High Sec Labs SK21PH-4,
SK41PH-4, DK22PH-4, DK42PH-
4, SK81PH-4, DK82PH-4,
SX42PH-4, SX82PH-4 Firmware
Version 44404-E7E7 Peripheral
Sharing Devices
Security Target
Doc No: 2149-001-D102A3
Version: 1.0
20 November 2023
High Sec Labs Ltd.
29 HaEshel St
Caesarea,
Israel 3079510
Prepared by:
EWA-Canada, An Intertek Company
1223 Michael Street North, Suite 200
Ottawa, Ontario, Canada
K1J 7T2
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CONTENTS
1 SECURITY TARGET INTRODUCTION.............................................1
1.1 DOCUMENT ORGANIZATION........................................................... 1
1.2 SECURITY TARGET REFERENCE....................................................... 2
1.3 TOE REFERENCE........................................................................... 2
1.4 TOE OVERVIEW............................................................................ 2
TOE Environment ...........................................................................3
1.5 TOE DESCRIPTION ....................................................................... 4
Evaluated Configuration ..................................................................4
Physical Scope ...............................................................................5
Logical Scope.................................................................................6
2 CONFORMANCE CLAIMS...............................................................8
2.1 COMMON CRITERIA CONFORMANCE CLAIM ...................................... 8
2.2 PP-CONFIGURATION CONFORMANCE CLAIM ..................................... 8
2.3 TECHNICAL DECISIONS................................................................. 8
2.4 PACKAGE CLAIM........................................................................... 9
2.5 CONFORMANCE RATIONALE ......................................................... 10
3 SECURITY PROBLEM DEFINITION..............................................11
3.1 THREATS .................................................................................. 11
3.2 ORGANIZATIONAL SECURITY POLICIES ......................................... 12
3.3 ASSUMPTIONS........................................................................... 12
4 SECURITY OBJECTIVES..............................................................14
4.1 SECURITY OBJECTIVES FOR THE TOE ............................................ 14
4.2 SECURITY OBJECTIVES FOR THE OPERATIONAL ENVIRONMENT......... 19
4.3 SECURITY OBJECTIVES RATIONALE............................................... 20
5 EXTENDED COMPONENTS DEFINITION......................................26
6 SECURITY FUNCTIONAL REQUIREMENTS...................................28
6.1 CONVENTIONS........................................................................... 28
6.2 SECURITY FUNCTIONAL REQUIREMENTS........................................ 29
User Data Protection (FDP)............................................................34
Protection of the TSF (FPT)............................................................40
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TOE Access (FTA).........................................................................41
7 SECURITY ASSURANCE REQUIREMENTS ....................................42
8 SECURITY REQUIREMENTS RATIONALE.....................................43
8.1 SECURITY FUNCTIONAL REQUIREMENTS RATIONALE ....................... 43
8.2 DEPENDENCY RATIONALE............................................................ 43
8.3 SECURITY ASSURANCE REQUIREMENTS RATIONALE ........................ 44
9 TOE SUMMARY SPECIFICATION.................................................45
9.1 USER DATA PROTECTION ............................................................ 45
System Controller ........................................................................45
Keyboard and Mouse Functionality..................................................46
Video Switching Functionality.........................................................48
Audio Switching Functionality ........................................................52
9.2 PROTECTION OF THE TSF ............................................................ 54
No Access to TOE .........................................................................54
Anti-tampering Functionality..........................................................54
TSF Testing .................................................................................54
9.3 TOE ACCESS.............................................................................. 55
10 TERMINOLOGY AND ACRONYMS ................................................57
10.1 TERMINOLOGY........................................................................... 57
10.2 ACRONYMS................................................................................ 57
11 REFERENCES..............................................................................59
ANNEX A – LETTER OF VOLATILITY ........................................................1
LIST OF TABLES
Table 1 – Non-TOE Hardware and Software................................................. 4
Table 2 – TOE Peripheral Sharing Devices and Features ................................ 5
Table 3 – Logical Scope of the TOE ............................................................ 7
Table 4 – Applicable Technical Decisions ..................................................... 9
Table 5 – Threats.................................................................................. 12
Table 6 – Assumptions........................................................................... 13
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Table 7 – Security Objectives for the TOE ................................................. 19
Table 8 – Security Objectives for the Operational Environment..................... 20
Table 9 – Security Objectives Rationale .................................................... 25
Table 10 – Functional Families of Extended Components ............................. 27
Table 11 – Summary of Security Functional Requirements........................... 33
Table 12 – Audio Filtration Specifications .................................................. 34
Table 13 – Security Assurance Requirements............................................. 42
Table 14 – Functional Requirement Dependencies ...................................... 44
Table 15 – Terminology ......................................................................... 57
Table 16 – Acronyms............................................................................. 58
Table 17 – References ........................................................................... 59
LIST OF FIGURES
Figure 1 – Evaluated Configuration ............................................................ 4
Figure 2 – Simplified Switching Diagram................................................... 47
Figure 3 – Display EDID Read Function..................................................... 49
Figure 4 – Display EDID Write Function .................................................... 50
Figure 5 – Display Normal Mode .............................................................. 51
Figure 6 – Channel Selection................................................................... 55
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1 SECURITY TARGET INTRODUCTION
This Security Target (ST) defines the scope of the evaluation in terms of the
assumptions made, the intended environment for the Target of Evaluation
(TOE), the Information Technology (IT) security functional and assurance
requirements to be met, and the level of confidence (evaluation assurance level)
to which it is asserted that the TOE satisfies its IT security requirements. This
document forms the baseline for the Common Criteria (CC) evaluation.
1.1 DOCUMENT ORGANIZATION
Section 1, ST Introduction, provides the Security Target reference, the Target
of Evaluation reference, the TOE overview and the TOE description.
Section 2, Conformance Claims, describes how the ST conforms to the
Common Criteria, Protection Profile (PP) and PP Modules.
Section 3, Security Problem Definition, describes the expected environment
in which the TOE is to be used. This section defines the set of threats that are
relevant to the secure operation of the TOE, organizational security policies with
which the TOE must comply, and secure usage assumptions applicable to this
analysis.
Section 4, Security Objectives, defines the set of security objectives to be
satisfied by the TOE and by the TOE operating environment in response to the
problem defined by the security problem definition.
Section 5, Extended Components Definition, defines the extended
components which are then detailed in Section 6.
Section 6, Security Functional Requirements, specifies the security
functional requirements that must be satisfied by the TOE and the IT
environment.
Section 7, Security Assurance Requirements, specifies the security
assurance requirements that must be satisfied by the TOE and the IT
environment.
Section 8, Security Requirements Rationale, provides a rationale for the
selection of functional and assurance requirements.
Section 9, TOE Summary Specification, describes the security functions that
are included in the TOE to enable it to meet the IT security functional
requirements.
Section 10, Terminology and Acronyms, defines the acronyms and
terminology used in this ST.
Section 11, References, provides a list of documents referenced in this ST.
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1.2 SECURITY TARGET REFERENCE
ST Title: High Sec Labs SK21PH-4, SK41PH-4, DK22PH-4,
DK42PH-4, SK81PH-4, DK82PH-4, SX42PH-4, SX82PH-
4 Firmware Version 44404-E7E7 Peripheral Sharing
Devices Security Target
ST Version: 1.0
ST Date: 20 November 2023
1.3 TOE REFERENCE
TOE Identification: High Sec Labs SK21PH-4, SK41PH-4, DK22PH-4,
DK42PH-4, SK81PH-4, DK82PH-4, SX42PH-4, SX82PH-
4 Firmware Version 44404-E7E7 Peripheral Sharing
Devices
TOE Developer: High Sec Labs Ltd.
TOE Type: Peripheral Sharing Device (Other Devices and Systems)
1.4 TOE OVERVIEW
The High Sec Labs (HSL) Secure Keyboard, Video, Mouse (KVM) Switches allow
users to share keyboard, video, and mouse peripherals between a number of
connected computers. These devices also allow for the sharing of audio
peripherals. Security features ensure isolation between computers and
peripherals to prevent data leakage between connected systems.
The HSL Matrix Switches allow users to view and control two computers while
securely sharing keyboard, video, mouse, and audio peripherals between a
number of connected computers.
The following security features are provided by the HSL Peripheral Sharing
Devices:
• Video Security
• Computer video input interfaces are isolated through the use of
separate electronic components, power and ground domains
• The display is isolated by dedicated, read-only, Extended Display
Identification Data (EDID) emulation for each computer
• Access to the monitor’s EDID is blocked
• Access to the Monitor Control Command Set (MCCS commands) is
blocked
• Both DisplayPort (DP) and High-Definition Multimedia Interface
(HDMI) video peripherals are supported
• Video input is accepted as DisplayPort or HDMI
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• Keyboard and Mouse Security
• The keyboard and mouse are isolated by dedicated, USB device
emulation for each computer
• One-way, peripheral-to-computer data flow is enforced through
unidirectional optical data diodes
• Communication from computer-to-keyboard/mouse is blocked
• Non HID (Human Interface Device) data transactions are blocked
• Audio Security
• One-way computer to speaker sound flow is enforced through
unidirectional optical data diodes
• Hardware Anti-Tampering
• Any attempt to open the product enclosure will activate an anti-
tampering system, making the product inoperable and indicating
tampering via blinking Light Emitting Diodes (LEDs)
• Special holographic tampering evident labels on the product’s
enclosure provide a clear visual indication if the product has been
opened or compromised
High Sec Labs secure peripheral sharing devices use multiple isolated
microcontrollers (one microcontroller per connected computer) to emulate
connected peripherals in order to prevent an unauthorized data flow through bit-
by-bit signaling.
The TOE is a combined software and hardware TOE. A mapping showing the
applicable SFRs for each device is included in Table 11.
TOE Environment
The following components are required for operation of the TOE in the evaluated
configuration.
Component Description
Connected Computers 2-8 General purpose computers
Keyboard General purpose USB keyboard
Mouse General purpose USB mouse
Audio output device Analog audio output device (speakers or headphones)
User display Standard computer display (HDMI 2.0 or DisplayPort 1.1,
1.2 or 1.3)
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Component Description
HSL KVM Cables USB Type-A to USB Type-B (keyboard and mouse)
Video cable (DisplayPort, HDMI)
3.5mm stereo cable (Audio cable)
Table 1 – Non-TOE Hardware and Software
1.5 TOE DESCRIPTION
Evaluated Configuration
Figure 1 – Evaluated Configuration
Figure 1 shows a basic evaluated configuration. In the evaluated configuration,
the TOE is connected to two, four or eight computers. The video input is
DisplayPort or HDMI, and one or two displays are connected. The peripheral
sharing device is connected to keyboard, mouse and speakers or headphones.
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Physical Scope
The TOE consists of the devices shown in Table 2.
Family Family Description
Part
Number
Model
Number
of
Computer
Ports
Active
Anti-
tampering
Tamper
Evident
labels
Analog
Audio
Video in
Video
out
Number
of
supported
displays
Keyboard and Mouse
KVM KVM devices
CGA19475 SK21PH-4 2 Yes Yes Yes DP/HDMI DP/HDMI 1 Yes
CGA19253 SK41PH-4 4 Yes Yes Yes DP/HDMI DP/HDMI 1 Yes
CGA19255 DK22PH-4 2 Yes Yes Yes DP/HDMI DP/HDMI 2 Yes
CGA19476 DK42PH-4 4 Yes Yes Yes DP/HDMI DP/HDMI 2 Yes
CGA19262 SK81PH-4 8 Yes Yes Yes DP/HDMI DP/HDMI 1 Yes
CGA19472 DK82PH-4 8 Yes Yes Yes DP/HDMI DP/HDMI 2 Yes
KVM
Matrix
Secure KVM Matrix devices
CGA19453 SX42PH-4 4 Yes Yes Yes DP/HDMI DP/HDMI 2 Yes
CGA19458 SX82PH-4 8 Yes Yes Yes DP/HDMI DP/HDMI 2 Yes
Table 2 – TOE Peripheral Sharing Devices and Features
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1.5.2.1 TOE Delivery
The TOE, together with its corresponding cables are delivered to the customer
via trusted carrier, such as Fed-Ex, that provide a tracking service for all
shipments.
