Dynamic CAPTCHA Adaptation for Mobile Device Sensors

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Solution Overview

Problem

Traditional CAPTCHAs are challenging for both humans and bots, leading to user frustration and increased bot abuse as they are either too difficult for humans to solve or too easy, allowing farmed accounts and reduced registration rates.

Innovation Solution

A CAPTCHA system that utilizes a sequence of actions based on a device's features such as touchscreen, magnetometer, accelerometer, and camera capabilities, providing feedback and adjusting complexity based on device capabilities and user performance to differentiate human users from automated bots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional CAPTCHA difficulty is increased to prevent bot abuse, then bot resistance is improved, but user completion rate deteriorates

Engineering Contradiction:
Improvebot resistanceVSAvoiduser completion rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The CAPTCHA system dynamically adjusts the sequence of actions based on device capabilities and accuracy metrics. The system transitions from static difficulty levels to dynamic adaptation, where the same CAPTCHA can present different challenges to different users based on their device's sensor accuracy and performance history.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes parameters such as the number of required actions, the specificity of orientation requirements, and the complexity of gestures based on device capabilities. High-accuracy devices receive more challenging parameter sets while lower-accuracy devices receive adjusted parameters that maintain accessibility.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If CAPTCHA complexity is reduced to improve user experience, then user completion rate is improved, but bot resistance deteriorates

Engineering Contradiction:
Improveuser completion rateVSAvoidbot resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system dynamically adapts complexity based on real-time device capability assessment. Rather than using fixed complexity levels, the system adjusts the challenge difficulty to match each device's capabilities, ensuring both user accessibility and bot resistance are maintained simultaneously.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different parts of the CAPTCHA challenge are weighted differently based on device capabilities. High-accuracy devices are challenged on precise orientation and multiple sensors, while lower-accuracy devices are challenged on gesture recognition and touchscreen interactions, creating locally optimized challenges for each device type.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If device-specific customization is implemented to improve accessibility, then ease of operation is improved, but device complexity increases

Engineering Contradiction:
ImproveaccessibilityVSAvoidsystem complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system uses a universal framework that works across all device types by leveraging common mobile device capabilities (touchscreen, accelerometer, gyroscope). Rather than creating device-specific implementations, the system designs challenges that can be executed on any modern mobile device, reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system manages device complexity by dynamically adjusting challenge parameters rather than maintaining separate challenge sets for each device type. This parameter-based approach simplifies the system architecture while still providing customized experiences for different device capabilities.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8826382B2Antibot mechanisms optimized for mobile computing
Publication Date: 2014.09.02 APPLE INC
  • US8826382B2 patent drawing
  • US8826382B2 patent drawing
  • US8826382B2 patent drawing

AI summary

A method of determining whether a response received from an electronic device is generated by a person or by an automated software. The method receives a set of capabilities of the electronic device for detecting a group of actions that include at least a gesture or a device movement. The method selects a set of actions based on the device capabilities. The method sends a request to the electronic device for performing the set of actions in the plurality of actions. The method, based on a result of the set of actions performed on the electronic device, determining whether the set of actions are performed by a human.