13-06-2009, 07:03 PM
Captchas are tests that distinguish human from software botsin an online environment, used to stop bots abusing services intended for humans. Paypal and Yahoo have captchas in their new user registration process, but there are programs toovercome them. Investigate proposals for new kinds of captchas. Captchas are used to prevent bots from using various types of computing services. Applications include preventing bots from taking part in online polls, registering for free email accounts (which may then be used to send spam), and, more recently, preventing bot-generated spam by requiring that the (unrecognized) sender pass a captcha test before the email message is delivered.
Captchas are by definition fully automated, requiring little human maintenance or intervention in administering the test. This has obvious benefits in cost and reliability.
The algorithm used to create the captcha is often made public, though it may be covered by a patent. This is done to demonstrate that breaking it requires the solution of a hard problem in the field of artificial intelligence (AI) rather than just the discovery of the (secret) algorithm, which could be obtained through reverse engineering or other means.
They are programs or tests that help to differentiate human from software bots in the internet environment.. Widely used by Paypal and Yahoo in their new user registration process, captchas prevents the software bots from misusing the various services provided to the human.
They are programs or tests that help to differentiate human from software bots in the internet environment.. Widely used by Paypal and Yahoo in their new user registration process, captchas prevents the software bots from misusing the various services provided to the human.
