The document discusses and compares various authentication methods, including recognition-based, recall-based, and graphical password techniques. It provides an overview of common techniques such as Dhamija and Perrig's picture selection scheme, Sobrado and Birget's pass-object selection scheme, and Jermyn et al.'s Draw-A-Secret scheme. While graphical passwords may be easier for users to remember than text passwords, they have limitations such as taking longer to create and register, requiring more storage space, and not being very mature yet compared to traditional text-based passwords. The document evaluates the security and usability of different authentication methods.

1. Presented by: M.Bhargavi 08Q61A0558

2. Introduction Overview of the Authentication Methods The survey Recognition Based Techniques Recall Based Techniques Discusssion Security Usability Conclusion

3. How about text-based passwords ? Difficulty of remembering passwords easy to remember -> easy to guess hard to guess -> hard to remember Users tend to write passwords down or use the same passwords for different accounts An alternative: Graphical Passwords Psychological studies: Human can remember pictures better than text

4. If the number of possible pictures is sufficiently large, the possible password space may exceed that of text-based schemes, thus offer better resistance to dictionary attacks . can be used to: workstation web log-in application ATM machines mobile devices

5. Conduct a comprehensive survey of the existing graphical password techniques Discuss the strengths and limitations of each method Point out future research directions

6. Token based authentication key cards, band cards, smart card, … Biometric based authentication Fingerprints, iris scan, facial recognition, … Knowledge based authentication text-based passwords, picture-based passwords, … most widely used authentication techeniques

7. Recognition Based Techniques a user is presented with a set of images and the user passes the authentication by recognizing and identifying the images he selected during the registration stage Recall Based Techniques A user is asked to reproduce something that he created or selected earlier during the registration stage

8. Dhamija and Perrig Scheme Pick several pictures out of many choices, identify them later in authentication. using Hash Visualization, which, given a seed, automatically generate a set of pictures take longer to create graphical passwords password space: N!/K! (N-K)! ( N-total number of pictures; K-number of pictures selected as passwords)

9. Sobrado and Birget Scheme System display a number of pass-objects (pre-selected by user) among many other objects, user click inside the convex hull bounded by pass-objects. authors suggeated using 1000 objects, which makes the display very crowed and the objects almost indistinguishable. password space: N!/K! (N-K)! ( N-total number of picture objects; K-number of pre-registered objects)

10. Other Schemes Using human faces as password Select a sequence of images as password

11. Draw-A-Secret (DAS) Scheme User draws a simple picture on a 2D grid, the coordinates of the grids occupied by the picture are stored in the order of drawing redrawing has to touch the same grids in the same sequence in authentication user studies showed the drawing sequences is hard to Remember

12. “ PassPoint” Scheme User click on any place on an image to create a password. A tolerance around each chosen pixel is calculated. In order to be authenticated, user must click within the tolerances in correct sequence. can be hard to remember the sequences Password Space: N^K ( N -the number of pixels or smallest units of a picture, K - the number of Point to be clicked on )

13. Other Schemes Grid Selection Scheme Signature Scheme

14. Using distorted images to prevent revealing of passwords Using images with random tracks of geometric graphical shapes

15. Is a graphical password as secure as text-based passwords? text-based passwords have a password space of 94^N (94 – number of printable characters, N- length of passwords). Some graphical password techniques can compete: Draw-A-Secret Scheme, PassPoint Scheme. Brute force search / Dictionary attacks The attack programs need to automatically generate accurate mouse motion to imitate human input, which is more difficult compared to text passwords. Guessing Social engineering …

16. Pictures are easier to remember than text strings Password registration and log-in process take too long Require much more storage space than text based passwords

17. main argument for graphical passwords: people are better at memorizing graphical passwords than text-based passwords It is more difficult to break graphical passwords using the traditional attack methods such as:burte force search, dictionary attack or spyware. Not yet widely used, current graphical password techniques are still immature