Understanding CAPTCHA: Types, Purpose, and Applications, Slides of Computer Security

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CAPTCHA

A Seminar On:

Contents

• (^) Introduction
• (^) Purpose of CAPTCHA
• (^) How a CAPTCHA created..?
• (^) Types of CAPTCHA
• (^) Breaking CAPTCHA
• (^) Application
• (^) Benefits
• (^) Drawbacks
• (^) Conclusion
• (^) References

Purpose of using CAPTCHA:

• (^) This technology is used mostly to block spammers and bots that try to automatically harvest email addresses or try to automatically sign up for a make use of web sites, blogs or forums.
• (^) CAPTCHA, whose user include Yahoo and Google, blocks automated systems, which can’t read the distorted letters in the graphic.

How to create and use a CAPTCHA:

• (^) A CAPTCHA image shows a random string which the user has to type to submit a form. This is simple problem for humans, but a very hard problem for computes which have to use character recognization, especially, because the displayed string is alienated in a decode.
• (^) To use this technology, your web pages have to be generated dynamically in any programming language. PHP ASP Peri Python JSP Apex Ruby

Types cont...

2. Picture identification of captcha Create a large database of labeled images Pick a concrete object Pick images of object from the images database Distort the images and ask the user to pick the object for a list of words  (^) This captcha provides users for selecting the elementary choice of selecting the correct image that they are asked to identify.

Types cont...

3.Math Solution

• (^) This type of captcha involves basic math problems and if your user cannot solve this basic questions then probably you do not want them to visit your website further. This provides with easy to read numbers and must be solved to get through the captcha. 4.3D captcha
• (^) These type of captchas are called as “Super Captcha” because there are several 3D images which include both images and words and thus becomes hard for one to solve it.

Types cont...

7.Drag and drop Captcha

• (^) This is also one of the easy to use captchas. It is jQuery based which allows user to drag the required object or shape to pass through the security gate 8.Tic Tac Toe Captcha
• (^) This captcha which involves gamification was designed for fun and an easy way to ensure that only humans can interact with your website. The captcha that does not hurt that much.

Types cont...

9. Audio based captcha:

• (^) Pick a word or a sequence of numbers at random
• (^) Render them into an audio clip using a TTS software
• (^) Distort the audio clip
• (^) Ask the user to identify and type the word or number.

Application:

• (^) Preventing comment spam in blogs
• (^) Protecting website registration
• (^) Protecting email addresses from scrapers
• (^) Online polls
• (^) Preventing dictionary attacks

Benefits:

• (^) The database already exists and is public
• (^) The database is constantly being updated and maintained
• (^) Adding “concrete objects” to the dictionary is virtually instantaneous
• (^) Distortion prevents caching hacks
• (^) Quick expiration limits streaming hacks

Conclusion:

• (^) CAPTCHA are any software that distinguishes human and machine.
• (^) Research in CAPTCHAS implies advancement in AI making computers understand how human thinks.
• (^) Internet companies are making billions of dollar every year, their security and services quality matters and so does the advancement in CAPTCHA technology.
• (^) Different methods of CAPTCHAS are being studied but new ideas like ReCAPTCHA using human time on amazing.

References:

• (^) www.google.com
• (^) www.researchgate.net
• (^) https://captcha.com
• (^) www.letsnurture.com
• (^) www.quora.com