1.5.2.2 TOE Guidance
The TOE includes the following guidance documentation:
• HSL Quick Installation Guide 2/4/8 Ports High Security DP/HDMI KVM
Switches, HDC31273 Rev 1.0
• HSL Quick Installation Guide 4/8 Ports High Security DP/HDMI Mini-Matrix
KVM Switches, HDC31272 Rev 1.0
Guidance may be downloaded from the High Sec Labs website
(https://highseclabs.com/quick-start-guides/) in .pdf format.
The following guidance is available upon request by emailing
support@highseclabs.com:
• High Sec Labs SK21PH-4, SK41PH-4, DK22PH-4, DK42PH-4, SK81PH-4,
DK82PH-4, SX42PH-4, SX82PH-4 Firmware Version 44404-E7E7
Peripheral Sharing Devices Common Criteria Guidance Supplement,
Version 1.3
Logical Scope
The logical boundary of the TOE includes all interfaces and functions within the
physical boundary. The logical boundary of the TOE may be broken down by the
security function classes described in Section 6. Table 3 summarizes the logical
scope of the TOE.
Functional Classes Description
User Data Protection The TOE provides secure switching capabilities for keyboard
and mouse, display, and audio output. The TOE ensures
that only authorized peripheral devices may be used and
prevents re-enumeration for devices. The TOE ensures that
audio signals are filtered before transmission according to
protocols.
Protection of the TSF1
The TOE ensures a secure state in the case of failure,
provides only restricted access, and performs self-testing.
The TOE provides both passive detection of physical attack,
and active resistance to attack.
1
TOE Security Functionality
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Functional Classes Description
TOE Access The TOE provides a continuous indication of which
computer is currently selected.
Table 3 – Logical Scope of the TOE
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2 CONFORMANCE CLAIMS
2.1 COMMON CRITERIA CONFORMANCE CLAIM
This Security Target claims to be conformant to Version 3.1 of Common Criteria
for Information Technology Security Evaluation according to:
• Common Criteria for Information Technology Security Evaluation, Part 1:
Introduction and General Model; CCMB-2017-04-001, Version 3.1,
Revision 5, April 2017
• Common Criteria for Information Technology Security Evaluation, Part 2:
Security Functional Components; CCMB-2017-04-002, Version 3.1,
Revision 5, April 2017
• Common Criteria for Information Technology Security Evaluation, Part 3:
Security Assurance Components CCMB-2017-04-003, Version 3.1,
Revision 5, April 2017
As follows:
• CC Part 2 extended
• CC Part 3 conformant
The Common Methodology for Information Technology Security Evaluation,
Version 3.1, Revision 5, April 2017 has been taken into account.
2.2 PP-CONFIGURATION CONFORMANCE CLAIM
This ST claims exact conformance with the National Information Assurance
Partnership (NIAP) PP‐Configuration for Peripheral Sharing Device, Analog Audio
Output Devices, Keyboard/Mouse Devices, and Video/Display Devices, 19 July
2019 [CFG_PSD‐AO‐KM‐VI_V1.0].
This PP-Configuration includes the following components:
• Base-PP: Protection Profile for Peripheral Sharing Device, Version 4.0
[PP_PSD_V4.0]
• PP-Module: PP-Module for Keyboard/Mouse Devices, Version 1.0
[MOD_KM_V1.0]
• PP-Module: PP-Module for Video/Display Devices, Version 1.0
[MOD_VI_V1.0]
• PP-Module: PP-Module for Analog Audio Output Devices, Version 1.0
[MOD_AO_V1.0]
2.3 TECHNICAL DECISIONS
The Technical Decisions in Table 4 apply to the PP and the modules and have
been accounted for in the ST and in the evaluation.
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TD Name PP affected Relevant
Y/N
TD0506 Missing Steps to disconnect and
reconnect display
[MOD_VI_V1.0] Y
TD0507 Clarification on USB plug type [MOD_KM_V1.0] Y
TD0514 Correction to MOD VI FDP_APC_EXT.1
Test 3 Step 6
[MOD_VI_V1.0] Y
TD0518 Typographical errors in dependency
Table
[PP_PSD_V4.0] Y
TD0539 Incorrect selection trigger in
FTA_CIN_EXT.1 in MOD_VI_V1.0
[MOD_VI_V1.0] Y
TD0557 Correction to Audio Filtration
Specification table in FDP_AFL_EXT.1
[MOD_AO_V1.0] Y
TD0583 FPT_PHP.3 modified for remote
controllers
[PP_PSD_V4.0] Y
TD0584 Update to FDP_APC_EXT.1 Video Tests [MOD_VI_V.10] Y
TD0585 Update to FDPAPC_EXT.1 Audio Output
Tests
[MOD_AO_V1.0] Y
TD0586 DisplayPort and HDMI Interfaces in
FDP_IPC_EXT.1
[MOD_VI_V.10] Y
TD0593 Equivalency Arguments for PSD [MOD_AO_V1.0],
[MOD_KM_V1.0],
[MOD_VI_V1.0]
Y
TD0620 EDID Read Requirements [MOD_VI_V1.0] Y
TD0681 PSD purging of EDID data upon
disconnect
[MOD_VI_V1.0] Y
TD0686 DisplayPort CEC Testing [MOD_VI_V1.0] Y
Table 4 – Applicable Technical Decisions
2.4 PACKAGE CLAIM
This Security Target does not claim conformance with any package.
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2.5 CONFORMANCE RATIONALE
The TOE Keyboard, Video, Mouse (KVM) and Matrix devices are inherently
consistent with the Compliant Targets of Evaluation described in the
[PP_PSD_V4.0] and in the PP modules listed in Section 2.2, and with the PP‐
Configuration for Peripheral Sharing Device, Analog Audio Output Devices,
Keyboard/Mouse Devices, and Video/Display Devices [CFG_PSD‐AO‐KM‐
VI_V1.0].
The security problem definition, statement of security objectives and statement
of security requirements in this ST conform exactly to the security problem
definition, statement of security objectives and statement of security
requirements contained in [PP_PSD_V4.0] and the modules listed in Section 2.2.
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3 SECURITY PROBLEM DEFINITION
3.1 THREATS
Table 5 lists the threats described in Section 3.1 of the [PP_PSD_V4.0].
Mitigation to the threats is through the objectives identified in Section 4.1,
Security Objectives for the TOE.
Threat Description
T.DATA_LEAK A connection via the PSD2
between one or more
computers may allow unauthorized data flow through
the PSD or its connected peripherals.
T.SIGNAL_LEAK A connection via the PSD between one or more
computers may allow unauthorized data flow through
bit‐by‐bit signaling.
T.RESIDUAL_LEAK A PSD may leak (partial, residual, or echo) user data
between the intended connected computer and another
unintended connected computer.
T.UNINTENDED_USE A PSD may connect the user to a computer other than
the one to which the user intended to connect.
T.UNAUTHORIZED_DEVICES The use of an unauthorized peripheral device with a
specific PSD peripheral port may allow unauthorized
data flows between connected devices or enable an
attack on the PSD or its connected computers.
T.LOGICAL_TAMPER An attached device (computer or peripheral) with
malware, or otherwise under the control of a
malicious user, could modify or overwrite code or
data stored in the PSD’s volatile or non‐volatile
memory to allow unauthorized information flows.
T.PHYSICAL_TAMPER A malicious user or human agent could physically
modify the PSD to allow unauthorized information
flows.
T.REPLACEMENT A malicious human agent could replace the PSD
during shipping, storage, or use with an alternate
device that does not enforce the PSD security
policies.
2
Peripheral Sharing Device
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Threat Description
T.FAILED Detectable failure of a PSD may cause an
unauthorized information flow or weakening of PSD
security functions.
T.MICROPHONE_USE A malicious agent could use an unauthorized
peripheral device such as a microphone, connected to
the TOE audio out peripheral device interface to
eavesdrop or transfer data across an air‐gap through
audio signaling.
T.AUDIO_REVERSED A malicious agent could repurpose an authorized
audio output peripheral device by converting it to a
low‐gain microphone to eavesdrop on the
surrounding audio or transfer data across an air‐gap
through audio signaling.
Table 5 – Threats
3.2 ORGANIZATIONAL SECURITY POLICIES
There are no Organizational Security Policies applicable to this TOE.
3.3 ASSUMPTIONS
The assumptions required to ensure the security of the TOE are listed in Table 6.
Assumptions Description
A.NO_TEMPEST Computers and peripheral devices connected to the
PSD are not TEMPEST approved.
The TSF may or may not isolate the ground of the
keyboard and mouse computer interfaces (the USB
ground). The Operational Environment is assumed not
to support TEMPEST red‐black ground isolation.
A.PHYSICAL The environment provides physical security
commensurate with the value of the TOE and the data
it processes and contains.
A.NO_WIRELESS_DEVICES The environment includes no wireless peripheral
devices.
A.TRUSTED_ADMIN PSD Administrators and users are trusted to follow and
apply all guidance in a trusted manner.
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Assumptions Description
A.TRUSTED_CONFIG Personnel configuring the PSD and its operational
environment follow the applicable security
configuration guidance.
A.USER_ALLOWED_ACCESS All PSD users are allowed to interact with all
connected computers. It is not the role of the PSD to
prevent or otherwise control user access to connected
computers. Computers or their connected network
shall have the required means to authenticate the user
and to control access to their various resources.
A.NO_SPECIAL_ANALOG
_CAPABILITIES
The computers connected to the TOE are not equipped
with special analog data collection cards or peripherals
such as analog to digital interface, high performance
audio interface, digital signal processing function, or
analog video capture function.
A.NO_MICROPHONES Users are trained not to connect a microphone to the
TOE audio output interface.
Table 6 – Assumptions
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4 SECURITY OBJECTIVES
The purpose of the security objectives is to address the security concerns and to
show which security concerns are addressed by the TOE, and which are
addressed by the environment. Threats may be addressed by the TOE or the
security environment or both. Therefore, the CC identifies two categories of
security objectives:
• Security objectives for the TOE
• Security objectives for the environment
4.1 SECURITY OBJECTIVES FOR THE TOE
This section identifies and describes the security objectives that are to be
addressed by the TOE, and traces each Security Functional Requirement (SFR)
back to a security objective of the TOE.
Security Objective Description
O.COMPUTER
_INTERFACE
_ISOLATION
The PSD shall prevent unauthorized data flow to ensure that
the PSD and its connected peripheral devices cannot be
exploited in an attempt to leak data. The TOE‐Computer
interface shall be isolated from all other PSD‐Computer
interfaces while TOE is powered.
Addressed by:
MOD_AO FDP_APC_EXT.1/AO, FDP_PDC_EXT.1,
FDP_PDC_EXT.2/AO, FDP_PUD_EXT.1
MOD_VI FDP_APC_EXT.1/VI, FDP_PDC_EXT.1
MOD_KM FDP_APC_EXT.1/KM, FDP_FIL_EXT.1/KM,
FDP_PDC_EXT.1, FDP_RDR_EXT.1,
FDP_SWI_EXT.3
O.COMPUTER
_INTERFACE
_ISOLATION
_TOE_UNPOWERED
The PSD shall not allow data to transit a PSD‐Computer
interface while the PSD is unpowered.
Addressed by:
MOD_AO FDP_APC_EXT.1/AO, FDP_PDC_EXT.1,
FDP_PDC_EXT.2/AO, FDP_PUD_EXT.1
MOD_VI FDP_APC_EXT.1/VI, FDP_PDC_EXT.1
MOD_KM FDP_APC_EXT.1/KM, FDP_FIL_EXT.1/KM,
FDP_PDC_EXT.1, FDP_RDR_EXT.1,
FDP_SWI_EXT.3
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Security Objective Description
O.USER_DATA
_ISOLATION
The PSD shall route user data, such as keyboard entries, only
to the computer selected by the user. The PSD shall provide
isolation between the data flowing from the peripheral device
to the selected computer and any non‐selected computer.
