National Information Assurance Partnership
Common Criteria Evaluation and Validation Scheme
Validation Report
for the
Cellcrypt Classified 2
Report Number: CCEVS-VR-VID10929
Dated: 22 April 2019
Version: 1.0
National Institute of Standards and Technology National Security Agency
Information Technology Laboratory Information Assurance Directorate
100 Bureau Drive 9800 Savage Road STE 6940
Gaithersburg, MD 20899 Fort George G. Meade, MD 20755-6940
®
TM
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ACKNOWLEDGEMENTS
Validation Team
Jim Donndelinger
Ken Elliott
Ken Stutterheim
The Aerospace Corporation
Common Criteria Testing Laboratory
Danielle F Canoles
Kenji Yoshino
Rutwij Kulkarni
Acumen Security, LLC
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Table of Contents
1 Executive Summary ........................................................................................................ 4
2 Identification.................................................................................................................. 5
3 Architectural Information ............................................................................................... 6
4 Security Policy ................................................................................................................ 7
5 Assumptions, Threats & Clarification of Scope ................................................................ 8
5.1 Assumptions .............................................................................................................................................8
5.2 Threats......................................................................................................................................................8
5.3 Clarification of Scope ................................................................................................................................9
6 Documentation............................................................................................................. 10
7 TOE Evaluated Configuration ........................................................................................ 11
7.1 Evaluated Configuration..........................................................................................................................11
8 IT Product Testing......................................................................................................... 12
8.1 Developer Testing ...................................................................................................................................12
8.2 Evaluation Team Independent Testing ....................................................................................................12
9 Results of the Evaluation .............................................................................................. 13
9.1 Evaluation of Security Target ..................................................................................................................13
9.2 Evaluation of Development Documentation ...........................................................................................13
9.3 Evaluation of Guidance Documents.........................................................................................................13
9.4 Evaluation of Life Cycle Support Activities...............................................................................................14
9.5 Evaluation of Test Documentation and the Test Activity.........................................................................14
9.6 Vulnerability Assessment Activity ...........................................................................................................14
9.7 Summary of Evaluation Results...............................................................................................................15
10 Validator Comments & Recommendations.................................................................... 16
11 Annexes ....................................................................................................................... 17
12 Security Target ............................................................................................................. 18
13 Glossary ....................................................................................................................... 19
14 Bibliography ................................................................................................................. 20
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1 Executive Summary
This Validation Report (VR) is intended to assist the end user of this product and any security
certification Agent for that end user in determining the suitability of this Information Technology (IT)
product for their environment. End users should review the Security Target (ST), which is where specific
security claims are made, in conjunction with this VR, which describes how those security claims were
tested and evaluated and any restrictions on the evaluated configuration. Prospective users should
carefully read the Assumptions and Clarification of Scope in Section 5 and the Validator Comments in
Section 10, where any restrictions on the evaluated configuration are highlighted.
This report documents the National Information Assurance Partnership (NIAP) assessment of the
evaluation of the Cellcrypt Classified 2 Target of Evaluation (TOE). It presents the evaluation results,
their justifications, and the conformance results. This VR is not an endorsement of the TOE by any
agency of the U.S. Government and no warranty of the TOE is either expressed or implied. This VR
applies only to the specific version and configuration of the product as evaluated and documented in the
ST.
The evaluation was completed by Acumen Security in April 2019. The information in this report is
largely derived from the proprietary Evaluation Technical Report (ETR) and associated test report, all
written by Acumen Security as summarized in the Cellcrypt Classified 2 Assurance Activity Report. The
evaluation determined that the product is both Common Criteria Part 2 Extended and Part 3
Conformant, and meets the assurance requirements defined in the Protection Profile for Application
Software Version 1.2 [App] and Extended Package for Voice and Video over IP VVoIP Version 1.0
[VVoIP].
The Target of Evaluation (TOE) identified in this Validation Report has been evaluated at a NIAP
approved Common Criteria Testing Laboratory using the Common Methodology for IT Security
Evaluation (Version 3.1, Rev. 4) for conformance to the Common Criteria for IT Security Evaluation
(Version 3.1, Rev. 4), as interpreted by the Assurance Activities contained in the Protection Profile for
Application Software Version 1.2 [App] and Extended Package for Voice and Video over IP VVoIP
Version 1.0 [VVoIP] and all applicable NIAP technical decisions for the technology. This Validation
Report applies only to the specific version of the TOE as evaluated. The evaluation has been conducted
in accordance with the provisions of the NIAP Common Criteria Evaluation and Validation Scheme and
the conclusions of the testing laboratory in the evaluation technical report are consistent with the
evidence provided.
