captchas for web security

this is general introduction slide about captcha it includes problem statement, objectives, methodologies, results, discussions and conclusion it was prepared for classroom presentation by binaya of st xaviers college

1. PRESENTED BY: Binaya Paudel
CSIT
021BSCIT007
“A STUDY OF CAPTCHAS
FOR SECURING WEB
SERVICES”
A Journal Club Presentation
ON

2. Introduction1
Problem Statement2
Objective3
Methodology4
Result and Analysis 5
Contents
Discussion6
Conclusion7
References
8
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3. INTRODUCTION
1. CAPTCHA is a tool to tell humans and
bots apart online.
2. It presents challenges easy for
humans but hard for bots.
3. Well-designed CAPTCHAs balance
ease of use with security.
4. This paper explores CAPTCHA types,
generation, and improvements for the
future.
CAPTCHA stands for "Completely Automated
Public Turing test to tell Computers and Humans
Apart."
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4. binaya paudel

5. •The internet's massive growth
necessitates replacing human
interactions with automated
processes, but malicious web-bots
pretending to be humans threaten
online services that assume human
interaction.
Problem statement
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6. How bots affect the
services?
•Spam
•Security Risks
•Overloading Servers
•Manipulation of Services
•Financial Loss
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7. OBJECTIVES
•EVALUATE: To evaluate the limitations and challenges of current text-based CAPTCHA
systems, such as decreased usability for ordinary users, localization issues, and vulnerability to
advances in OCR techniques.
•ASSESS: To assess the drawbacks of proposed image-based CAPTCHA alternatives, including
larger web page area requirements, increased server processing, and susceptibility to attacks.
•IDENTIFY: To identify the need for new CAPTCHA techniques that prioritize user-friendliness,
require minimal server processing, and offer enhanced security against bots.
•EMPHASIZE: To emphasize the importance of rigorous validation of the effectiveness and
robustness of new CAPTCHA methods in the face of evolving bot technologies and increasing
sophistication of attacks.
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8. Literature
Review
Introduction to HIPs
and CAPTCHA
methods, discussing
their purpose,
functionality,
advantages, and
disadvantages based
on existing literature.
Working of
CAPTCHA
Description of
CAPTCHA functioning:
image generation,
state storage, user
presentation,
response, and server
verification.
Issues in
CAPTCHA Design
Discussion of security
and usability issues in
CAPTCHA design,
including vulnerability
to attacks, schemes
breaking, security
methods, and usability
improvements.
Methodology
Types of CAPTCHA
Methods
Categorization of
CAPTCHA methods:
text-based, image-
based, audio-based,
and others, with
detailed explanations
and examples
provided for each
category.
LM = Language Model
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9. Working of CAPTCHA
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10. •Working of CAPTCHA: Explains the process of how
CAPTCHAs function, including CAPTCHA image
generation, storage of state information, verification of
user responses, and access control to protected
resources.
•Issues in CAPTCHA Design: Addresses security issues
related to CAPTCHAs, including vulnerability to attacks
such as dictionary attacks and man-in-the-middle
attacks. It also discusses methods to secure CAPTCHAs
against such attacks.
•Improving Usability: Highlights usability issues
associated with CAPTCHAs, such as accuracy, response
time, and perceived difficulty. It suggests methods to
improve usability, including controlled distortion,
appropriate presentation, and consideration of
accessibility for disabled users.
RESULTS
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11. DISCUSSIONS
•Why is captcha used and is it the best way to secure web
from bots?
CAPTCHA is used to distinguish humans from bots online. While it's
effective to some extent, it's not always the best solution due to usability
issues and susceptibility to advanced bot attacks.
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12. CONCLUSIONS
•The research explores CAPTCHA, a tool used to tell
humans and bots apart online. While CAPTCHA helps
boost web security, it's not perfect. Bots are getting
smarter, and CAPTCHA can be annoying for users. It's still
widely used, but we need to think about other ways to
keep bots at bay while keeping things easy for humans
online.
•
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13. [1] H. Baird and K. Popat, “Human
Interactive Proofs
and Document Image Analysis”, In
Proceedings of
the 5th IAPR International
Workshop on
Document Analysis Systems
(DAS'02), Princeton,
NJ, USA, 2002, Vol. 2423 of Lecture
Notes in
Computer Science (LNCS), pp.
531-537, Springer.
REFERENCES
M. Blum, L. A. von Ahn, and J.
Langford, “The
CAPTCHA Project, Completely
Automatic Public
Turing Test to Tell Computers
and Humans Apart,”
Nov. 2000,
http://www.captcha.net, Dept.
of
Computer Science,
Carnegie-Mellon Univ.
S. Shirali-Shahreza, M.
Shirali-Shahreza and M. T.
Manzuri-Shalmani,”Easy
and Secure Login by
CAPTCHA,” International
Review on Computers
and Software (IRECOS)”,
Vol. 2, No. 4, July
2007, pp. 393-400.
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14. THANK YOU !
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