Authors:
Ian Jermyn, New York University
Alain Mayer, Fabian Monrose, Michael K. Reiter, Bell Labs, Lucent Technologies
Aviel D. Rubin, AT&T Labs--Research
Summary:
This article proposes a different scheme for user authentication. The scheme that allows user to draw a password rather typing in a password. Prior studies show 50% reduction in retention power of words and humans possess an remarkable ability for recalling pictures( lines diagrams / objects).
This scheme uses a grid of squares and the sequence in which the user crosses the grid is used as the password. The advantage of this approach is that unlike text passwords where there is a specific scheme followed in setting the password( there will not be any specific pattern followed by the user. The number of combinations of 12 dots is way to high when compared to textual passwords of length 8.
What constitutes a memorable password? Any memorable text password is set based on the semantic content of the password. Such semantic content is difficult to identify from the DAS.
Discussion:
Interesting idea. This scheme avoids recognition by using grids of squares. This removes errors of recognition.
It would interesting to know if any 2 users have chosen to set the password. The frequency of users getting the same password. My guess is though there are a lot of possibilities of connecting dots, users would choose a pattern that is easy to remember. This could by some alphabets, greek letters, numbers, line diagrams,.. which leaves us with lesser number of variations than originally stated.
Wednesday, March 25, 2009
Tuesday, March 17, 2009
Kinematic Templates: End-User Tools for Content-Relative Cursor Manipulations
Author:
Richard Fung, Edward Lank, Michael Terry,
David R. Cheriton School of Computer Science, University of Waterloo
Celine Latulipe,
Department of Software and Information Systems, University of North Carolina at Charlotte
Summary:
This paper discusses about kinematic templates, a cursor manipulation method that help users draw strokes. Initial analysis on 2 artist drawings showed that the artists use 2 types of strokes fine, controlled motor movements and coarse movements.
Drawing a sun – A conduroy template is used to draw straight, parallel line and sandpaper template to keep stroke within predefined circular region. 'dimple chad' template to guide lines from one point to the other. The strength of the manipulation depends on the templates chosen – active / passive templates. Passive templates vary control ratio and active templates represent functions that actively apply forces for changing the pointing devices independent of the cursor movement.
End-user interface:
Authoring,editing and attenuating templates:
involves creating an instance of template. This template gets added to the 'list of instantiated templates'. User can switch it ON/OFF according to the needs. The template can be moved by non-dominant hand.
Visual feedback: The template provides visual cues on what the changes would be when the cursor is hovered over the template.
Actively working against templates:
Discussion:
Need to read it once more. I like to know how comfortable are the user when their cursor position changes according to some function that they do not understand. Does the current pointer change according to template / does it change the set of points previous to the stroke?
Saturday, March 14, 2009
Issues in User Authentication
Sonia Chiasson, Robert Biddle, Carleton University
Ottawa, Ontario, CANADA
Summary:
This paper describes some alternate methods for text based password.
Password Manager: User has to enter a single master password to get access to all the other passwords. The user study of 26 people showed their inaccurate mental models of the password manager and the password itself which caused serious errors.
Mental models: The user interface should convey enough information to be able to predict and understand.
Persuasive technology: The password technology must also be persuasive. Most of the times, the problem comes from the unmotivated user.
Identity theft: Other major problem is identity theft (e.g. phishing). Using the identity of the user for fraudulent purposes.
Discussion:
This paper gives an overview of the certain important problems with user authentication.
Scribble-a-Secret: Similarity-Based Password Authentication Using Sketches
Authors:
Mizuki Oka, Kazuhiko Kato, University of Tsukuba
Yingqing Xu, Lin Liang, Fang Wen, Microsoft Research Asia
Summary:
A graphical password scheme which allows user to sketch a password( sequence of strokes does not matter).
Edge Orientation Pattern feature: This feature is known for its robustness in recognition. It accommodates change in direction and spatial orientation. The image captured from user input is characterized by R orientations and then reduced to N orientations. Larger R results in less robustness. So it is reduced to N which is trade off between variation capturing and robustness.
Template creation: The templates are matched to user data using correlation factor. Given a set of edge orientation pattern, the correlation factor with the template is calculated.
The evaluation was done using 87 users. The effectiveness of edge orientation and blurring were studied. The false +ve and -ve rates were studied.
Disccusion:
The scheme looks similar to the Brendon's idea of searching photos with Annotation. Why not show the user an image he knows and ask him to draw a sketch . Can this be used as the password?