The validation team provided guidance on technical issues and evaluation processes and reviewed the
individual work units documented in the ETR and the Assurance Activities Report (AAR). The validation
team found that the evaluation showed that the product satisfies all of the functional requirements and
assurance requirements stated in the Security Target (ST). Based on these findings, the validation team
concludes that the testing laboratory's findings are accurate, the conclusions justified, and the
conformance results are correct. The conclusions of the testing laboratory in the evaluation technical
report are consistent with the evidence produced.
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2 Identification
The CCEVS is a joint National Security Agency (NSA) and National Institute of Standards effort to
establish commercial facilities to perform trusted product evaluations. Under this program, security
evaluations are conducted by commercial testing laboratories called Common Criteria Testing
Laboratories (CCTLs). CCTLs evaluate products against Protection Profile containing Assurance
Activities, which are interpretation of CEM work units specific to the technology described by the
PP.
The NIAP Validation Body assigns Validators to monitor the CCTLs to ensure quality and consistency
across evaluations. Developers of information technology products desiring a security evaluation
contract with a CCTL and pay a fee for their product's evaluation. Upon successful completion of the
evaluation, the product is added to NIAP's Product Compliance List.
The target of evaluation is the Cellcrypt Classified 2 and the associated TOE guidance documentation.
Table 1 provides information needed to completely identify the product, including:
 The Target of Evaluation (TOE): the fully qualified identifier of the product as evaluated.
 The Security Target (ST), describing the security features, claims, and assurances of the product.
 The conformance result of the evaluation.
 The Protection Profile(s) to which the product is conformant.
 The organizations and individuals participating in the evaluation.
Table 1 - Identification
Item Identifier
Evaluation Scheme United States NIAP Common Criteria Evaluation and Validation Scheme
TOE Cellcrypt Classified 2
Protection Profile Protection Profile for Application Software Version 1.2 [App] and Extended
Package for Voice and Video over IP VVoIP Version 1.0 [VVoIP]
Security Target Cellcrypt Classified 2 Security Target Version 1.1
Evaluation
Technical Report
VID10929 Assurance Activity Report, version 1.2
CC Version Version 3.1, Revision 4
Conformance Result CC Part 2 Extended and CC Part 3 Extended
Sponsor Cellcrypt Inc.
Developer Cellcrypt Inc.
Common Criteria
Testing Lab (CCTL)
Acumen Security, LLC
CCEVS Validators Jim Donndelinger
Ken Elliott
Ken Stutterheim
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3 Architectural Information
The Target of Evaluation (TOE) is the Cellcrypt Classified 2 version 2.10.0 smartphone application, which
will run on an Android 7 based platform. The Cellcrypt Classified 2 application is a software
cryptographic application for smartphones, which enables users to have secure voice calls on an end-to-
end encrypted session.
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4 Security Policy
The logical scope of the TOE comprises:
 Authenticated connection set-up with a SIP server
 End-to-end encryption used by the TOE when encrypting/decrypting secure voice traffic
The TOE utilizes X.509 Certificates to provide a mutual authentication for the trusted channel with the
SIP server. The validity of the X.509 certificates is checked by querying a CRL. The TOE uses the TLSv1.2
protocol to protect all communications with the SIP server from modification and disclosure. In addition
to the X.509 Certificate authentication, the TOE authenticates to the SIP server using a password as an
additional layer of security. The TOE does not store the password and requires the user to enter the
password whenever the TOE requires it.
The TOE achieves end-to-end encryption using SDES-SRTP trusted channel. The keys for the SDES-SRTP
trusted channel are protected by the TLS/SIP channel while the keys are being established.
The TOE mitigates side channel attacks by utilizing a fixed rate vocoder. This prevents an attacker from
inferring information about the audio based on the bitrate being transmitted. The TOE also enables ASLR
and stack-based overflow protections.
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5 Assumptions, Threats & Clarification of Scope
5.1 Assumptions
The specific conditions listed in the following subsections are assumed to exist in the TOE’s
environment. These assumptions include both practical realities in the development of the TOE security
requirements and the essential environmental conditions on the use of the TOE.
Table 2 – Assumptions
Assumption Description
A.PLATFORM The TOE relies upon a trustworthy computing platform for its execution. This
includes the underlying platform and whatever runtime environment it provides
to the TOE.
A.PROPER_USER The user of the application software is not willfully negligent or hostile, and uses
the software in compliance with the applied enterprise security policy.
A.PROPER_ADMIN The administrator of the application software is not careless, willfully negligent
or hostile, and administers the software within compliance of the applied
enterprise security policy.
