Secure Touchpanel Data Entry via TEE Segmentation
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Solution Overview
Problem
Current virtual keypad layouts on touchpanel displays for payment terminals face security threats due to open mode firmware controlling the LCD interface, which lacks adequate protection against hackers accessing sensitive data, and existing solutions like signed screenshots restrict user interface customization and do not meet industry certification standards.
Innovation Solution
A method that monitors touchpanel LCD usage by receiving interaction positions, determining if secure data is present, assessing previous interactions, and asserting security threats, allowing secure data entry without impacting third-party developers, using a Trusted Execution Environment (TEE) for security-related firmware and a Rich Execution Environment (REE) for applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If open mode firmware controls the LCD interface to allow full user interface customization, then ease of operation and adaptability are improved, but security is worsened due to potential hacker access to sensitive data
Solution Approach 1:
The system divides the firmware into two separate modes: open mode for general application development and secure mode for security-critical operations. This segmentation allows the LCD interface to be fully customizable in open mode while isolating security functions in secure mode, thus resolving the contradiction between adaptability and security.
Solution Approach 2:
A TEE interface acts as an intermediary between open mode and secure mode. The TEE (Trusted Execution Environment) provides a secure channel for communication, allowing open mode applications to request secure operations without directly accessing sensitive data or secure mode firmware, thus maintaining both customization freedom and security.
2Reliability
If signed LCD screenshots are used to enforce secure display, then security is improved, but ease of manufacture and adaptability are worsened due to restrictions on interface design freedom
Solution Approach 1:
The TEE interface serves as an intermediary that enables secure data entry without requiring signed screenshots. It provides a controlled interface for secure operations while allowing full flexibility in LCD display design, thus achieving security without restricting interface design freedom.
Solution Approach 2:
The patent replaces the mechanical approach of signed screenshots (a static, restrictive verification method) with a software-based TEE interface that dynamically manages security. This substitution eliminates the need for signed screenshots while maintaining security, thus improving ease of manufacture and interface design freedom.
3Reliability
If physical keypads with mechanical switches are used, then security is improved through hardware protection, but device complexity and ease of manufacture are worsened compared to virtual keypads
Solution Approach 1:
The patent replaces mechanical keypads with virtual keypads displayed on an LCD touch panel. Security is maintained not through mechanical hardware protection but through software-based TEE (Trusted Execution Environment) that provides secure processing of PIN entries and sensitive data, thus reducing device complexity while maintaining security.
Solution Approach 2:
The system changes the fundamental parameter of keypad implementation from mechanical (physical switches) to electronic (software-based touch interface). Security is enforced through parameter changes in the execution environment (TEE vs. REE) rather than through physical hardware constraints, thus simplifying the device structure while maintaining security.
Data Source
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AI summary
A method for secure data entry on an interface, the method comprising: receiving (100) a position of an interaction with the interface; determining (101) whether secure data is present in an area around the position; assessing (102) a number of interactions, n previous to the current interaction for secure data; and if secure data is present in the area and n interactions preceding the user interaction comprises secure data, asserting (104) that the user interaction comprises a security threat.