Addressed by:
MOD_AO FDP_APC_EXT.1/AO, FDP_PDC_EXT.1,
FDP_PDC_EXT.2/AO, FDP_PUD_EXT.1
MOD_VI FDP_APC_EXT.1/VI, FDP_PDC_EXT.1
MOD_KM FDP_APC_EXT.1/KM, FDP_FIL_EXT.1/KM,
FDP_PDC_EXT.1, FDP_RDR_EXT.1,
FDP_SWI_EXT.3
O.NO_USER
_DATA_RETENTION
The PSD shall not retain user data in non‐volatile memory
after power up or, if supported, factory reset.
Addressed by:
PP_PSD FDP_RIP_EXT.1
MOD_KM FDP_RIP.1/KM
O.NO_OTHER
_EXTERNAL
_INTERFACES
The PSD shall not have any external interfaces other than
those implemented by the TSF.
Addressed by:
PP_PSD FDP_PDC_EXT.1
O.LEAK
_PREVENTION
_SWITCHING
The PSD shall ensure that there are no switching mechanisms
that allow signal data leakage between connected computers.
Addressed by:
PP_PSD FDP_SWI_EXT.1, FDP_SWI_EXT.2(1),
FDP_SWI_EXT.2(2)
O.AUTHORIZED
_USAGE
The TOE shall explicitly prohibit or ignore unauthorized
switching mechanisms, either because it supports only one
connected computer or because it allows only authorized
mechanisms to switch between connected computers.
Authorized switching mechanisms shall require express user
action restricted to console buttons, console switches, console
touch screen, wired remote control, and peripheral devices
using a guard. Unauthorized switching mechanisms include
keyboard shortcuts, also known as “hotkeys,” automatic port
scanning, control through a connected computer, and control
through keyboard shortcuts. Where applicable, the results of
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Security Objective Description
the switching activity shall be indicated by the TSF so that it
is clear to the user that the switching mechanism was
engaged as intended.
A conformant TOE may also provide a management function
to configure some aspects of the TSF. If the TOE provides this
functionality, it shall ensure that whatever management
functions it provides can only be performed by authorized
administrators and that an audit trail of management
activities is generated.
Addressed by:
PP_PSD FDP_SWI_EXT.1, FDP_SWI_EXT.2(1),
FDP_SWI_EXT.2(2), FTA_CIN_EXT.1
MOD_VI FDP_CDS_EXT.1(1), FDP_CDS_EXT.1(2),
FTA_CIN_EXT.1
MOD_KM FDP_FIL_EXT.1/KM
O.PERIPHERAL
_PORTS_ISOLATION
The PSD shall ensure that data does not flow between
peripheral devices connected to different PSD interfaces.
Addressed by:
MOD_AO FDP_APC_EXT.1/AO, FDP_PDC_EXT.1,
FDP_PDC_EXT.2/AO, FDP_PUD_EXT.1
MOD_VI FDP_APC_EXT.1/VI, FDP_PDC_EXT.1
MOD_KM FDP_APC_EXT.1/KM, FDP_FIL_EXT.1/KM,
FDP_PDC_EXT.1, FDP_RDR_EXT.1,
FDP_SWI_EXT.3
O.REJECT
_UNAUTHORIZED
_PERIPHERAL
The PSD shall reject unauthorized peripheral device types and
protocols.
Addressed by:
PP_PSD FDP_PDC_EXT.1
MOD_AO FDP_APC_EXT.1/AO, FDP_PDC_EXT.1,
FDP_PDC_EXT.2/AO, FDP_PUD_EXT.1
MOD_VI FDP_PDC_EXT.2/VI, FDP_PDC_EXT.3/VI,
FDP_IPC_EXT.1, FDP_SPR_EXT.1/DP,
FDP_SPR_EXT.1/HDMI
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Security Objective Description
MOD_KM FDP_APC_EXT.1/KM, FDP_FIL_EXT.1/KM,
FDP_PDC_EXT.1, FDP_RDR_EXT.1,
FDP_SWI_EXT.3, FDP_PDC_EXT.2/KM,
FDP_PDC_EXT.3/KM
O.REJECT
_UNAUTHORIZED
_ENDPOINTS
The PSD shall reject unauthorized peripheral devices
connected via a Universal Serial Bus (USB) hub.
Addressed by:
PP_PSD FDP_PDC_EXT.1
MOD_KM FDP_APC_EXT.1/KM, FDP_FIL_EXT.1/KM,
FDP_PDC_EXT.1, FDP_RDR_EXT.1,
FDP_SWI_EXT.3
O.NO_TOE_ACCESS The PSD firmware, software, and memory shall not be
accessible via its external ports.
Addressed by:
PP_PSD FPT_NTA_EXT.1
O.TAMPER
_EVIDENT
_LABEL
The PSD shall be identifiable as authentic by the user and the
user must be made aware of any procedures or other such
information to accomplish authentication. This feature must
be available upon receipt of the PSD and continue to be
available during the PSD deployment. The PSD shall be
labeled with at least one visible unique identifying tamper‐
evident marking that can be used to authenticate the device.
The PSD manufacturer must maintain a complete list of
manufactured PSD articles and their respective identification
markings’ unique identifiers.
Addressed by:
PP_PSD FPT_PHP.1
O.ANTI_TAMPERING The PSD shall be physically enclosed so that any attempts to
open or otherwise access the internals or modify the
connections of the PSD would be evident, and optionally
thwarted through disablement of the TOE. Note: This applies
to a wired remote control as well as the main chassis of the
PSD.
Addressed by:
PP_PSD FPT_PHP.1, FPT_PHP.3
O.SELF_TEST The PSD shall perform self‐tests following power up or
powered reset.
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Security Objective Description
Addressed by:
PP_PSD FPT_TST.1
O.SELF_TEST
_FAIL_TOE
_DISABLE
The PSD shall enter a secure state upon detection of a critical
failure.
Addressed by:
PP_PSD FPT_FLS_EXT.1, FPT_TST_EXT.1
O.SELF_TEST
_FAIL_INDICATION
The PSD shall provide clear and visible user indications in the
case of a self‐test failure.
Addressed by:
PP_PSD FPT_TST_EXT.1
O.PROTECTED
_EDID
The TOE shall read the connected display Extended Display
Identification Data (EDID) once during the TOE power up or
reboot sequence and prevent any EDID channel write
transactions that connected computers initiate.
Addressed by:
MOD_VI FDP_PDC_EXT.2/VI, FDP_SPR_EXT.1/DP,
FDP_SPR_EXT.1/HDMI
O.UNIDIRECTIONAL
_VIDEO
The TOE shall enforce unidirectional video data flow from the
connected computer video interface to the display interface
only.
Addressed by:
MOD_VI FDP_UDF_EXT.1/VI
O.UNIDIRECTIONAL
_AUDIO_OUT
The PSD shall enforce the unidirectional flow of audio data
from the analog audio computer interface to the analog audio
peripheral interface.
Addressed by:
MOD_AO FDP_APC_EXT.1/AO, FDP_AFL_EXT.1,
FDP_UDF_EXT.1/AO
O.COMPUTER_TO
_AUDIO_ISOLATION
The PSD shall isolate the analog audio output function from
all other TOE functions.
Addressed by:
MOD_AO FDP_APC_EXT.1/AO, FDP_UDF_EXT.1/AO
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Security Objective Description
O.EMULATED_INPUT The TOE shall emulate the keyboard and/or mouse functions
from the TOE to the connected computer.
Addressed by:
MOD_KM FDP_PDC_EXT.2/KM, FDP_PDC_EXT.3/KM
O.UNIDIRECTIONAL
_INPUT
The TOE shall enforce unidirectional keyboard and/or mouse
device’s data flow from the peripheral device to only the
selected computer.
Addressed by:
MOD_KM FDP_UDF_EXT.1/KM
Table 7 – Security Objectives for the TOE
4.2 SECURITY OBJECTIVES FOR THE
OPERATIONAL ENVIRONMENT
This section identifies and describes the security objectives that are to be
addressed by the IT environment or by non-technical or procedural means.
Security Objective Description
OE.NO_TEMPEST The operational environment will not use TEMPEST
approved equipment.
OE.PHYSICAL The operational environment will provide physical
security, commensurate with the value of the PSD
and the data that transits it.
OE.NO_WIRELESS_DEVICES The operational environment will not include
wireless keyboards, mice, audio, user
authentication, or video devices.
OE.TRUSTED_ADMIN The operational environment will ensure that trusted
PSD Administrators and users are appropriately
trained.
OE.TRUSTED_CONFIG The operational environment will ensure that
administrators configuring the PSD and its
operational environment follow the applicable
security configuration guidance.
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OE.NO_SPECIAL_ANALOG
_CAPABILITIES
The operational environment will not have special
analog data collection cards or peripherals such as
analog to digital interface, high performance audio
interface, or a component with digital signal
processing or analog video capture functions.
OE.NO_MICROPHONES The operational environment is expected to ensure
that microphones are not plugged into the TOE
audio output interfaces.
Table 8 – Security Objectives for the Operational Environment
4.3 SECURITY OBJECTIVES RATIONALE
The security objectives rationale describes how the assumptions and threats
map to the security objectives.
Threat or
Assumption
Security
Objective(s)
Rationale
T.DATA_LEAK O.COMPUTER
_INTERFACE
_ISOLATION
Isolation of computer interfaces
prevents data from leaking between
them without authorization.
O.COMPUTER
_INTERFACE
_ISOLATION
_TOE_UNPOWERED
Maintaining interface isolation while
the TOE is in an unpowered state
ensures that data cannot leak
between computer interfaces.
O.USER_DATA
_ISOLATION
The TOE’s routing of data only to the
selected computer ensures that it will
not leak to any others.
O.NO_OTHER
_EXTERNAL
_INTERFACES
The absence of additional external
interfaces ensures that there is no
unexpected method by which data
can be leaked.
O.PERIPHERAL_PORTS
_ISOLATION
Isolation of peripheral ports prevents
data from leaking between them
without authorization.
O.UNIDIRECTIONAL
_INPUT
The TOE’s enforcement of
unidirectional input for
keyboard/mouse data prevents
leakage of computer data through a
connected peripheral interface.
O.PROTECTED_EDID The TOE’s protection of the EDID
interface prevents its use as a vector
for unauthorized data leakage via this
channel.
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Threat or
Assumption
Security
Objective(s)
Rationale
O.UNIDIRECTIONAL
_VIDEO
The TOE’s enforcement of
unidirectional output for video data
protects against data leakage via
connected computers by ensuring
that no video data can be input to a
connected computer through this
interface.
T.SIGNAL_LEAK O.COMPUTER
_INTERFACE
_ISOLATION
Isolation of computer interfaces
prevents data leakage through bit‐
wise signaling because there is no
mechanism by which the signal data
can be communicated.
O.NO_OTHER
_EXTERNAL
_INTERFACES
The absence of additional external
interfaces ensures that there is no
unexpected method by which data
can be leaked through bitwise
signaling.
O.LEAK_PREVENTION
_SWITCHING
The TOE’s use of switching methods
that are not susceptible to signal
leakage helps mitigate the signal leak
threat.
O.UNIDIRECTIONAL
_INPUT
The TOE’s enforcement of
unidirectional input for
keyboard/mouse data prevents
leakage of computer data through bit‐
by‐bit signaling to a connected
peripheral interface.
O.PROTECTED_EDID The TOE’s protection of the EDID
interface prevents its use as a vector
for bit‐by‐bit signal leakage via this
channel.
O.UNIDIRECTIONAL
_VIDEO
The TOE’s enforcement of
unidirectional output for video data
protects against signaling leakage via
connected computers by ensuring
that no video data can be input to a
connected computer through this
interface.
