CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK
-
Upload
camden-leblanc -
Category
Documents
-
view
45 -
download
0
description
Transcript of CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK
![Page 1: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/1.jpg)
CAPTCHACAPTCHA: ARE U A HUMAN: ARE U A HUMANSORRY I HAD TO SORRY I HAD TO
ASKASK
Pranaya Priyankar Mishra
B.Tech(CSE)Roll:06165GITA
![Page 2: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/2.jpg)
AGENDAAGENDAWhat is CAPTCHA?Types of CAPTCHAWhere to use CAPTCHAs?Guidelines when making a
CAPTCHAWays to break CAPTCHAsreCAPTCHAHuman Computation Games
![Page 3: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/3.jpg)
AGENDAAGENDAWhat is CAPTCHA?Types of CAPTCHAWhere to use CAPTCHAs?Guidelines when making a
CAPTCHAWays to break CAPTCHAsreCAPTCHAHuman Computation Games
![Page 4: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/4.jpg)
CAPTCHACAPTCHA
Completely Automated Public Turing test to tell Computers and Humans Apart
![Page 5: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/5.jpg)
BEGININGS. . . . .BEGININGS. . . . .
Created in 2000 for Yahoo to prevent automated e-mail account registration,
by Luis von Ahn, Manuel Blum, Nicholas Hopper and John Langford in Carnegie Mellon University.
![Page 6: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/6.jpg)
LUIS VON AHN (LUIS VON AHN (1978 1978 - )- )
![Page 7: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/7.jpg)
What is CAPTCHA?What is CAPTCHA?
A program that can tell whether its user is a human or a computer.
It uses a type of challenge-response test to determine that the response is not generated by a computer.
![Page 8: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/8.jpg)
TURING TESTTURING TEST
„Standard Interpretation"
player C, the interrogator, is tasked with trying to determine which player - A or B - is a computer and which is a human.
![Page 9: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/9.jpg)
REVERSE TURING TESTREVERSE TURING TEST
A CAPTCHA is sometimes described as a reverse Turing test, because it is
administered by a machine and targeted to a human.
![Page 10: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/10.jpg)
So, CAPTCHA is…So, CAPTCHA is…
A program that can generate and grade tests that:
Most humans can pass;Current computer programs cannot
pass.
![Page 11: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/11.jpg)
AGENDAAGENDAWhat is CAPTCHA?Types of CAPTCHAWhere to use CAPTCHAs?Guidelines when making a
CAPTCHAWays to break CAPTCHAsreCAPTCHAHuman Computation Games
![Page 12: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/12.jpg)
TYPE:EARLY CAPTCHATYPE:EARLY CAPTCHAGenerated by the EZ-Gimpy and
Gimpy programUsed previously on Yahoo!
![Page 13: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/13.jpg)
Type: Improved Type: Improved CAPTCHA CAPTCHA
high contrast for human readability; medium, per-character perturbation; random fonts per character; low background noise;
![Page 14: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/14.jpg)
Type: A modern Type: A modern CAPTCHACAPTCHA
rather than attempting to create a distorted background and high levels of warping on the text;
focus on making segmentation difficult by adding an angled line;
![Page 15: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/15.jpg)
Type: A modern Type: A modern CAPTCHACAPTCHA
another way to make segmentation difficult is to crowd symbols together;
this can be read by humans but cannot be segmented by bots;
![Page 16: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/16.jpg)
Other Types of Other Types of CAPTCHACAPTCHAAnimated CAPTCHAs
3D CAPTCHA
ASCII art
Reverse CAPTCHA "Leave this field blank"
![Page 17: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/17.jpg)
OTHER………OTHER………
Distinguish pictures of dogs from catsVisual Puzzle(BONGO)Choose a word that relates to all the
images(PIX)Trivia questions Math and word problems 3D Object CAPTCHASolve failed OCR inputs(reCAPTCHA)Audio CAPTCHAVideo CAPTCHA
![Page 18: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/18.jpg)
Other: Distinguish Other: Distinguish picturespictures Microsoft Asirra (Animal Species Image
Recognition for Restricting Access); KittenAuth Project .
![Page 19: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/19.jpg)
OtherOther: : Mathematical Mathematical CAPTCHA CAPTCHA
![Page 20: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/20.jpg)
Other: 3D Object Other: 3D Object CAPTCHACAPTCHA
You must enter them in the exact sequence listed:
• The Head of the Walking Man,
• The Vase,• The Back of the
Chair.
