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1. CAPTCHA IMAGINATION: A Robust Image Based CAPTCHA Generation System

3. Full Form

4. Definition

5. Example

6. Applications

7. Types of CAPTCHA

8. Advantages

9. Disadvantages

12. The process usually involves one computer asking a user to complete a simple test which the computer is able to generate and grade.

15. Online Polls.

16. Search Engine Bots.

18. Graphic Based CAPTCHA.

20. Used in Yahoo Messenger Service.

21. It contains only one random character string.

23. Uses 8 characters.

24. Wraping is used to distort.

27. User must find the characteristic that sets the two series apart

30. User listens and enters the spoken word.

31. Helps visually disabled users.

33. It avoids accessing of E-mails by thousands of spammers every day.

34. Fits to theme of the page.

36. Some CAPTCHA images are very difficult to interpret for humans also.

38. Applications are varied– from stopping bots to character recognition & pattern matching.