About this idea, there are a lot of things that needs to be measured. How many passwords can a user remember at a time? Average(time) retaining power of the user, time to set up a password, variations in password set by single user,...
Mizuki Oka, Kazuhiko Kato, University of Tsukuba
Yingqing Xu, Lin Liang, Fang Wen, Microsoft Research Asia
Summary:
A graphical password scheme which allows user to sketch a password( sequence of strokes does not matter).
Edge Orientation Pattern feature: This feature is known for its robustness in recognition. It accommodates change in direction and spatial orientation. The image captured from user input is characterized by R orientations and then reduced to N orientations. Larger R results in less robustness. So it is reduced to N which is trade off between variation capturing and robustness.
Template creation: The templates are matched to user data using correlation factor. Given a set of edge orientation pattern, the correlation factor with the template is calculated.
The evaluation was done using 87 users. The effectiveness of edge orientation and blurring were studied. The false +ve and -ve rates were studied.
Disccusion:
The scheme looks similar to the Brendon's idea of searching photos with Annotation. Why not show the user an image he knows and ask him to draw a sketch . Can this be used as the password?
About this idea, there are a lot of things that needs to be measured. How many passwords can a user remember at a time? Average(time) retaining power of the user, time to set up a password, variations in password set by single user,...
Saturday, March 7, 2009
Fluid Inking: Augmenting the Medium of Free-Form Inking with Gestures
Authors: Robert Zeleznik,Timothy Miller from CS Dept, Brown University.
Summary:
Three areas that this paper concentrates on - Pen based menu interaction, gesturing while inking and gestures and widgets.
Pen based menu interaction: The press and hold interaction is used to invoke menus. The user should hold till a timeout (500ms). This may be reduced when pressure exceeds a threshold.Gestural shortcuts are similar to CTRL / ALT keys. A flick or a terminal punctuation(pause) is used for triggering shortcuts. The menus can be copies / torn off as buttons to facilitate repetitive actions(Tear - off shortcuts). Gesture sequence and context is used to differentiate similar tokens.
Self contained gestures: Examples are paste(L), select and delete gestures.
Mnemonic punctuates gestures - 'C' gesture can be confused with 'Cut' / 'Copy' functionality, so a longer form both these commands are provided. 'C' and 'X' are shorter versions and 'Copy' / 'Cut' mnemonics are made available.
Mimetic punctuated gestures - mimetic action is marking menus of the flowMenu, just that the menu does not appear on the screen. Example: User draws a stroke hook on the NE direction of the lasso( selecting stroke gesture), since the cut menu appears in the NE direction of the flowMenu. The menu doesnot appear on the screen but the position of the stroke hook corresponds to the 'Cut' menu in the flow Menu list.
Feedback: 2 mechanisms of feedback
* Verbose Feedback - The gesture strokes are different in color and there are text prompts on the screen on the possible set of gestures that can follow.
* Subdued feedback - Different color patterns are followed for non - gesture strokes, incomplete gestures and completed gestures.
Widgets - Widget is provided at tap location for scaling and dragging. At time, this causes problems, when users accidentally pass through the widget causing inadvertent drags / when users miss widget target.
Discussion:
this paper has listed almost all the possible methods of interacting in the pen based input scenario.I need to go through this once more.
Summary:
Three areas that this paper concentrates on - Pen based menu interaction, gesturing while inking and gestures and widgets.
Pen based menu interaction: The press and hold interaction is used to invoke menus. The user should hold till a timeout (500ms). This may be reduced when pressure exceeds a threshold.Gestural shortcuts are similar to CTRL / ALT keys. A flick or a terminal punctuation(pause) is used for triggering shortcuts. The menus can be copies / torn off as buttons to facilitate repetitive actions(Tear - off shortcuts). Gesture sequence and context is used to differentiate similar tokens.
Self contained gestures: Examples are paste(L), select and delete gestures.
Mnemonic punctuates gestures - 'C' gesture can be confused with 'Cut' / 'Copy' functionality, so a longer form both these commands are provided. 'C' and 'X' are shorter versions and 'Copy' / 'Cut' mnemonics are made available.
Mimetic punctuated gestures - mimetic action is marking menus of the flowMenu, just that the menu does not appear on the screen. Example: User draws a stroke hook on the NE direction of the lasso( selecting stroke gesture), since the cut menu appears in the NE direction of the flowMenu. The menu doesnot appear on the screen but the position of the stroke hook corresponds to the 'Cut' menu in the flow Menu list.