![Page 21: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/21.jpg)
AGENDAAGENDAWhat is CAPTCHA?Types of CAPTCHAWhere to use captchas?Guidelines when making a
CAPTCHAWays to break CAPTCHAsreCAPTCHAHuman Computation Games
![Page 22: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/22.jpg)
WHERE TO USE CAPTCHAsWHERE TO USE CAPTCHAs
Worms and SpamPreventing Comment Spam in BlogsProtecting Email Addresses From
ScrapersOnline PollsProtecting Website RegistrationPreventing Dictionary AttacksSearch Engine BotsBook Digitization
![Page 23: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/23.jpg)
AGENDAAGENDA
What is CAPTCHA?Types of CAPTCHAWhere to use CAPTCHAs?Guidelines when making a
CAPTCHAWays to break CAPTCHAsreCAPTCHAHuman Computation Games
![Page 24: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/24.jpg)
GUIDELINES……GUIDELINES……
Image SecurityScript Level Security.Security Even After Wide-Spread
AdoptionAccessibility.(Implement Audio
Captcha)
![Page 25: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/25.jpg)
GUIDELINES:GUIDELINES: ACCESIBILITYACCESIBILITYWorst CAPTCHAs:
![Page 26: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/26.jpg)
AGENDAAGENDAWhat is CAPTCHA?Types of CAPTCHAWhere to use CAPTCHAs?Guidelines when making a
CAPTCHAWays to break CAPTCHAsreCAPTCHAHuman Computation Games
![Page 27: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/27.jpg)
Ways to break CAPTCHAsWays to break CAPTCHAs
Exploiting bugs in the implementation that allow the attacker to completely bypass the CAPTCHA;
Improving Character Recognition software (OCR – Optical Character Recognition );
Using cheap human labor to process the tests (sweatshops).
![Page 28: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/28.jpg)
BreakBreak: Character : Character RecognitionRecognition
Programs that have the following functions:◦Extraction of the image from the web page ◦Removal of background clutter, for
example with color filters and detection of thin lines;
◦Segmentation, i.e. splitting the image into regions each containing a single letter;
◦Identifying the letter for each region.
![Page 29: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/29.jpg)
Attacks – Attacks – EZ-Gimpy EZ-Gimpy 20002000 Yahoo's early CAPTCHA called "EZ-Gimpy“; The program picks a word from a
dictionary, and produces a distorted and noisy image of the word;
Algorithm for breaking EZ-Gimpy (92%):
1. Locate possible letters at various locations;
2. Construct graph of consistent letters;
3. Look for plausible words in the graph.
![Page 30: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/30.jpg)
Attacks – Attacks – EZ-Gimpy 2000EZ-Gimpy 2000
EZ-Gimpy
Possible Letters
Graph of Letters
Plausible Words
![Page 31: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/31.jpg)
Attacks – Attacks – SimpleOCR Engine SimpleOCR Engine 20022002
![Page 32: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/32.jpg)
AGENDAAGENDAWhat is CAPTCHA?Types of CAPTCHAWhere to use CAPTCHAs?Guidelines when making a
CAPTCHAWays to break CAPTCHAsreCAPTCHAHuman Computation Games
![Page 33: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/33.jpg)
reCAPTCHA(2007)reCAPTCHA(2007)New form of CAPTCHA that also
helps digitize books;The words displayed to the user
come directly from old books that are being digitized;
Words that OCR could not identify;
![Page 34: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/34.jpg)
reCAPTCHAreCAPTCHA Pairs an unknown word with a known one; Distorts them both and puts a line through
them and then sent them to be proofread; Respondent answers both elements:
• half of effort validates the challenge; • the other half is captured as work.
![Page 35: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/35.jpg)
reCAPTCHAreCAPTCHA
![Page 36: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/36.jpg)
AGENDAAGENDA
What is CAPTCHA?Types of CAPTCHAWhere to use CAPTCHAs?Guidelines when making a
CAPTCHAWays to break CAPTCHAsreCAPTCHAHuman Computation Games
![Page 37: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/37.jpg)
HUMAN COMPUTATION HUMAN COMPUTATION GAMESGAMES
ESP GameTag A Tune GameMatchin GameSquigl GameVerbosity Game
![Page 38: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/38.jpg)
ESP GAMEESP GAMEPlayer 1
Guessing: CARGuessing : HATGuessing: KIDSuccess!You agree on CAR
Player 2
Guessing : BOYGuessing : CARSuccess!You agree on CAR
![Page 39: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/39.jpg)
TAG A TUNE GAMETAG A TUNE GAME
![Page 40: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/40.jpg)
MATCHIN GAMEMATCHIN GAME
![Page 41: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/41.jpg)
SQUIGL GAMESQUIGL GAME
![Page 42: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/42.jpg)
VERBOSITY GAMEVERBOSITY GAME
![Page 43: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/43.jpg)
REFERANCESREFERANCES
www.captcha.netwww.recaptcha.netwww.howstuffworks.comwww.youtube.com
![Page 44: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/44.jpg)
PREDICTIONS……PREDICTIONS……
The CAPTCHA spam arms race will lead to the creation of ARTIFICIAL INTELLIGENCE……
![Page 45: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/45.jpg)
![Page 46: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/46.jpg)
![Page 47: CAPTCHA : ARE U A HUMAN SORRY I HAD TO ASK](https://reader036.fdocuments.in/reader036/viewer/2022062517/568134d5550346895d9bfecd/html5/thumbnails/47.jpg)
QUERIES ? QUERIES ?