O.UNIDIRECTIONAL
_AUDIO_OUT
O.UNIDIRECTIONAL_AUDIO_OUT
mitigates this threat by preventing
the exploitation of the analog audio
output to receive signaled data from
a connected computer. Analog audio
output in standard computers may be
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Threat or
Assumption
Security
Objective(s)
Rationale
exploited to become audio input in
some audio codecs. Audio devices
such as headphones may also be
used as low‐gain dynamic
microphones. If the TOE design
assures that analog audio reverse
signal attenuation is below the noise
floor level then the audio signal may
not be recovered from the resultant
audio stream. This prevents potential
misuse of headphones connected to
the TOE for audio eavesdropping.
O.COMPUTER_TO
_AUDIO_ISOLATION
O.COMPUTER_TO_AUDIO_ISOLATION
mitigates this threat by ensuring that
analog audio output converted to
input by a malicious driver cannot
pick up signals from other computer
interfaces. A TOE design that ensures
that audio signals are not leaked to
any other TOE interface can
effectively prevent a potential
signaling leakage across the TOE
through analog audio.
T.RESIDUAL
_LEAK
O.NO_USER_DATA
_RETENTION
The TOE’s lack of data retention
ensures that a residual data leak is
not possible.
O.PROTECTED_EDID The TOE’s protection of the EDID
interface prevents the leakage of
residual data by ensuring that no
such data can be written to EDID
memory.
T.UNINTENDED
_USE
O.AUTHORIZED
_USAGE
The TOE’s support for only switching
mechanisms that require explicit user
action to engage ensures that a user
has sufficient information to avoid
interacting with an unintended
computer.
T.UNAUTHORIZED
_DEVICES
O.REJECT
_UNAUTHORIZED
_ENDPOINTS
The TOE’s ability to reject
unauthorized endpoints mitigates the
threat of unauthorized devices being
used to communicate with connected
computers.
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Threat or
Assumption
Security
Objective(s)
Rationale
O.REJECT
_UNAUTHORIZED
_PERIPHERAL
The TOE’s ability to reject
unauthorized peripherals mitigates
the threat of unauthorized devices
being used to communicate with
connected computers.
O.EMULATED_INPUT The TOE’s emulation of
keyboard/mouse data input ensures
that a connected computer will only
receive this specific type of data
through a connected peripheral.
O.UNIDIRECTIONAL
_VIDEO
The TOE’s limitation of supported
video protocol interfaces prevents the
connection of unauthorized devices.
T.LOGICAL
_TAMPER
O.NO_TOE_ACCESS The TOE’s prevention of logical
access to its firmware, software, and
memory mitigates the threat of
logical tampering.
O.EMULATED_INPUT The TOE’s emulation of
keyboard/mouse data input prevents
logical tampering of the TSF ensuring
that only known inputs to it are
supported.
T.PHYSICAL
_TAMPER
O.ANTI_TAMPERING The TOE mitigates the threat of
physical tampering through use of an
enclosure that provides tamper
detection functionality.
O.TAMPER_EVIDENT
_LABEL
The TOE mitigates the threat of
physical tampering through use of
tamper evident labels that reveal
physical tampering attempts.
T.REPLACEMENT O.TAMPER_EVIDENT
_LABEL
The TOE’s use of a tamper evident
label that provides authenticity of the
device mitigates the threat that it is
substituted for a replacement device
during the acquisition process.
T.FAILED O.SELF_TEST The TOE mitigates the threat of
failures leading to compromise of
security functions through self‐tests
of its own functionality.
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Threat or
Assumption
Security
Objective(s)
Rationale
O.SELF_TEST_FAIL
_TOE_DISABLE
The TOE mitigates the threat of
failures leading to compromise of
security functions by disabling all
data flows in the event a failure is
detected.
O.SELF_TEST_FAIL
_INDICATION
The TOE mitigates the threat of
failures leading to compromise of
security functions by providing users
with a clear indication when it is in a
failure state and should not be
trusted.
T.MICROPHONE_USE O.UNIDIRECTIONAL
_AUDIO_OUT
O.UNIDIRECTIONAL_AUDIO_OUT
mitigates this threat by attenuating
the strength of any inbound
transmission of audio data through
the TOE from a connected peripheral.
If the TOE design ensures that analog
audio reverse signal attenuation is
below the noise floor level then any
audio signal should not have
sufficient strength to be usable.
T.AUDIO_REVERSED O.UNIDIRECTIONAL
_AUDIO_OUT
O.UNIDIRECTIONAL_AUDIO_OUT
mitigates this threat by ensuring that
the TOE’s audio peripheral
interface(s) are exclusively used to
output audio.
A.NO_TEMPEST OE.NO_TEMPEST If the TOE’s operational environment
does not include TEMPEST approved
equipment, then the assumption is
satisfied.
A.NO_PHYSICAL OE.PHYSICAL If the TOE’s operational environment
provides physical security, then the
assumption is satisfied.
A.NO_WIRELESS
_DEVICES
OE.NO_WIRELESS
_DEVICES
If the TOE’s operational environment
does not include wireless peripherals,
then the assumption is satisfied.
A.TRUSTED_ADMIN OE.TRUSTED
_ADMIN
If the TOE’s operational environment
ensures that only trusted
administrators will manage the TSF,
then the assumption is satisfied.
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Threat or
Assumption
Security
Objective(s)
Rationale
A.TRUSTED
_CONFIG
OE.TRUSTED
_CONFIG
If TOE administrators follow the
provided security configuration
guidance, then the assumption is
satisfied.
A.USER_ALLOWED
_ACCESS
OE.PHYSICAL If the TOE’s operational environment
provides physical access to connected
computers, then the assumption is
satisfied.
A.NO_SPECIAL
_ANALOG
_CAPABILITIES
OE.NO_SPECIAL
_ANALOG
_CAPABILITIES
If administrators in the TOE’s
operational environment take care to
ensure that computers with special
analog data collection interfaces are
not connected to the TOE, then the
assumption that such components
are not present is satisfied.
A.NO
_MICROPHONES
OE.NO
_MICROPHONES
The assumption is upheld by the
objective since the users in the
environment are trained not to
connect a microphone to the TOE
audio output interface,
Table 9 – Security Objectives Rationale
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5 EXTENDED COMPONENTS DEFINITION
The extended components definition is presented in Appendix C of the Protection
Profile for Peripheral Sharing Device [PP_PSD_V4.0] and in the modules for
analog audio output devices [MOD_AO_V1.0], keyboard/mouse devices
[MOD_KM_V1.0], and display devices [MOD_VI_1.0].
The families to which these components belong are identified in the following
table:
Functional
Class
Functional Families Protection Profile
Modules
User Data Protection
(FDP)
FDP_AFL_EXT Audio Filtration [MOD_AO_V1.0]
FDP_APC_EXT Active PSD Connections [MOD_AO_V1.0],
[MOD_KM_V1.0],
[MOD_VI_V1.0]
FDP_CDS_EXT Connected Displays Supported [MOD_VI_V1.0]
FDP_FIL_EXT Device Filtering [MOD_KM_V1.0]
FDP_IPC_EXT Internal Protocol Conversion [MOD_VI_V1.0]
FDP_PDC_EXT Peripheral Device Connection [PP_PSD_V4.0],
[MOD_AO_V1.0],
[MOD_KM_V1.0],
[MOD_VI_V1.0]
FDP_PUD_EXT Powering Unauthorized Devices [MOD_AO_V1.0]
FDP_RDR_EXT Re-Enumeration Device Rejection [MOD_KM_V1.0]
FDP_RIP_EXT Residual Information Protection [PP_PSD_V4.0]
FDP_SPR_EXT Sub-Protocol Rules [MOD_VI_V1.0]
FDP_SWI_EXT PSD Switching [PP_PSD_V4.0],
[MOD_KM_V1.0]
FDP_UDF_EXT Unidirectional Data Flow [MOD_AO_V1.0],
[MOD_KM_V1.0],
[MOD_VI_V1.0]
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Functional
Class
Functional Families Protection Profile
Modules
Protection of the TSF
(FPT)
FPT_FLS_EXT Failure with Preservation of
Secure State
[PP_PSD_V4.0]
FPT_NTA_EXT No Access to TOE [PP_PSD_V4.0]
FPT_TST_EXT TSF Testing [PP_PSD_V4.0]
TOE Access (FTA) FTA_CIN_EXT Continuous Indications [PP_PSD_V4.0]
Table 10 – Functional Families of Extended Components
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6 SECURITY FUNCTIONAL
REQUIREMENTS
Section 6 provides security functional and assurance requirements that must be
satisfied by a compliant TOE.
6.1 CONVENTIONS
The CC permits four types of operations to be performed on functional
requirements: selection, assignment, refinement, and iteration. This is defined
as:
• Assignment: Indicated by surrounding brackets and underline, e.g.,
[assigned item].
• Selection: Indicated by surrounding brackets and italics, e.g., [selected
item].
• Refinement: Refined components are identified by using [bold
surrounded by brackets] for additional information, or [strikeout
surrounded by brackets] for deleted text.
• Iteration: Iteration operations for iterations within the Protection Profile
and associated modules are identified with a slash (‘/’) and an identifier
(e.g. “/KM”). Where multiple iterations of the SFR are required within the
ST, a number is appended to the SFR identifier (e.g.
“FDP_CDS_EXT.1(1)”).
Extended SFRs are identified by the inclusion of “EXT” in the SFR name.
The CC operations already performed in the PP and PP modules are reproduced
in plain text and not denoted in this ST. The requirements have been copied
from the PP and PP modules and any remaining operations have been completed
herein. Refer to the PP and PP modules to identify those operations.
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6.2 SECURITY FUNCTIONAL REQUIREMENTS
Table 11 details the security functional requirements.
Class Identifier Name Source Applicable
Devices
User Data
Protection
(FDP)
FDP_AFL_EXT.1 Audio Filtration [MOD_AO_V1.0] All
FDP_APC_EXT.1/AO Active PSD
Connections
[MOD_AO_V1.0] All
FDP_APC_EXT.1/KM Active PSD
Connections
[MOD_KM_V1.0] All
FDP_APC_EXT.1/VI Active PSD
Connections
[MOD_VI_V1.0] All
FDP_CDS_EXT.1(1) Connected Displays
Supported (1)
[MOD_VI_V1.0] SK21PH-4,
SK41PH-4,
SK81PH-4
FDP_CDS_EXT.1(2) Connected Displays
Supported (2)
[MOD_VI_V1.0] DK22PH-4,
DK42PH-4,
DK82PH-4,
SX42PH-4,
SX82PH-4
FDP_FIL_EXT.1/KM Device Filtering
(Keyboard/Mouse)
[MOD_KM_V1.0] All
FDP_IPC_EXT.1 Internal Protocol
Conversion
[MOD_VI_V1.0] All
FDP_PDC_EXT.1 Peripheral Device [PP_PSD_V4.0] All
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Class Identifier Name Source Applicable
Devices
Connection [MOD_AO_V1.0]3
[MOD_VI_V1.0]4
[MOD_KM_V1.0]5
FDP_PDC_EXT.2/AO Peripheral Device
Connection (Audio
Output)
[MOD_AO_V1.0] All
FDP_PDC_EXT.2/KM Authorized Devices
(Keyboard/Mouse)
[MOD_KM_V1.0] All
FDP_PDC_EXT.2/VI Authorized Devices
(Video Output)
[MOD_VI_V1.0] All
FDP_PDC_EXT.3/KM Authorized
Connection Protocols
(Keyboard/Mouse)
[MOD_KM_V1.0] All
FDP_PDC_EXT.3/VI Authorized
Connection Protocols
(Video Output)
[MOD_VI_V1.0] All
FDP_PUD_EXT.1 Powering [MOD_AO_V1.0] All
3
There is no modification to this SFR in the [MOD_AO_V1.0]. However, there are additions to the Peripheral Device
Connections associated with this SFR and additional evaluation activities.
4
There is no modification to this SFR in the [MOD_VI_V1.0]. However, there are additions to the Peripheral Device
Connections associated with this SFR and additional evaluation activities.