Feedback: 2 mechanisms of feedback
* Verbose Feedback - The gesture strokes are different in color and there are text prompts on the screen on the possible set of gestures that can follow.
* Subdued feedback - Different color patterns are followed for non - gesture strokes, incomplete gestures and completed gestures.
Widgets - Widget is provided at tap location for scaling and dragging. At time, this causes problems, when users accidentally pass through the widget causing inadvertent drags / when users miss widget target.
Discussion:
this paper has listed almost all the possible methods of interacting in the pen based input scenario.I need to go through this once more.
A mark-based interaction paradigm for free-hand drawing
Author:Thomas Baudel
Summary:
This paper gives a different view of editing splines. This paper claims this method of editing splines is more closer to our interaction model than the editing splines with control points and tangents.
This method is very suitable for the graphical designers (closer to their conceptual model). Sketch recognition is used to provide complex modifications and re parametrization.
The method can decomposed into 2 operations:
Given a first F and second m,
1. find the starting point S and end point E that would match best with m. These points are found by finding the visually closest points on F from m. Equal length matching is done and a list of all possible candidate curves are maintained for the user to choose. This search can be further optimized. When the curves are discretized to poly-lines, the search is reduced to the number of poly-lines.
2. Transform F(SE) into r (the resulting stroke) with the help of m. This method encourages for large imprecise strokes and short n fast strokes which start and end within the curve F.First f and m are converted into poly-lines and the resulting curve r is a poly-line which will be smoothed. The algorithm defines a smoothness factor 'k' and a transitional polynomial to provide smoothness in transition. An extension segment each at the start(S') and at the end(E') of curve F is defined for smooth transition between S' -> S and E->E' while re - parametrization.
Evaluation this method showed this method needed lesser effort from the user for editing.
This method allows complex re-parametrization in one single action rather than specifying lot of control points.
Future Work: Use of pressure information to re-parametrize the width/ density of the stroke.
Discussion:
This is a totally different approach to the problem of editing strokes. But it requires a mode switch to understand which stroke is the base stroke and which one is (m) stroke that edits the previous one.
I would like to know how this algorithm be applied when there is no mode switch. There would be a problem of identifying (m). For every stroke drawn by the user, should the next stroke be considered the editing stroke(m)/ should it based on some distance threshold?. Would the user like the automatic adjustments?
I do not think there would any necessity to re-parametrize strokes width. I do not think the editing stroke captures the user-intended width. So the re-parametrized stroke should have the same density pattern as the original stroke.
Summary:
This paper gives a different view of editing splines. This paper claims this method of editing splines is more closer to our interaction model than the editing splines with control points and tangents.
This method is very suitable for the graphical designers (closer to their conceptual model). Sketch recognition is used to provide complex modifications and re parametrization.
The method can decomposed into 2 operations:
Given a first F and second m,
1. find the starting point S and end point E that would match best with m. These points are found by finding the visually closest points on F from m. Equal length matching is done and a list of all possible candidate curves are maintained for the user to choose. This search can be further optimized. When the curves are discretized to poly-lines, the search is reduced to the number of poly-lines.
2. Transform F(SE) into r (the resulting stroke) with the help of m. This method encourages for large imprecise strokes and short n fast strokes which start and end within the curve F.First f and m are converted into poly-lines and the resulting curve r is a poly-line which will be smoothed. The algorithm defines a smoothness factor 'k' and a transitional polynomial to provide smoothness in transition. An extension segment each at the start(S') and at the end(E') of curve F is defined for smooth transition between S' -> S and E->E' while re - parametrization.
Evaluation this method showed this method needed lesser effort from the user for editing.
This method allows complex re-parametrization in one single action rather than specifying lot of control points.
Future Work: Use of pressure information to re-parametrize the width/ density of the stroke.
Discussion:
This is a totally different approach to the problem of editing strokes. But it requires a mode switch to understand which stroke is the base stroke and which one is (m) stroke that edits the previous one.
I would like to know how this algorithm be applied when there is no mode switch. There would be a problem of identifying (m). For every stroke drawn by the user, should the next stroke be considered the editing stroke(m)/ should it based on some distance threshold?. Would the user like the automatic adjustments?
I do not think there would any necessity to re-parametrize strokes width. I do not think the editing stroke captures the user-intended width. So the re-parametrized stroke should have the same density pattern as the original stroke.
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