Sketch-Based Password Authentication Using Edge Orientation Patterns

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Solution Overview

Problem

Traditional knowledge-based authentication mechanisms, such as PINs and text-based passwords, are vulnerable due to their complexity and predictability, while graphical password schemes face issues like longer creation and login times and user tolerance for accuracy.

Innovation Solution

A sketch-based graphical password authentication technique, 'Scribble-a-Secret', uses edge orientation patterns from user sketches to authenticate users, allowing for flexible matching and robustness against distortions, suitable for devices with stylus input like PDAs and Tablet PCs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional knowledge-based authentication mechanisms (PINs and text-based passwords) are used, then the system is simple to implement, but the security is weak and passwords become predictable

Engineering Contradiction:
Improveauthentication securityVSAvoidpassword memorability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent uses graphical copies of real-world objects (photos, drawings, sketches) as password elements instead of text-based passwords. Users select and remember visual representations of objects they recognize, leveraging the picture superiority effect where images are easier to recall than text. This resolves the contradiction by providing secure authentication through memorable visual cues rather than predictable text sequences.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent incorporates visual variations in graphical password elements, including different colors, styles, and representations of the same object. This allows users to create distinctive and memorable passwords while maintaining security through the complexity and uniqueness of the visual combinations, addressing both security and memorability requirements.

Inventive Principle:
Principle #32Color changes

2Reliability

If graphical password schemes are used to improve memorability, then authentication becomes more secure, but the creation and login time increases

Engineering Contradiction:
Improveauthentication securityVSAvoidpassword creation and login time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the graphical password into multiple independent elements (e.g., individual photos, drawings, or sketches representing different objects or aspects). Users can select and remember these segmented elements more easily than a single complex image, and the system can process them independently during authentication, reducing the time required compared to evaluating entire graphical passwords.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent allows users to provide more graphical elements than strictly necessary for authentication (excessive action), enabling them to create memorable and secure passwords. The system then uses only the essential elements needed for authentication (partial action), balancing security requirements with acceptable authentication time. This resolves the contradiction by allowing users to invest time in creating memorable passwords while the system efficiently processes only the necessary elements.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If locimetric systems based on method of loci are used, then authentication becomes more convenient than pure recall, but users show weak tolerance for accuracy and the learning time increases

Engineering Contradiction:
Improveauthentication convenienceVSAvoidpoint selection accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent uses graphical copies of familiar objects and scenes as password elements, allowing users to authenticate by recognizing and selecting these visual representations. This approach provides the convenience of guided selection (unlike pure recall) while being more forgiving of imprecision, as users can recognize objects even when not precisely locating specific points. The visual nature of the copies allows for flexible matching that tolerates variations in user input.

Inventive Principle:
Principle #26Copying

4Reliability

If drawmetric systems requiring users to draw figures are used, then authentication becomes unique to each user, but users are unable to recreate drawings accurately with correct sequence of strokes

Engineering Contradiction:
Improveauthentication uniquenessVSAvoiddrawing accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent uses pre-provided graphical copies of objects or scenes that users select and remember, rather than requiring users to create drawings from scratch. This maintains authentication uniqueness through the user's selection and memory of specific visual elements, while eliminating the difficulty of accurately recreating complex drawings. The graphical copies serve as reference standards that users can reliably recall and select during authentication.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

Instead of requiring users to create original drawings and hope they match (as in traditional drawmetric systems), the patent inverts the approach by providing the graphical copies in advance and having users select and remember them. This inversion transforms the task from creative production (which is imprecise) to recognition and selection (which is more accurate and reliable), resolving the contradiction between uniqueness and accuracy.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP2260429B1Sketch-based password authentication
Publication Date: 2013.01.23 MICROSOFT CORP
  • EP2260429B1 patent drawingFigure 1
  • EP2260429B1 patent drawingFigure 2
  • EP2260429B1 patent drawingFigure 3

AI summary

A graphical password authentication method is based on sketches drawn by user. The method extracts a template edge orientation pattern from an initial sketch of the user and an input edge orientation pattern from an input sketch of the user, compares the similarity between the two edge orientation patterns, and makes an authentication decision based on the similarity. The edge orientations are quantized, and each edge orientation pattern includes a set of quantized orientation patterns each corresponding to one of the quantized edge orientations. The number of quantized edge orientations, as well as other parameters such as the dimension of the final orientation patterns and acceptance threshold, can be optimized either globally or user-specifically.