5
There is no modification to this SFR in the [MOD_KM_V1.0]. However, there are additions to the Peripheral Device
Connections associated with this SFR and additional evaluation activities.
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Class Identifier Name Source Applicable
Devices
Unauthorized Devices
FDP_RDR_EXT.1 Re-Enumeration
Device Rejection
[MOD_KM_V1.0] All
FDP_RIP_EXT.1 Residual Information
Protection
[PP_PSD_V4.0] All
FDP_RIP.1/KM Residual Information
Protection (Keyboard
Data)
[MOD_KM_V1.0] All
FDP_SPR_EXT.1/DP Sub-Protocol Rules
(DisplayPort
Protocol)
[MOD_VI_V1.0] All
FDP_SPR_EXT.1/HDMI Sub-Protocol Rules
(HDMI Protocol)
[MOD_VI_V1.0] All
FDP_SWI_EXT.1 PSD Switching [PP_PSD_V4.0] All
FDP_SWI_EXT.2(1) PSD Switching
Methods (1)
[PP_PSD_V4.0]
[MOD_KM_V1.0]6
SK21PH-4,
SK41PH-4,
DK22PH-4,
DK42PH-4,
SK81PH-4,
DK82PH-4
6
There is no modification to this SFR in [MOD_KM_V1.0], and the additional evaluation activities are not triggered by the
selections in FDP_SWI_EXT.2.2(1).
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Class Identifier Name Source Applicable
Devices
FDP_SWI_EXT.2(2) PSD Switching
Methods (2)
[PP_PSD_V4.0]
[MOD_KM_V1.0]7
SX42PH-4,
SX82PH-4
FDP_SWI_EXT.3 Tied Switching [MOD_KM_V1.0] All
FDP_UDF_EXT.1/AO Unidirectional Data
Flow (Audio Output)
[MOD_AO_V1.0] All
FDP_UDF_EXT.1/KM Unidirectional Data
Flow
(Keyboard/Mouse)
[MOD_KM_V1.0] All
FDP_UDF_EXT.1/VI Unidirectional Data
Flow (Video Output)
[MOD_VI_V1.0] All
Protection of
the TSF
(FPT)
FPT_FLS_EXT.1 Failure with
Preservation of
Secure State
[PP_PSD_V4.0] All
FPT_NTA_EXT.1 No Access to TOE [PP_PSD_V4.0] All
FPT_PHP.1 Passive Detection of
Physical Attack
[PP_PSD_V4.0] All
FPT_PHP.3 Resistance to
Physical Attack
[PP_PSD_V4.0] All
7
There is no modification to this SFR in [MOD_KM_V1.0]; however, additional evaluation activities are triggered by the
selections in FDP_SWI_EXT.2.2(2).
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Class Identifier Name Source Applicable
Devices
FPT_TST.1 TSF testing [PP_PSD_V4.0] All
FPT_TST_EXT.1 TSF Testing [PP_PSD_V4.0] All
TOE Access
(FTA)
FTA_CIN_EXT.1 Continuous
Indications
[PP_PSD_V4.0]
[MOD_VI_V1.0]
All
Table 11 – Summary of Security Functional Requirements
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User Data Protection (FDP)
6.2.1.1 FDP_AFL_EXT.1 Audio Filtration
FDP_AFL_EXT.1.1 The TSF shall ensure outgoing audio signals are filtered as per Audio
Filtration Specifications table.
Frequency (kHz) Minimum Voltage (dB) Maximum Voltage After
Attenuation
14 23.9 127.65 mV
15 26.4 95.73 mV
16 30.8 57.68 mV
17 35.0 35.57 mV
18 38.8 22.96 mV
19 43.0 14.15 mV
20 46.0 10.02 mV
30 71.4 0.53 mV
40 71.4 0.53 mV
50 71.4 0.53 mV
60 71.4 0.53 mV
Table 12 – Audio Filtration Specifications
Application Note: TD0557 applies to this SFR definition.
6.2.1.2 FDP_APC_EXT.1/AO Active PSD Connections
FDP_APC_EXT.1.1/AO The TSF shall route user data only from the interfaces selected
by the user.
FDP_APC_EXT.1.2/AO The TSF shall ensure that no data or electrical signals flow
between connected computers whether the TOE is powered on
or powered off.
FDP_APC_EXT.1.3/AO The TSF shall ensure that no data transits the TOE when the
TOE is powered off.
FDP_APC_EXT.1.4/AO The TSF shall ensure that no data transits the TOE when the
TOE is in a failure state.
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6.2.1.3 FDP_APC_EXT.1/KM Active PSD Connections
FDP_APC_EXT.1.1/KM The TSF shall route user data only to the interfaces selected by
the user.
FDP_APC_EXT.1.2/KM The TSF shall ensure that no data or electrical signals flow
between connected computers whether the TOE is powered on
or powered off.
FDP_APC_EXT.1.3/KM The TSF shall ensure that no data transits the TOE when the
TOE is powered off.
FDP_APC_EXT.1.4/KM The TSF shall ensure that no data transits the TOE when the
TOE is in a failure state.
6.2.1.4 FDP_APC_EXT.1/VI Active PSD Connections
FDP_APC_EXT.1.1/VI The TSF shall route user data only from the interfaces selected
by the user.
FDP_APC_EXT.1.2/VI The TSF shall ensure that no data or electrical signals flow
between connected computers whether the TOE is powered on
or powered off.
FDP_APC_EXT.1.3/VI The TSF shall ensure that no data transits the TOE when the
TOE is powered off.
FDP_APC_EXT.1.4/VI The TSF shall ensure that no data transits the TOE when the
TOE is in a failure state.
6.2.1.5 FDP_CDS_EXT.1(1) Connected Displays Supported (1)
FDP_CDS_EXT.1.1(1) The TSF shall support [one connected display] at a time.
Application Note: FDP_CDS_EXT.1(1) applies to the following models: SK21PH-4,
SK41PH-4, SK81PH-4.
6.2.1.6 FDP_CDS_EXT.1(2) Connected Displays Supported (2)
FDP_CDS_EXT.1.1(2) The TSF shall support [multiple connected displays] at a time.
Application Note: FDP_CDS_EXT.1(2) applies to the following models: DK22PH-4,
DK42PH-4, DK82PH-4, SX42PH-4, SX82PH-4.
6.2.1.7 FDP_FIL_EXT.1/KM Device Filtering (Keyboard/Mouse)
FDP_FIL_EXT.1.1/KM The TSF shall have [fixed] device filtering for [keyboard, mouse]
interfaces.
FDP_FIL_EXT.1.2/KM The TSF shall consider all PSD KM blacklisted devices as
unauthorized devices for [keyboard, mouse] interfaces in
peripheral device connections.
FDP_FIL_EXT.1.3/KM The TSF shall consider all PSD KM whitelisted devices as
authorized devices for [keyboard, mouse] interfaces in
peripheral device connections only if they are not on the PSD KM
blacklist or otherwise unauthorized.
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6.2.1.8 FDP_IPC_EXT.1 Internal Protocol Conversion
FDP_IPC_EXT.1.1 The TSF shall convert the DisplayPort protocol at the DisplayPort
computer video interface into the HDMI protocol within the TOE.
FDP_IPC_EXT.1.2 The TSF shall output the HDMI protocol from inside the TOE to
peripheral display interface(s) as [DisplayPort protocol, HDMI
protocol].
Application Note: TD0586 applies to this SFR definition.
6.2.1.9 FDP_PDC_EXT.1 Peripheral Device Connection
FDP_PDC_EXT.1.1 The TSF shall reject connections with unauthorized devices upon
TOE power up and upon connection of a peripheral device to a
powered‐on TOE.
FDP_PDC_EXT.1.2 The TSF shall reject connections with devices presenting
unauthorized interface protocols upon TOE power up and upon
connection of a peripheral device to a powered‐on TOE.
FDP_PDC_EXT.1.3 The TOE shall have no external interfaces other than those claimed
by the TSF.
FDP_PDC_EXT.1.4 The TOE shall not have wireless interfaces.
FDP_PDC_EXT.1.5 The TOE shall provide a visual or auditory indication to the User
when a peripheral is rejected.
6.2.1.10 FDP_PDC_EXT.2/AO Peripheral Device Connection
(Audio Output)
FDP_PDC_EXT.2.1/AO The TSF shall allow connections with authorized devices as
defined in Appendix E [of [MOD_AO_V1.0]] and [
• authorized devices and functions as defined in the PP‐
Module for Keyboard/Mouse Devices,
• authorized devices as defined in the PP‐Module for
Video/Display Devices
] upon TOE power up and upon connection of a peripheral
device to a powered-on TOE.
FDP_PDC_EXT.2.2/AO The TSF shall allow connections with authorized devices
presenting authorized interface protocols as defined in
Appendix E [of [MOD_AO_V1.0]] and [
• authorized devices presenting authorized interface
protocols as defined in the PP‐Module for Keyboard/Mouse
Devices,
• authorized devices presenting authorized interface
protocols as defined in the PP‐Module for Video/Display
Devices
] upon TOE power up and upon connection of a peripheral
device to a powered-on TOE.
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6.2.1.11 FDP_PDC_EXT.2/KM Authorized Devices
(Keyboard/Mouse)
FDP_PDC_EXT.2.1/KM The TSF shall allow connections with authorized devices and
functions as defined in Appendix E [of [MOD_KM_V1.0]] and
[
• authorized devices as defined in the PP‐Module for Audio
Output Devices,
• authorized devices as defined in the PP‐Module for
Video/Display Devices
] upon TOE power up and upon connection of a peripheral
device to a powered-on TOE.
FDP_PDC_EXT.2.2/KM The TSF shall allow connections with authorized devices
presenting authorized interface protocols as defined in
Appendix E [of [MOD_KM_V1.0]] and [
• authorized devices presenting authorized interface
protocols as defined in the PP‐Module for Audio Output
Devices,
• authorized devices presenting authorized interface
protocols as defined in the PP‐Module for Video/Display
Devices
] upon TOE power up and upon connection of a peripheral
device to a powered-on TOE.
6.2.1.12 FDP_PDC_EXT.2/VI Peripheral Device Connection (Video
Output)
FDP_PDC_EXT.2.1/VI The TSF shall allow connections with authorized devices as
defined in Appendix E [of [MOD_VI_V1.0]] and [
• authorized devices as defined in the PP‐Module for Audio
Output Devices,
• authorized devices and functions as defined in the PP‐
Module for Keyboard/Mouse Devices
] upon TOE power up and upon connection of a peripheral
device to a powered-on TOE.
FDP_PDC_EXT.2.2/VI The TSF shall allow connections with authorized devices
presenting authorized interface protocols as defined in
Appendix E [of [MOD_VI_V1.0]] and [
• authorized devices presenting authorized interface
protocols as defined in the PP‐Module for Audio Output
Devices,
• authorized devices presenting authorized interface
protocols as defined in the PP‐Module for Keyboard/Mouse
Devices
] upon TOE power up and upon connection of a peripheral
device to a powered-on TOE.
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6.2.1.13 FDP_PDC_EXT.3/KM Authorized Connection Protocols
(Keyboard/Mouse)
FDP_PDC_EXT.3.1/KM The TSF shall have interfaces for the [USB (keyboard), USB
(mouse)] protocols.
FDP_PDC_EXT.3.2/KM The TSF shall apply the following rules to the supported
protocols: the TSF shall emulate any keyboard or mouse
device functions from the TOE to the connected computer.
6.2.1.14 FDP_PDC_EXT.3/VI Authorized Connection Protocols
(Video Output)
FDP_PDC_EXT.3.1/VI The TSF shall have interfaces for the [HDMI, DisplayPort]
protocols.
FDP_PDC_EXT.3.2/VI The TSF shall apply the following rules to the supported
protocols: the TSF shall read the connected display EDID
information once during power‐on or reboot.
6.2.1.15 FDP_PUD_EXT.1 Powering Unauthorized Devices
FDP_PUD_EXT.1.1 The TSF shall not provide power to any unauthorized device
connected to the analog audio peripheral interface.
