Online Polls. In November 1999, http://www.slashdot.org released an online poll asking which was the best graduate school in computer science (a dangerous question to ask over the web!). As is the case with most online polls, IP addresses of voters were recorded in order to prevent single users from voting more than once. However, students at Carnegie Mellon found a way to stuff the ballots using programs that voted for CMU thousands of times. CMU's score started growing rapidly. The next day, students at MIT wrote their own program and the poll became a contest between voting "bots." MIT finished with 21,156 votes, Carnegie Mellon with 21,032 and every other school with less than 1,000. Can the result of any online poll be trusted? Not unless the poll ensures that only humans can vote.
· Preventing Dictionary Attacks. CAPTCHAs can also be used to prevent dictionary attacks in password systems. The idea is simple: prevent a computer from being able to iterate through the entire space of passwords by requiring it to solve a CAPTCHA after a certain number of unsuccessful logins. This is better than the classic approach of locking an account after a sequence of unsuccessful logins, since doing so allows an attacker to lock accounts at will.
· Search Engine Bots. It is sometimes desirable to keep webpages unindexed to prevent others from finding them easily. There is an html tag to prevent search engine bots from reading web pages. The tag, however, doesn't guarantee that bots won't read a web page; it only serves to say "no bots, please." Search engine bots, since they usually belong to large companies, respect web pages that don't want to allow them in. However, in order to truly guarantee that bots won't enter a web site, CAPTCHAs are needed.
· Worms and Spam. CAPTCHAs also offer a plausible solution against email worms and spam: "I will only accept an email if I know there is a human behind the other computer." A few companies are already marketing this idea.
references
-http://www.findexamples.com
-http://www.CAPTCHA.net/
-http://c2.com/cgi/wiki?CAPTCHATest
-http://www.howstuffworks.com
-http://en.wikipedia.org/wiki/CAPTCHA
-http://www.CAPTCHA.net/
-http://c2.com/cgi/wiki?CAPTCHATest
-http://www.howstuffworks.com
-http://en.wikipedia.org/wiki/CAPTCHA
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