Secured KVM Switching Device with Unidirectional Optical Isolation
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Solution Overview
Problem
KVM switches face security threats due to bidirectional communication, which can allow malicious code to spread between connected computers, and existing solutions fail to adequately address the issue of differing monitor settings across multiple computers.
Innovation Solution
A secured switching apparatus (SKVM) with galvanic isolation and unidirectional communication using optical fibers to prevent stray currents and block bidirectional signals, allowing a single keyboard and display device to control multiple computers while isolating communication and reading/video settings to prevent unauthorized access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bidirectional communication is implemented in KVM switch, then control functionality is improved, but security risk increases due to malicious code transmission
Solution Approach 1:
The patent divides the communication path into separate unidirectional channels using optical fibers. The video signal path (computer to display) is separated from the control signal path (display to computer), with each direction using dedicated optical fibers. This segmentation prevents bidirectional communication while maintaining control functionality.
Solution Approach 2:
The patent introduces an intermediary conversion system that transforms electrical signals from computers into optical signals for transmission to the display, and vice versa. This intermediary conversion process isolates the computer from direct electrical connection to the display, blocking malicious code transmission while preserving control capabilities.
2Object-affected harmful factors
If optical fiber unidirectional communication is used, then security is improved by blocking malicious code, but communication isolation complexity increases
Solution Approach 1:
The patent replaces traditional electrical signal transmission with optical fiber transmission. By substituting electrical fields with optical fields, the system achieves inherent unidirectional communication and galvanic isolation without requiring complex electrical isolation circuits or multiple isolation stages.
Solution Approach 2:
The patent makes the optical fiber infrastructure serve multiple functions: it transmits video signals in one direction, control signals in the opposite direction, provides galvanic isolation, and enables unidirectional communication all simultaneously. This multi-functionality reduces overall system complexity despite the security enhancements.
3Object-affected harmful factors
If galvanic isolation is implemented, then stray current blocking is improved, but device structure complexity increases
Solution Approach 1:
The patent replaces electrical signal transmission with optical signal transmission using fibers. This substitution inherently provides galvanic isolation since optical fibers do not conduct electricity, eliminating the need for additional galvanic isolation components and simplifying the overall device structure.
4Adaptability or versatility
If monitor settings are read from connected computers, then display compatibility is improved, but security vulnerability increases
Solution Approach 1:
The patent performs monitor settings configuration in advance during system setup. The display characteristics and parameters are pre-configured and stored in the display device's memory before connecting to different computers. This preliminary action eliminates the need for real-time settings exchange, blocking malicious code transmission while maintaining display compatibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The SKVM effectively prevents malicious code transmission and ensures secure control of multiple computers by blocking bidirectional communication and isolating electrical circuits, thereby enhancing security and compatibility with diverse monitor settings.
Implementation Method 1
allowing the communication to flow in one direction by utilizating a physical layer which blocks the communication signals from flowing in the opposite direction
Implementation Method 2
a galvanic isolation which blocks stray currents from passing between the SKVM circuits
Data Source
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AI summary
A unidirectional KVM device, comprising: a device emulator connected to a keyboard interface and a pointing device interface of a computer, and a video connection connected to a video interface from said computer, said device emulator receives keyboard and pointing device communication signals through an optical fiber and transmits keyboard signals and pointing device signals to said keyboard interface and pointing device interface, said video connection receives video stream from video interface of said computer and transmits said video streaming through an optical fiber, a controller-and-host-emulator coupled with a keyboard interface and a pointing device interface; a serial-to-HDMI unit receives the video stream from said computer through said optical fiber, and transmits said serial video stream via said video interface to the user display device, said controller-and-host-emulator receives keyboard and pointing device communication signals, and transmit said communication signals to said device emulator through an optical fiber.