Chi as Son Slides
Transcript of Chi as Son Slides
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Accessibility andAccessibility and
Graphical PasswordsGraphical PasswordsSonia Chiasson, Alain Forget, Robert Biddle
Carleton University, Ottawa, Canada
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Click-based graphical passwordsClick-based graphical passwords
PassPoints
Cued Click-Points
(CCP)
Persuasive CCP (PCCP)
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Accessibility?Accessibility?
Inaccessible for some user populations Rely on vision
Rely on fine motor control
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Content vs PresentationContent vs Presentation
Semantic content should be separated frompresentation modality Same content linked with different modalities
E.g. Cascading Style Sheets in web design
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Structure of click-basedStructure of click-based
graphical passwordsgraphical passwords
Presentation: Cue System triggers memory of password
Displays image
Selection: Response User provides secret
Clicks on specific area
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Generalized Cue-ResponseGeneralized Cue-Response
Authentication ModelAuthentication Model
Presentation: any cue, any modality Image, text, sound, haptic, video
Response: any user input, any modality Clicking, typing, verbal, gesture, mouse movement
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Example: PassSoundsExample: PassSounds
Cue: Music clip What is an acceptable length?
Response: Click at appropriate time How accurate can users be?
Musicians can synchronize at approximately 250ms
How many clicks?
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PassSounds: SecurityPassSounds: Security
PassPoints: Image size 451x331
5 clicks
Tolerance 19x19 Theoretical passwordspace 1.2 x 1013 43bits
PassSounds: 30-second clip
5 clicks
Tolerance 1 second
Theoretical passwordspace 1.4 x 105 17bits
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Hotspots and PatternsHotspots and Patterns
PassPoints Choose similar
Click-points on animage (hotspots)
Patterns (lines)
Minimize by:
Using several images
Helping selectpasswords
PassSounds Choose points related to
Lyrics
Beats
Sequential order
Minimize by:
Using several clips?
Suggesting clicks? Identifying other
elements in the clip?
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AlternativesAlternatives
Any combination of presentation and response Audio
As a cue to trigger behaviour other than click Haptics
As a cue or as input
Allow users to select their preferred modalitiesfor a given system In-progress
Caution: Cue and response cannot be evaluated in isolation
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SummarySummary
General cue-response authentication Allows for
separation of cue and response
modalities most appropriate for different users
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[email protected]@scs.carleton.ca
http://hotsoft.carleton.ca/securityhttp://hotsoft.carleton.ca/security
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