Virtual Touch Interface Security via Hardware Virtualization
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Solution Overview
Problem
Existing solutions for securing virtual touch user interfaces on touch-screen-based computing devices are inadequate against malware attacks, as they fail to effectively protect input and display data from kernel-mode and user-mode keyloggers and screen-scraping malware, relying on cryptographic methods and additional hardware that are not universally available.
Innovation Solution
The implementation of a computing device with hardware virtualization features, specifically using a trusted memory service layer (TMSL) to protect touch input data through a protected filter driver and an in-memory display overlay surface, which prevents unauthorized access by malware and eliminates the need for additional hardware or cryptographic protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cryptographic methods and additional hardware are used to protect touch input data, then security against malware attacks is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces cryptographic software-based protection with hardware-based virtualization features. The trusted memory service layer uses processor virtualization capabilities to create isolated memory regions that are inherently protected from unauthorized access, eliminating the need for complex cryptographic protocols and additional security hardware.
Solution Approach 2:
The system uses the processor's own virtualization features to provide security protection. The trusted memory service layer leverages existing hardware capabilities (extended page tables, virtual machine extensions) already present in modern processors, making the system self-protecting without requiring external security modules or additional hardware components.
2Reliability
If cryptographic protection is applied to display data, then security against screen-scraping malware is improved, but processing overhead and energy consumption increase
Solution Approach 1:
The patent replaces energy-intensive cryptographic protection of display data with hardware-based memory isolation. The display overlay surface is rendered in a protected memory region that is inaccessible to unauthorized applications, eliminating the need for continuous cryptographic encryption and decryption operations that consume significant energy.
3Ease of operation
If filter drivers are inserted in the touch input driver stack, then input interception capability is improved, but system stability and security against malicious drivers worsen
Solution Approach 1:
The patent introduces a trusted memory service layer as an intermediary between the touch input hardware and the operating system. This layer uses hardware virtualization to create a secure buffer zone that intercepts touch input data without requiring traditional filter drivers, thereby maintaining input interception capability while avoiding the instability and security risks associated with kernel-mode driver modifications.
4Reliability
If secure enclaves are used to translate touch coordinates, then input security is improved, but device compatibility and complexity increase
Solution Approach 1:
The patent makes security protection universal by using processor virtualization features that are widely available across different processor architectures and operating systems. The trusted memory service layer leverages standard hardware capabilities (such as extended page tables and virtual machine extensions) that exist in most modern processors, ensuring broad device compatibility without requiring proprietary secure enclave hardware.
Data Source
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AI summary
Technologies for secure input and display of a virtual touch user interface include a computing device having a security monitor that may protect memory regions from being accessed by untrusted code. The security monitor may use hardware virtualization features such as extended page tables or directed I/O to protect the memory regions. A protected touch filter driver intercepts requests for touch input and allocates a transfer buffer. The transfer buffer is protected by the security monitor. A touch screen controller may write touch input data into the protected transfer buffer. The touch input data may be shared by the touch filter driver with authorized applications through a protected communication channel. A graphical virtual user interface may be generated by trusted code and rendered into a hardware overlay surface. The user interface may include a virtual keyboard. The security monitor may protect the overlay surface. Other embodiments are described and claimed.