Adaptive CAPTCHA Generation for Touchscreen Input Convenience

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Solution Overview

Problem

Current CAPTCHA generation mechanisms on handheld touch screen devices are inconvenient as they often require users to switch between different virtual keyboard types, leading to increased time and effort, especially since not all devices support full-size keyboards, and image recognition CAPTCHAs are costly and less commonly used.

Innovation Solution

A CAPTCHA generation method that adapts to the default virtual keyboard type of the handheld touch screen device, generating CAPTCHAs based on whether the device has an alphabet, numeric, scratchable-latex, or full-size virtual keyboard, eliminating the need for users to switch between keyboard types and simplifying the input process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a standard alpha-numeric CAPTCHA is generated without considering device-specific keyboard types, then the CAPTCHA can be universally applied across different devices, but users on handheld touch screen devices must switch between different virtual keyboard types increasing time and effort

Engineering Contradiction:

ImproveCAPTCHA compatibility across devicesVSAvoidUser input convenience

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent applies local quality by customizing the CAPTCHA character set according to the specific virtual keyboard type detected on the user's device. Instead of using a universal alpha-numeric CAPTCHA, the system generates CAPTCHAs with characters that match the local keyboard layout (e.g., alphabet-only for QWERTY, numeric-only for numeric keyboards, scratchable-latex for specific devices), making each CAPTCHA locally optimized for its target device's input capabilities

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system changes the parameters of the CAPTCHA generation based on the detected virtual keyboard type. The character set parameter is dynamically adjusted according to the device's keyboard capabilities, transforming a static universal CAPTCHA approach into a dynamic adaptive one that modifies its output parameters based on input device characteristics

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If image recognition CAPTCHAs are used instead of text-based CAPTCHAs, then user convenience is improved, but implementation cost increases significantly

Engineering Contradiction:

ImproveUser input convenienceVSAvoidImplementation cost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The patent employs a cost-effective approach by using simple text-based CAPTCHA generation with distorted fonts and character substitutions rather than expensive image recognition technology. The CAPTCHA uses basic rendering techniques that can be implemented with minimal computational resources, providing a disposable, single-use security challenge that doesn't require expensive image processing infrastructure

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The system replaces the mechanical complexity of image recognition and optical character recognition systems with a simpler text rendering approach. Instead of using complex image processing algorithms and hardware, the patent uses software-based font distortion and character substitution techniques that achieve similar security objectives with much lower implementation costs

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10346606B2Generation of a captcha on a handheld touch screen device

Publication Date: 2019.07.09 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Embodiments of the present disclosure relate to a CAPTCHA generation method. According to the method, a request for accessing a resource is received from a handheld touch screen device. A default virtual keyboard type is received from the handheld touch screen device. In response to the request, a CAPTCHA is generated based on the default virtual keyboard type. The CAPTCHA is sent to the handheld touch screen device.