6.2.1.16 FDP_RDR_EXT.1 Re-Enumeration Device Rejection
FDP_RDR_EXT.1.1 The TSF shall reject any device that attempts to enumerate again as
a different unauthorized device.
6.2.1.17 FDP_RIP_EXT.1 Residual Information Protection
FDP_RIP_EXT.1.1 The TSF shall ensure that no user data is written to TOE non‐volatile
memory or storage.
6.2.1.18 FDP_RIP.1/KM Residual Information Protection
(Keyboard Data)
FDP_RIP.1.1/KM The TSF shall ensure that any keyboard data in volatile memory is
purged upon switching computers.
6.2.1.19 FDP_SPR_EXT.1/DP Sub-Protocol Rules (DisplayPort
Protocol)
FDP_SPR_EXT.1.1/DP The TSF shall apply the following rules for the DisplayPort
protocol:
• block the following video/display sub‐protocols:
o CEC,
o EDID from computer to display,
o HDCP,
o MCCS
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• allow the following video/display sub‐protocols:
o EDID from display to computer,
o HPD from display to computer,
o Link Training.
6.2.1.20 FDP_SPR_EXT.1/HDMI Sub-Protocol Rules (HDMI
Protocol)
FDP_SPR_EXT.1.1/HDMI The TSF shall apply the following rules for the HDMI
protocol:
• block the following video/display sub‐protocols:
o ARC
o CEC,
o EDID from computer to display,
o HDCP,
o HEAC,
o HEC,
o MCCS
• allow the following video/display sub‐protocols:
o EDID from display to computer,
o HPD from display to computer.
6.2.1.21 FDP_SWI_EXT.1 PSD Switching
FDP_SWI_EXT.1.1 The TSF shall ensure that [switching can be initiated only through
express user action].
6.2.1.22 FDP_SWI_EXT.2(1) PSD Switching Methods (1)
FDP_SWI_EXT.2.1(1) The TSF shall ensure that no switching can be initiated through
automatic port scanning, control through a connected
computer, or control through keyboard shortcuts.
FDP_SWI_EXT.2.2(1) The TSF shall ensure that switching can be initiated only
through express user action using [console buttons].
Application Note: FDP_SWI_EXT.2(1) applies to the following models: SK21PH-4,
SK41PH-4, DK22PH-4, DK42PH-4, SK81PH-4, DK82PH-4.
6.2.1.23 FDP_SWI_EXT.2(2) PSD Switching Methods (2)
FDP_SWI_EXT.2.1(2) The TSF shall ensure that no switching can be initiated through
automatic port scanning, control through a connected
computer, or control through keyboard shortcuts.
FDP_SWI_EXT.2.2(2) The TSF shall ensure that switching can be initiated only
through express user action using [console buttons, peripheral
devices using a guard].
Application Note: FDP_SWI_EXT.2(2) applies to the following models: SX42PH-4,
SX82PH-4.
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6.2.1.24 FDP_SWI_EXT.3 Tied Switching
FDP_SWI_EXT.3.1 The TSF shall ensure that connected keyboard and mouse peripheral
devices are always switched together to the same connected
computer.
6.2.1.25 FDP_UDF_EXT.1/AO Unidirectional Data Flow (Audio
Output)
FDP_UDF_EXT.1.1/AO The TSF shall ensure analog audio output data transits the TOE
unidirectionally from the TOE analog audio output computer
interface to the TOE analog audio output peripheral interface.
6.2.1.26 FDP_UDF_EXT.1/KM Unidirectional Data Flow
(Keyboard/Mouse)
FDP_UDF_EXT.1.1/KM The TSF shall ensure [keyboard, mouse] data transits the TOE
unidirectionally from the TOE [keyboard, mouse] peripheral
interface(s) to the TOE [keyboard, mouse] interface.
6.2.1.27 FDP_UDF_EXT.1/VI Unidirectional Data Flow (Video
Output)
FDP_UDF_EXT.1.1/VI The TSF shall ensure video data transits the TOE
unidirectionally from the TOE computer video interface to the
TOE peripheral device display interface.
Protection of the TSF (FPT)
6.2.2.1 FPT_FLS_EXT.1 Failure with Preservation of Secure State
FPT_FLS_EXT.1.1 The TSF shall preserve a secure state when the following types of
failures occur: failure of the power‐on self‐test and [failure of the
anti-tamper function].
6.2.2.2 FPT_NTA_EXT.1 No Access to TOE
FPT_NTA_EXT.1.1 TOE firmware, software, and memory shall not be accessible via the
TOE’s external ports, with the following exceptions: [the Extended
Display Identification Data (EDID) memory of Video TOEs may
be accessible from connected computers].
6.2.2.3 FPT_PHP.1 Passive Detection of Physical Attack
FPT_PHP.1.1 The TSF shall provide unambiguous detection of physical tampering
that might compromise the TSF.
FPT_PHP.1.2 The TSF shall provide the capability to determine whether physical
tampering with the TSF's devices or TSF's elements has occurred.
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6.2.2.4 FPT_PHP.3 Resistance to Physical Attack
FPT_PHP.3.1 The TSF shall resist a physical attack for the purpose of gaining access
to the internal components, to damage the anti‐tamper battery, to drain
or exhaust the anti‐tamper battery to the TOE enclosure by becoming
permanently disabled.
6.2.2.5 FPT_TST.1 TSF Testing
FPT_TST.1.1 The TSF shall run a suite of self-tests during initial start-up and at the
conditions [no other conditions] to demonstrate the correct operation of
user control functions and [active anti-tamper functionality].
FPT_TST.1.2 The TSF shall provide authorized users with the capability to verify the
integrity of [TSF data].
FPT_TST.1.3 The TSF shall provide authorized users with the capability to verify the
integrity of [TSF].
6.2.2.6 FPT_TST_EXT.1 TSF Testing
FPT_TST_EXT.1.1 The TSF shall respond to a self‐test failure by providing users with a
[visual, auditory] indication of failure and by shutdown of normal
TSF functions.
TOE Access (FTA)
6.2.3.1 FTA_CIN_EXT.1 Continuous Indications
FTA_CIN_EXT.1.1 The TSF shall display a visible indication of the selected computers
at all times when the TOE is powered.
FTA_CIN_EXT.1.2 The TSF shall implement the visible indication using the following
mechanism: easily visible graphical and/or textual markings of each
source video on the display, [[illuminated buttons]].
FTA_CIN_EXT.1.3 The TSF shall ensure that while the TOE is powered the current
switching status is reflected by [multiple indicators which never
display conflicting information].
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7 SECURITY ASSURANCE REQUIREMENTS
The assurance requirements are summarized in Table 13.
Assurance Class
Assurance Components
Identifier Name
Development (ADV) ADV_FSP.1 Basic Functional Specification
Guidance Documents
(AGD)
AGD_OPE.1 Operational user guidance
AGD_PRE.1 Preparative procedures
Life-Cycle Support
(ALC)
ALC_CMC.1 Labeling of the TOE
ALC_CMS.1 TOE CM Coverage
Security Target
Evaluation (ASE)
ASE_CCL.1 Conformance claims
ASE_ECD.1 Extended Components Definition
ASE_INT.1 ST Introduction
ASE_OBJ.2 Security Objectives
ASE_REQ.2 Derived Security Requirements
ASE_SPD.1 Security Problem Definition
ASE_TSS.1 TOE Summary Specification
Tests (ATE)
ATE_IND.1
Independent Testing -
Conformance
Vulnerability
Assessment (AVA)
AVA_VAN.1 Vulnerability Survey
Table 13 – Security Assurance Requirements
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8 SECURITY REQUIREMENTS RATIONALE
8.1 SECURITY FUNCTIONAL REQUIREMENTS
RATIONALE
Table 7 provides a mapping between the SFRs and Security Objectives.
8.2 DEPENDENCY RATIONALE
Table 14 identifies the Security Functional Requirements and their associated
dependencies. It also indicates whether the ST explicitly addresses each
dependency.
SFR Dependencies Rationale Statement
FDP_AFL_EXT.1 FDP_PDC_EXT.1 Included
FDP_APC_EXT.1/AO None N/A
FDP_APC_EXT.1/KM None N/A
FDP_APC_EXT.1/VI None N/A
FDP_CDS_EXT.1(1) None N/A
FDP_CDS_EXT.1(2) None N/A
FDP_FIL_EXT.1/KM FDP_PDC_EXT.1 Included
FDP_IPC_EXT.1 FDP_PDC_EXT.2 Included
FDP_PDC_EXT.1 None N/A
FDP_PDC_EXT.2/AO FDP_PDC_EXT.1 Included
FDP_PDC_EXT.2/KM FDP_PDC_EXT.1 Included
FDP_PDC_EXT.2/VI FDP_PDC_EXT.1 Included
FDP_PDC_EXT.3/KM FDP_PDC_EXT.1 Included
FDP_PDC_EXT.3/VI FDP_PDC_EXT.1 Included
FDP_PUD_EXT.1 FDP_PDC_EXT.1 Included
FDP_RDR_EXT.1 FDP_PDC_EXT.1 Included
FDP_RIP_EXT.1 None N/A
FDP_RIP.1/KM None N/A
FDP_SPR_EXT.1/DP FDP_PDC_EXT.3 Included
FDP_SPR_EXT.1/HDMI FDP_PDC_EXT.3 Included
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SFR Dependencies Rationale Statement
FDP_SWI_EXT.1 None N/A
FDP_SWI_EXT.2(1) FDP_SWI_EXT.1 Included
FDP_SWI_EXT.2(2) FDP_SWI_EXT.1 Included
FDP_SWI_EXT.3 FDP_SWI_EXT.1 Included
FDP_UDF_EXT.1/AO FDP_APC_EXT.1 Included
FDP_UDF_EXT.1/KM FDP_APC_EXT.1 Included
FDP_UDF_EXT.1/VI FDP_APC_EXT.1 Included
FPT_FLS_EXT.1 FPT_TST.1
FPT_PHP.3
Included
Included only if anti‐tamper is selected in
FPT_FLS_EXT.1.1
FPT_NTA_EXT.1 None N/A
FPT_PHP.1 None N/A
FPT_PHP.3 None N/A
FPT_TST.1 None N/A
FPT_TST_EXT.1 FPT_TST.1 Included
FTA_CIN_EXT.1 FDP_APC_EXT.1 Included
Table 14 – Functional Requirement Dependencies
8.3 SECURITY ASSURANCE REQUIREMENTS
RATIONALE
The TOE assurance requirements for this ST consist of the requirements
indicated in the [PP_PSD_V4.0].
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9 TOE SUMMARY SPECIFICATION
This section provides a description of the security functions and assurance
measures of the TOE that meet the TOE security requirements. Unless otherwise
stated, the description applies to all devices.
9.1 USER DATA PROTECTION
System Controller
Each device includes a System Controller which is responsible for device
management, user interaction, system control security functions, and device
monitoring. It receives user input from the switches on the front panel a
peripheral device using a guard (for the SX42PH-4 and SX82PH-4 devices), and
drives the TOE channel select lines that control switching circuits within the TOE.
The System Controller includes a microcontroller with internal non-volatile, Read
Only Memory (ROM). The controller function manages the TOE functionality
through a pre-programmed state machine loaded on the ROM as read-only
firmware during product manufacturing.
Following boot up of the TOE, the channel select lines are set to Channel 1 by
default. The channel select lines are also used to link the System Controller
channel select commands to the Field Programmable Gate Array (FPGA) that
supports video processing.
The user determines the host computer to be connected to the peripherals by
pressing a button on the TOE front panel. The front panel button of the selected
computer is illuminated. Switching can only be initiated through express user
action and not through automated port scanning, connected computer control,
or keyboard shortcuts.
KVM Matrix devices (SX42PH-4, SX82PH-4) may be switched with peripheral
devices using a guard8
. This is done by moving the mouse to the edge of the
screen while pressing the left CTRL key.
TOE Security Functional Requirements addressed: FDP_SWI_EXT.1,
FDP_SWI_EXT.2(1), FDP_SWI_EXT.2(2).
