Abstract
Security researchers have, for long, devised mechanismsto prevent adversaries from conducting automated networkattacks, such as denial-of-service, which lead to significantwastage of resources. On the other hand, several attempts havebeen made to automatically recognize generic images, make themsemantically searchable by content, annotate them, and associatethem with linguistic indexes. In the course of these attempts, thelimitations of state-of-the-art algorithms in mimicking humanvision have become exposed. In this paper, we ....etc

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C.A.P.T.C.H.A
Completely Automated Public Turing Test to Tell Computers and Humans Apart

Abstract
A CAPTCHA (an acronym for completely automated public Turing test to tell computers and humans apart, trademarked by Carnegie Mellon University) or a MAPTCHA (Mathematical) is a type of challenge-response test used in computing to determine whether or not the user is human. The term was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper of Carnegie Mellon University, and John Langford of IBM. A common type of CAPTCHA requires t ....etc

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i need algorithms used to generate captchas for my presentation (ppt) and (doc)
....etc

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Abstract.
We introduce captcha, an automated test that humans can pass, but current computer programs canâ„¢t pass: any program that has high success over a captcha can be used to solve an unsolved Arti?- cial Intelligence (AI) problem. We provide several novel constructions of captchas. Since captchas have many applications in practical secu- rity, our approach introduces a new class of hard problems that can be exploited for security purposes. Much like research in cryptography has had a positive impact on algorithms for factoring and ....etc

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Abstract.
We introduce captcha, an automated test that humans can pass, but current computer programs canâ„¢t pass: any program that has high success over a captcha can be used to solve an unsolved Arti?- cial Intelligence (AI) problem. We provide several novel constructions of captchas. Since captchas have many applications in practical secu- rity, our approach introduces a new class of hard problems that can be exploited for security purposes. Much like research in cryptography has had a positive impact on algorithms for factoring and ....etc

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sir,
Iam BE computer science & engg. student.May i get seminar report and ppt on the topic captcha. ....etc

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Evaluating Existing Audio CAPTCHAs and an Interface Optimized for Non-Visual Use




INTRODUCTION AND MOTIVATION

The goal of a CAPTCHA1 is to dierentiate humans
from automated agents by requesting the solution to a
problem that is easy for humans but dicult for com-
puters. CAPTCHAs are used to guard access to web re-
sources and, therefore, prevent automated agents


Making CAPTCHAs Accessible

Audio CAPTCHAs were introduced soon after their vi-
sual alterna ....etc

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Evaluating Existing Audio CAPTCHAs and an Interface Optimized for Non-Visual Use




INTRODUCTION AND MOTIVATION

The goal of a CAPTCHA1 is to dierentiate humans
from automated agents by requesting the solution to a
problem that is easy for humans but dicult for com-
puters. CAPTCHAs are used to guard access to web re-
sources and, therefore, prevent automated agents


Making CAPTCHAs Accessible

Audio CAPTCHAs were introduced soon after their vi-
sual alterna ....etc

[:=Read Full Message Here=:]

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, ....etc

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Presented by:
SANDEEP MEHTA


IMPROVING AUDITORY CAPTCHA SECURITY
Introduction
CAPTCHA
A common type of CAPTCHA requires the user to type the letters of a distorted image sometimes with the addition of an obscured sequence of letters or digits appears on screen.
This string which the user has to type to submit a form .This is a simple problem for humans, but a very hard problem for computers which have to use character recognition, because the displayed string is alienated in a way, which ma ....etc

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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, ....etc

[:=Read Full Message Here=:]

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, ....etc

[:=Read Full Message Here=:]

Abstract
Security researchers have, for long, devised mechanismsto prevent adversaries from conducting automated networkattacks, such as denial-of-service, which lead to significantwastage of resources. On the other hand, several attempts havebeen made to automatically recognize generic images, make themsemantically searchable by content, annotate them, and associatethem with linguistic indexes. In the course of these attempts, thelimitations of state-of-the-art algorithms in mimicking humanvision have become exposed. In this paper, we ....etc

[:=Read Full Message Here=:]

Breaking Audio CAPTCHAs




Introduction

CAPTCHAs are automated tests designed to tell computers and humans apart by
presenting users with a problem that humans can solve but current computer programs
cannot. Because CAPTCHAs can distinguish between humans and computers with high
probability, they are used for many different security applications: they prevent bots from
voting continuously in online polls, automatically registering for ....etc

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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, ....etc

[:=Read Full Message Here=:]

Seminar Report onAudio CAPTCHA: Existing solutions assessment and It’s Advancements
What are CAPTCHAs?
Completely Automated Public Test to Tell Computers and Humans Apart.
Web-based protection mechanisms
Only humans allowed to perform certain tasks
Opening E-mail accounts
Voting on-line, etc.
Prevent automated attacks by bots
To avoid eating up resources
To avoid biasing results, etc.
Most current systems - text-based.
Why there came a need for Captchas???
Preventing Comment Spam in Blogs. 
Protec ....etc

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