3d captcha 1

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3D CAPTCHAA next generation of the Captcha

-Niriksha shetty

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Contents

1.Origin

2. Introduction

1.1. Characteristics

1.2. Captcha methods

3. Related works

4. Proposed method

5. Results

6. Conclusion

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ORIGIN

F i r s t dev e l oped by A l t a V i s t a i n 1997 . T he

te rm co ined in 2000 by Lu i s von Ahn ,

M a n ue l B l um a n d N i c ho l a s J . H opper o f

Carneg i e Me l lon Un i ve r s i t y and JohnLa n g fo r d o f IB M .

P r i m i t i v e CA PT CH As seem t o ha v e been

dev e l oped i n 1997 by A n dr e i B r ode r , M a r t i n

Abad i , K r i shna Bh ar a t , and Mark L i l l i b r idget o p r ev en t bo t s f r om a dd i n g U R Ls t o t he i r

sea r ch eng ine .

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Introduction

CAPTCHA - Completely Automated Public Turing test to

tell Computers and Humans Apart.

Turing Test is a test for determining whether or not

machine intelligence can converse like a human.

The CAPTCHA is used to keep bots and other automated

programs from signing up for offers, collecting or signing

up for email address, violating privacy, trying to crack

passwords, or sending out spam to unsuspecting email

recipients.

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Introduction

A CAPTCHA is a program that protects websites

against bots by generating and grading tests thathumans can pass but current computer programs

cannot.

It is a type of challenge-response test used in

computing to ensure that the response is notgenerated by a computer.

CAPTCHA requires the user type letters or digits

from a distorted image that appears on the screen.

Any user entering a correct solution is presumed tobe human else user is bot and denied access.

CAPTCHAs rely on difficult problems in artificial

intelligence .

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Characteristics:

A CAPTCHA is a means of automatically generating

new challenges which:

Current software is unable to solve accurately.

Most humans can solve.

Does not rely on the type of CAPTCHA being new

to the attacker.

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Applications

1.)Rediffmail

Overlapping characters.

Noisy background.

Difficult to read.

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Applications

2.) Google

Pure white background.

Single color character.

Different fonts.

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Applications

3.) Hotmail

Sequence of characters.

Easy by human.

Difficult for OCR.

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Applications

4.) Friendster

Many fonts in sequence.

Colorful and easy.

No overlapping.

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Applications

5.) eBay

Only digits.

No background.

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Proposedmethod

To develop a sequence of 3D characters which is easily

recognizable by human but difficult by an OCR.

The basis for a strong OCR-based CAPTCHA is ensuring thatsegmentation is hard.

The CAPTCHA text consists of a total of 6 alphanumeric

characters which are letters and numbers.

Each has its own axis and rotation angle, ranging from -45 to

45 generated using standard randomization function.

CAPTCHA images are generated by using DirectX.

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ProposedmethodFactors affecting the sequence of characters

Rotation.

Overlapping.

Obstacle such as straight line.

Distributed Noise.

Character Colour.

Background Colour.

Scaling.

Font.

Special Character.

Background Texture.

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Proposedmethod - Captcha schemes

Scheme 1:

3D CAPTCHA with rotation.

All characters contain a same

colour.

Each character is rotated in an

individual angle.

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Scheme 2:

3D CAPTCHA with

overlapping characters.

Characters often cause a

segmentation problem.

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Scheme 4:

3D CAPTCHA are with

distributed noise of characters.

Reduction of image clarity.

Noise colour is same as the

colour of the character.

Pixel noise is randomly

generated.

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Scheme 5:

3D CAPTCHA with rotation

and colour background.

Colour of text is generated

randomly, that would contrast

sufficiently with the background

colour, to ensure legibility.

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Scheme 6:

3D CAPTCHA with rotation

and character colour variation.

Attract user and improve

usability.

Colour is randomly generatedfrom RGB components.

Makes CAPTCHA challenges

interesting.

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Scheme 7:

3D CAPTCHA with rotation and

character scaling.

Scaling is performed individually

in each axis.

Scale value is randomly selected to

perform a half or double in length.

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Scheme 8:

3D CAPTCHA with rotation and

font variation.

Font can be broadly divided into

serif and sans-serif fonts.

Some characters of serif font have

unique features for certain

characters that make recognition

easier.

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Scheme 9:

3D CAPTCHA with special

characters.

Use of special character

increases resistance.

Ex:[!, @, #, $, %, &, *, +, ?]

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Scheme 10:

3D CAPTCHA with

background texturecomposed of random

primitives .

Cleverly makes use of the

unique capabilities of human

visual systems.

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Results

Screenshot of evaluation website

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Results

The result of this survey was collected from 138people. The survey was comprised of 10 questions. Asurvey of usability, preference, hit ratio was used tomeasure the efficiency of 3D CAPTCHA.

From the result of the hit ratio, usability, and

preference, scheme 6 (3D CAPTCHA with rotationand character colour variation) is the best from ourten proposed schemes.

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Results - Usability

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Results - Preference

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Results Hit Ratio

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Conclusion

We propose a new generation of the CAPTCHA method that

uses 3D character instead of 2D character.

The advantage of using 3D characters in the CAPTCHA is, it

can be recognizable by human users and difficult to read by

bots.

Our new 3D CAPTCHA method uses a same input method

as that of several other websites using 2D.

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Conclusion

3D CAPTCHA is More secure.

Can increase the rate of its difficulty by applying other

effects such as increase the length of the CAPTCHA,

increase the rotation angle, or include more special

characters.

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Reference

Spamfizzle, http://spamfizzle.com/CAPTCHA.aspx.

CNET news, http://news.cnet.com/8301-17938_105-

10204300-1.html.

ABBYY FineReader 10, http://finereader.abbyy.com
http://spamfizzle.com/CAPTCHA.aspxhttp://news.cnet.com/8301-17938_105-10204300-1.htmlhttp://news.cnet.com/8301-17938_105-10204300-1.htmlhttp://news.cnet.com/8301-17938_105-10204300-1.htmlhttp://news.cnet.com/8301-17938_105-10204300-1.htmlhttp://news.cnet.com/8301-17938_105-10204300-1.htmlhttp://news.cnet.com/8301-17938_105-10204300-1.htmlhttp://news.cnet.com/8301-17938_105-10204300-1.htmlhttp://news.cnet.com/8301-17938_105-10204300-1.htmlhttp://news.cnet.com/8301-17938_105-10204300-1.htmlhttp://spamfizzle.com/CAPTCHA.aspx

3d captcha 1

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