9.1.1.1 Active PSD Connections
The TOE ensures that data flows only between the peripherals and the
connected computer selected by the user. The TOE ensures that no electrical
signal flows between the connected computers selected by the user. No data
transits the TOE when the TOE is powered off, or when the TOE is in a failure
state. A failure state occurs when the TOE fails a self-test when powering on, or
when the anti-tampering function has been triggered.
8
See Section 10.1 or [PP_PSD_V4.0] for the definition of a guard.
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TOE Security Functional Requirements addressed: FDP_APC_EXT.1/AO,
FDP_APC_EXT.1/KM, FDP_APC_EXT.1/VI.
9.1.1.2 Connected Computer Interfaces
The connected computers are attached to the TOE as follows:
• The TOE connects to the keyboard and mouse port using a USB A to USB
B cable. The USB A end attaches to the computer, and the USB B end
attaches to the TOE
• The TOE is connected to the computer video port using a video cable
supporting DisplayPort or HDMI
• The TOE audio-in is connected to the computer audio-out using a 1/8”
stereo plug cable
There are no wireless interfaces or additional external interfaces
TOE Security Functional Requirements addressed: FDP_PDC_EXT.1.
9.1.1.3 Residual Information Protection
The Letter of Volatility is included as Annex A.
TOE Security Functional Requirements addressed: FDP_RIP_EXT.1.
Keyboard and Mouse Functionality
9.1.2.1 Keyboard and Mouse Enumeration
The TOE determines whether or not a peripheral device that has been plugged
into the keyboard and mouse peripheral ports is allowed to operate with the
TOE. The TOE uses optical data diodes to enforce a unidirectional data flow from
the user peripherals to the coupled hosts, and uses isolated device emulators to
prevent data leakage through the peripheral switching circuitry.
The Static Random Access Memory (SRAM) in the host and device emulator
circuitry stores USB Host stack parameters and up to the last 4 key codes. User
data may be briefly retained; however, there are no data buffers. Data is erased
during power off of the KVM, and when the user switches channels. When the
TOE switches from one computer to another, the system controller ensures that
the keyboard and mouse stacks are deleted, and that any data received from
the keyboard in the first 100 milliseconds following switching is deleted. This is
done to ensure that any data buffered in the keyboard microcontroller is not
passed to the newly selected computer.
The TOE supports USB Type A HIDs on keyboard and mouse ports. The USB
bidirectional communication protocol is converted into a unidirectional
proprietary protocol, and is then converted back into the USB bidirectional
protocol to communicate with the coupled computer hosts.
A USB keyboard is connected to the TOE keyboard host emulator through the
console keyboard port. The keyboard host emulator is a microcontroller which
enumerates the connected keyboard and verifies that it is a permitted device
type. Once the keyboard has been verified, the USB keyboard sends scan codes,
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which are generated when the user types. These scan codes are converted by
the keyboard host emulator into a proprietary protocol data stream that is
combined with the data stream from the mouse host emulator.
Similarly, the USB mouse is connected to the TOE mouse host emulator through
the USB mouse port. The mouse host emulator is a microcontroller which
enumerates the connected mouse and verifies that it is a permitted device type.
Once the mouse device has been verified, it sends serial data generated by
mouse movement and button use. The mouse serial data is converted by the
mouse host emulator into a proprietary protocol data stream that is combined
with the data stream from the keyboard host emulator.
TOE Security Functional Requirements addressed: FDP_PDC_EXT.3/KM,
FDP_UDF_EXT.1/KM, FDP_RIP.1/KM.
9.1.2.2 Keyboard and Mouse Switching Functionality
Figure 2 is a simplified block diagram showing the TOE keyboard and mouse
data path for two ports. A Host Emulator (HE) communicates with the user
keyboard via the USB protocol. The Host Emulator converts user key strokes
into unidirectional serial data.
Figure 2 – Simplified Switching Diagram
The combined data stream is passed through the channel select lines to the
selected host channel. The channel select lines are driven by the System
Controller Module, and the selection is based on user input through use of the
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mouse or keyboard. Once a channel is selected, the combined mouse and
keyboard data stream is passed through an optical data diode and routed to the
specific host channel device emulator. The optical data diode is an opto-coupler
designed to physically prevent reverse data flow. The keyboard and mouse can
only be switched together.
Device Emulators (DEs) are USB enabled microcontrollers that are programmed
to emulate a standard USB keyboard and mouse composite device. The
combined data stream is converted back to bidirectional data before reaching
the selected host computer.
Since the keyboard and mouse function are emulated by the TOE, the connected
computer is not able to send data to the keyboard that would allow it to indicate
that Caps Lock, Num Lock or Scroll Lock are set. These are indicated on the TOE
front panel, on the right-hand side, as shown in Figure 6 in Section 9.3.
TOE Security Functional Requirements addressed: FDP_APC_EXT.1/KM,
FDP_UDF_EXT.1/KM, FDP_SWI_EXT.3.
9.1.2.3 Keyboard and Mouse Compatible Device Types
The TOE employs fixed device filtering and accepts only USB HID devices at the
keyboard and mouse peripheral ports. Only USB Type A connections are
permitted. The TOE does not support a wireless connection to a mouse,
keyboard or USB hub and there are no additional external interfaces.
TOE Security Functional Requirements addressed: FDP_PDC_EXT.1,
FDP_PDC_EXT.2/KM, FDP_FIL_EXT.1/KM.
9.1.2.4 Re-Enumeration Device Rejection
If a connected device attempts to re-enumerate as a different USB device type,
it will be rejected by the TOE. The TOE will reject devices which are not allowed
at any time during operation and start-up. This is indicated by an LED on the
TOE next to the Keyboard and mouse ports. This LED shows a solid green light
for an accepted device, flickering green light during enumeration, and no light
for a rejected device.
TOE Security Functional Requirements addressed: FDP_RDR_EXT.1.
Video Switching Functionality
Video data flow is comprised of unidirectional Extended Display Identification
Data (EDID) and video data flow path and goes from the TOE computer video
interface to the TOE peripheral device display interface. Figure 3 shows a data
flow during the display EDID read function.
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Figure 3 – Display EDID Read Function
An EDID read event only occurs as the TOE is being powered up. The video
controller reads the EDID content from the display device to verify that it is valid
and usable. If data is not valid, TOE operation will cease and wait for the display
peripheral to be changed.
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Figure 4 – Display EDID Write Function
Figure 4 illustrates the video controller (shown in blue) as it writes the EDID
content into the first channel emulated EDID Electrically Erasable Programmable
Read-Only Memory (EEPROM) chip (shown in gray). The thick lines in this figure
indicate native video lines, and the thin lines indicate Inter-Integrated Circuit
(I2C) lines. The EDID multiplexer couples the I2C lines to the first EDID mode
switch (shown in orange). The first EDID mode switch switches the video
controller I2C lines to the first emulated EDID EEPROM chip (shown in gray).
The chip write protect switch opens to enable writing. The video controller uses
the I2C lines to write to the first emulated EDID EEPROM chip. Once the write
operation is complete and verified, the video controller switches the EDID
multiplexer to the next channel and the operation repeats until all chips are
programmed. Once the write operation is complete, the video controller switches
to normal operating mode, as shown in Figure 5 below.
In EDID write mode, the Emulated EDID EEPROM chips are switched to their
respective computers to enable reading of the EDID information. The write
protect switches are switched back to protected mode to prevent any attempt to
write to the EEPROM or to transmit MCCS commands.
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Figure 5 – Display Normal Mode
In normal mode, each computer interface operates independently. The power to
each emulated EDID EEPROM is received from its respective computer through
the video cable. The main video multiplexer is switched to the user selected
computer to enable the proper video display.
During TOE normal operation (Figure 5), any attempt by a connected computer
to affect the EDID channel is blocked by the architecture. Each computer is only
able to affect its own emulated EDID EEPROM.
Video input interfaces are isolated from one another. Isolation is achieved
through the use of separate power and ground planes, separate electronic
components and a separate emulated EDID chip for each channel.
The EDID function is emulated by an independent emulation EEPROM chip for
each computer channel. These chips read content from the connected display
once during TOE power up. Any subsequent change to the display peripheral will
be ignored.
The TOE will reject any display device that does not present valid EDID content.
An LED on the rear panel of the TOE will indicate a rejected display device.
The TOE supports DisplayPort versions 1.1, 1.2 and 1.3, and HDMI 2.0:
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• For DisplayPort connections, the TOE video function filters the AUX
channel by converting it to I2C EDID only. DisplayPort video is converted
into an HDMI video stream, and the I2C EDID lines connected to the
emulated EDID EEPROM functions as shown in the figures above. This
allows EDID to be passed from the display to the computer (as described
above), and allows Hot-Plug Detection (HPD) and Link Training
information to pass through the TOE. AUX channel threats are mitigated
through the conversion from DisplayPort to HDMI protocols. Traffic types
including USB, Ethernet, MCCS, and EDID write from the computer to the
display are blocked by the TOE. High-bandwidth Digital Content Protection
(HDCP) and Consumer Electronics Control (CEC) functions are not
connected
• For HDMI connections, EDID information is allowed to pass from the
display to the computer, as described above. HPD information is also
allowed to pass. Other protocols, including Audio Return Channel (ARC),
EDID from the computer to the display, HDMI Ethernet and Audio Return
Channel (HEAC), and HDMI Ethernet Channel (HEC) are blocked. HDCP
and Consumer Electronics Control (CEC) functions are not connected
The TOE video function blocks MCCS write transactions through the emulated
EDID EEPROMs. The emulated EEPROMs support only EDID read transactions,
and are isolated by the write protect switch.
Following triggering of the anti-tampering function, following a failed self-test, or
when the TOE is powered off, all video input signals are isolated from other
video inputs and from the video output interfaces by the active video re-drivers.
Emulated EDID EEPROMs may still operate since they are powered by their
respective computers; however, the video function remains isolated.
TOE Security Functional Requirements addressed: FDP_IPC_EXT.1,
FDP_SPR_EXT.1/DP, FDP_SPR_EXT.1/HDMI, FDP_UDF_EXT.1/VI.
9.1.3.1 Video Compatible Device Types
The TOE accepts any DisplayPort of HDMI display device at the video peripheral
ports. The TOE does not support a wireless connection to a video display and
there are no additional external interfaces.
The SK21PH-4, SK41PH-4 and SK81PH-4 devices support a single display. The
DK22PH-4, DK42PH-4, DK82PH-4, SX42PH-4, and SX82PH-4 devices support
two displays.
TOE Security Functional Requirements addressed: FDP_PDC_EXT.1,
FDP_PDC_EXT.2/VI, FDP_PDC_EXT.3/VI, FDP_CDS_EXT.1(1),
FDP_CDS_EXT.1(2).
Audio Switching Functionality
The TOE audio data flow path is electrically isolated from all other functions and
interfaces to prevent signaling data leakages to and from the audio paths.
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Audio switching is controlled by the system controller function through dedicated
unidirectional command lines. Audio signals cannot be digitized or otherwise
sampled by any TOE circuitry. The TOE audio switching multiplexer uses a
combination of mechanical relays and a solid-state multiplexer to ensure
isolation. Unidirectional flow data diodes prevent audio data flow from an audio
device to a selected computer. There is a separate audio interface for each
computer. Each interface is electrically isolated from other interfaces, and from
other TOE circuitry. These features ensure that the audio filtration specification
requirements are met and that the audio signal is filtered according to the
parameters set in Table 12.
The TOE does not supply power to the analog audio output interface, and cannot
be configured to do so. Therefore, it cannot be used to supply power to an
unauthorized device on that interface.
When the TOE is powered off, an audio isolation relay is open, thereby isolating
the audio input from the computer interfaces from all other circuitry and
interfaces. Following triggering of the anti-tampering function, or following a
failed self-test, the TOE will de-energize this audio isolation relay to isolate the
audio inputs. The audio subsystem does not store, convert or delay audio data
flows. Therefore, there is no risk of audio overflow when switching between
channels.
The audio switching functionality features a separate channel selection control
with an optional freeze function. This allows the audio port to stay connected to
a specific computer while switching keyboard, video, and mouse between other
computers.
The use of analog microphone or line-in audio devices is strictly prohibited as
indicated in the user guidance. The TOE will reject a microphone through the
following two methods:
• There is an analog audio data diode that forces data to flow only from a
computer to an audio peripheral device
• There is a microphone Direct Current (DC) bias barrier that blocks an
electret microphone DC bias if the TOE is deliberately or inadvertently
connected to the microphone input jack of a connected computer
TOE Security Functional Requirements addressed: FDP_AFL_EXT.1,
FDP_PUD_EXT.1, FDP_UDF_EXT.1/AO.
9.1.4.1 Audio Compatible Device Types
The TOE accepts analog headphones or analog speakers connected via a 1/8”
(3.5mm) audio jack at the audio peripheral port. The TOE does not support a
wireless connection to an audio output device and there are no additional
external interfaces.
TOE Security Functional Requirements addressed: FDP_PDC_EXT.1,
FDP_PDC_EXT.2/AO.
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9.2 PROTECTION OF THE TSF
No Access to TOE
Connected computers do not have access to TOE firmware or memory, with the
following exceptions:
• EDID data is accessible to connected computers from the TOE.
All of the TOE microcontrollers run from internal protected flash memory.
Firmware cannot be updated from an external source. Firmware cannot be read
or rewritten through the use of Joint Test Action Group (JTAG) tools. Firmware is
executed on Static Random Access Memory (SRAM) with the appropriate
protections to prevent external access and tampering of code or stacks.
TOE Security Functional Requirements addressed: FPT_NTA_EXT.1.
Anti-tampering Functionality
The TOE provides both passive and active anti-tampering functionality.
9.2.2.1 Passive Detection of Physical Tampering
The TOE enclosure was designed specifically to prevent physical tampering. It
features a stainless-steel welded chassis and panels that prevent external access
through bending or brute force.
Additionally, each device is fitted with one or more holographic Tampering
Evident Labels placed at critical locations on the TOE enclosure. If the label is
removed, the word ‘VOID’ appears on both the label and the product surface.
TOE Security Functional Requirements addressed: FPT_PHP.1.
9.2.2.2 Resistance to Physical Attack
The anti-tampering system is mechanically coupled to the TOE enclosure to
detect any attempt to access the TOE internal circuitry. Any attempt to separate
the pieces of the enclosure to access the internal circuitry will trigger the anti-
tampering function. Power is provided to the circuitry by the TOE power supply
and by a backup battery. If the self-test detects that the battery is depleted or
failing, the anti-tampering function will be triggered.
When the anti-tampering function is triggered, it causes an internal microscopic
fuse on the System Controller (on-die) to melt. This permanently disables all
interfaces and user functions of the device, and causes the front panel LEDs to
blink sequentially and continuously. The TOE anti-tampering function is
irreversible.
TOE Security Functional Requirements addressed: FPT_FLS_EXT.1, FPT_PHP.3.
TSF Testing
The TOE performs a self-test at initial start-up. The self-test runs independently
at each microcontroller and performs the following checks:
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• Verification of the front panel push-buttons
• Verification of the active anti-tampering functionality, including the
continued functionality of the backup battery
• Verification of the integrity of the microcontroller firmware
• Verification of computer port isolation. This is tested by sending test
packets to various interfaces and attempting to detect this traffic at all
other interfaces
If the self-test fails, the LEDs on the front panel blink and the device makes a
clicking sound to indicate the failure. The TOE disables the PSD switching
functionality, and remains in a disabled state until the self-test is rerun and
passes.
TOE Security Functional Requirements addressed: FPT_FLS_EXT.1, FPT_TST.1,
FPT_TST_EXT.1.
9.3 TOE ACCESS
The TOE user switches between computers by pressing the corresponding front
panel button on the device. The front panel button of the KVM/Matrix or the
remote control button corresponding to the selected computer will illuminate.
When switching between computers with audio output connections, the speakers
or headphones are switched accordingly. When switching to a computer that is
not connected to an audio output device, the audio output device will remain
mapped to the last channel that supported the connection. A user can select the
‘Freeze Audio’ button on the front panel to lock the audio output device to the
currently connected computer. When the user switches the other peripherals to
another channel, the audio output device will remain attached to the previously
selected channel, and the ‘Freeze Audio’ LED will be illuminated. The audio
output device channel is indicated by an LED to the left of the channel. To
release the freeze, the user selects ‘Freeze Audio’ a second time.
Figure 6 shows the selection buttons.
Figure 6 – Channel Selection
On power up or power up following reset, all peripherals are connected to
channel #1, and the corresponding push button LED will be illuminated.
TOE Security Functional Requirements addressed: FTA_CIN_EXT.1.
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10TERMINOLOGY AND ACRONYMS
10.1 TERMINOLOGY
The following terminology is used in this ST:
Term Description
AO AO refers to the requirements for Audio Output Devices.
AUX AUX refers to the auxiliary channel, particularly as it applies to
the DisplayPort protocol.
Guard 'Guard' refers to a peripheral sharing device function that
requires multiple express user actions in order to switch
between connected computers using connected peripherals.
KM KM refers to the requirements for Keyboard/Mouse Devices.
VI VI refers to the requirements for Video/Display Devices.
Table 15 – Terminology
10.2 ACRONYMS
The following acronyms are used in this ST:
Acronym Definition
ARC Audio Return Channel
CC Common Criteria
CEC Consumer Electronics Control
dB decibel
DC Direct Current
DE Device Emulator
EDID Extended Display Identification Data
EEPROM Electrically Erasable Programmable Read-Only Memory
FPGA Field Programmable Gate Array
HDCP High-bandwidth Digital Content Protection
HDMI High-Definition Multimedia Interface
HE Host Emulator
HEAC HDMI Ethernet and Audio Return Channel
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Acronym Definition
HEC HDMI Ethernet Channel
HID Human Interface Device
HPD Hot-Plug Detection
HSL High Sec Labs
I2C Inter-Integrated Circuit
ID Identification
IT Information Technology
JTAG Joint Test Action Group
kHz kilohertz
KVM Keyboard, Video, Mouse
LED Light Emitting Diode
MCCS Monitor Control Command Set
mV millivolt
NIAP National Information Assurance Partnership
OTP One Time Programming
PP Protection Profile
PSD Peripheral Sharing Device
RAM Random Access Memory
RFD Restore to Factory Default
ROM Read Only Memory
SFR Security Functional Requirement
SRAM Static Random Access Memory
ST Security Target
TOE Target of Evaluation
TSF TOE Security Functionality
USB Universal Serial Bus
Table 16 – Acronyms
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11REFERENCES
Identifier Title
[CC] Common Criteria for Information Technology Security
Evaluation –
• Part 1: Introduction and General Model, CCMB‐2017‐
04‐001, Version 3.1 Revision 5, April 2017
• Part 2: Security Functional Components, CCMB‐2017‐
04‐002, Version 3.1 Revision 5, April 2017
• Part 3: Security Assurance Components, CCMB‐2017‐
04‐003, Version 3.1 Revision 5, April 2017
[CEM] Common Methodology for Information Technology Security
Evaluation, Evaluation Methodology, CCMB‐2017‐04‐004,
Version 3.1 Revision 5, April 2017
[PP_PSD_V4.0] Protection Profile for Peripheral Sharing Device, Version: 4.0,
2019‐07‐19
[MOD_AO_V1.0] PP‐Module for Analog Audio Output Devices, Version 1.0,
2019-07-19
[MOD_KM_V1.0] PP‐Module for Keyboard/Mouse Devices, Version 1.0, 2019-
07-19
[MOD_VI_1.0] PP‐Module for Video/Display Devices, Version 1.0, 2019-07-19
[CFG_PSD‐AO‐KM‐
VI_V1.0]
PP‐Configuration for Peripheral Sharing Device, Analog Audio
Output Devices, Keyboard/Mouse Devices, and Video/Display
Devices, 19 July 2019
Table 17 – References
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ANNEX A – LETTER OF VOLATILITY
The table below provides volatility information and memory types for the High Sec Labs Peripheral Sharing Devices with
Keyboard, Video, Mouse and Audio. User data is not retained in any TOE device when the power is turned off.
Product
Model
No. in
each
product
Function,
Manufacturer
and Part
Number
Storage Type Size Power Source
(if not the TOE)
Volatility Contains User Data
SK41PH-4
DK42PH-4
1 System Controller,
Host emulators:
ST Microelectronics
STM32F446ZCT
Embedded SRAM1
128KB Connected computer Volatile May contain user data
Embedded Flash2
256KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
OTP Memory 512bytes Non-Volatile No user data
5 in single
head or
10 in dual
head
models
Video Controller:
ST Microelectronics
STM32F070C6T6
Embedded SRAM1
6KB Connected computer Volatile No user data
Embedded Flash2
32KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
4 Device emulators:
ST Microelectronics
STM32F070C6T6
Embedded SRAM1
6KB Connected computer Volatile May contain user data
Embedded Flash2
32KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
SX42PH-4
SX82PH-4
1 System Controller,
Host emulators:
ST Microelectronics
STM32F446ZCT
Embedded SRAM1
128KB Connected computer Volatile May contain user data
Embedded Flash2
256KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
OTP Memory 512bytes Non-Volatile No user data
5 in 4 port
or 9 in 8
port
models
Video Controller:
ST Microelectronics
STM32F070C6T6
Embedded SRAM1
16KB Connected computer Volatile No user data
Embedded Flash2
128KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
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Product
Model
No. in
each
product
Function,
Manufacturer
and Part
Number
Storage Type Size Power Source
(if not the TOE)
Volatility Contains User Data
4 in 4 port
or 8 in 8
port
Device emulators:
ST Microelectronics
STM32F070C6T6
Embedded SRAM1
16KB Connected computer Volatile May contain user data
Embedded Flash2
128KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
SK21PH-4
DK22PH-4
1 System Controller,
Host emulators:
ST Microelectronics
STM32F446ZCT
Embedded SRAM1
128KB Connected computer Volatile May contain user data
Embedded Flash2
256KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
OTP Memory 512bytes Non-Volatile No user data
3 in single
head or 6
in dual
head
models
Video Controller:
ST Microelectronics
STM32F070C6T6
Embedded SRAM1
16KB Connected computer Volatile No user data
Embedded Flash2
128KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
8 Device emulators:
ST Microelectronics
STM32F070C6T6
Embedded SRAM1
16KB Connected computer Volatile May contain user data
Embedded Flash2
128KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
SK81PH-4
DK82PH-4
1 System Controller,
Host emulators:
ST Microelectronics
STM32F446ZCT
Embedded SRAM1
128KB Connected computer Volatile May contain user data
Embedded Flash2
256KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
OTP Memory 512bytes Non-Volatile No user data
9 in single
head or
18 in dual
head
models
Video Controller:
ST Microelectronics
STM32F070C6T6
Embedded SRAM1
6KB Connected computer Volatile No user data
Embedded Flash2
32KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
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Product
Model
No. in
each
product
Function,
Manufacturer
and Part
Number
Storage Type Size Power Source
(if not the TOE)
Volatility Contains User Data
8 Device emulators:
ST Microelectronics
STM32F070C6T6
Embedded SRAM1
6KB Connected computer Volatile May contain user data
Embedded Flash2
32KB Non-Volatile No user data
Embedded EEPROM 4KB Non-Volatile No user data
Notes:
1
SRAM stores USB Host stack parameters and up to the last 4 key-codes. Data is erased during power off of the KVM, and when the user
switches channels. Device emulators receive power from the individual connected computers and therefore devices are powered on as
long as the associated computer is powered on and connected.
2
Flash storage is used to store firmware code. It contains no user data. Flash storage is permanently locked by fuses after initial
programming to prevent rewriting. It is an integral part of the ST Microcontroller together with SRAM and EEPROM.