5.2 Threats
The following table lists the threats addressed by the TOE and the IT Environment. The assumed level of
expertise of the attacker for all the threats identified below is Enhanced-Basic.
Table 3 - Threats
Threat Description
T.NETWORK_ACCESS An attacker is positioned on a communications channel or
elsewhere on the network infrastructure. Attackers may
engage in communications with the application software or
alter communications between the application software and
other endpoints in order to compromise it.
T.NETWORK_EAVSDROP An attacker is positioned on a communications channel or
elsewhere on the network infrastructure. Attackers may
monitor and gain access to data exchanged between the
application and other endpoints.
T.LOCAL_ATTACK An attacker can act through unprivileged software on the
same computing platform on which the application executes.
Attackers may provide maliciously formatted input to the
application in the form of files or other local communications.
T.PHYSICAL_ACCESS An attacker may try to access sensitive data at rest.
T.UNDETECTED_TRANSMISSION An attacker may cause the TOE to exfiltrate audio and/or
video media over a remote channel while in a state where the
user has a reasonable expectation that no media is being
transmitted.
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Threat Description
T.CLOCK_DESYNC An attacker may cause the TOE to use incorrect clock data,
resulting in a denial of service from causing encryption
and/or authentication connection failures.
T.MEDIA_DISCLOSURE An attacker can use the encrypted variable rate vocoder
frames to their advantage to decode transmitted data.
5.3 Clarification of Scope
All evaluations (and all products) have limitations, as well as potential misconceptions that need
clarifying. This text covers some of the more important limitations and clarifications of this evaluation.
Note that:
 As with any evaluation, this evaluation only shows that the evaluated configuration meets the
security claims made, with a certain level of assurance. The level of assurance for this evaluation
is defined within the Protection Profile for Application Software Version 1.2 [App] and Extended
Package for Voice and Video over IP VVoIP Version 1.0 [VVoIP].
 Consistent with the expectations of the Protection Profile, this evaluation did not specifically
search for, nor seriously attempt to counter, vulnerabilities that were not “obvious” or
vulnerabilities to objectives not claimed in the ST. The CEM defines an “obvious” vulnerability as
one that is easily exploited with a minimum of understanding of the TOE, technical
sophistication and resources.
 The evaluation of security functionality of the product was limited to the functionality specified
in the claimed PP and applicable Technical Decisions. Any additional security related functional
capabilities that may be included in the product were not covered by this evaluation.
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6 Documentation
The following documents were provided by the vendor with the TOE for evaluation:
 Cellcrypt Classified 2 Security Target, Version 1.1 [ST]
 Administrative Guidance Document - Cellcrypt Classified 2, version 1.2 [AGD]
Any additional customer documentation provided with the product, or that is available online was not
included in the scope of the evaluation and therefore should not to be relied upon when configuring or
operating the device as evaluated.
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7 TOE Evaluated Configuration
7.1 Evaluated Configuration
The Target of Evaluation (TOE) is the Cellcrypt Classified version 2.10.0 smartphone application, which
will run on an Android 7 based platform. The Cellcrypt Classified version 2.10.0 application is a software
cryptographic application for smartphones, which enables users to have secure voice calls on an end-to-
end encrypted session.
The logical scope of the TOE comprises:
 Authenticated connection set-up with a SIP server
 End-to-end encryption used by the TOE when encrypting/decrypting secure voice traffic
The TOE utilizes X.509 Certificates to provide a mutual authentication for the trusted channel with the
SIP server. The validity of the X.509 certificates is checked by querying a CRL. The TOE uses the TLSv1.2
protocol to protect all communications with the SIP server from modification and disclosure. In addition
to the X.509 Certificate authentication, the TOE authenticates to the SIP server using a password as an
additional layer of security. The TOE does not store the password and requires the user to enter the
password whenever the TOE requires it.
The TOE achieves end-to-end encryption using SDES-SRTP trusted channel. The keys for the SDES-SRTP
trusted channel are protected by the TLS/SIP channel while the keys are being established.
The TOE mitigates side channel attacks by utilizing a fixed rate vocoder. This prevents an attacker from
inferring information about the audio based on the bitrate being transmitted. The TOE also enables ASLR
and stack-based overflow protections.
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8 IT Product Testing
This section describes the testing efforts of the developer and the evaluation team. It is derived from
information contained in Evaluation Test Report for the Cellcrypt Classified 2, which is not publicly
available. The Assurance Activities Report provides an overview of testing and the prescribed assurance
activities.
8.1 Developer Testing
No evidence of developer testing is required in the Assurance Activities for this product.
8.2 Evaluation Team Independent Testing
The evaluation team verified the product according the vendor-provided guidance documentation and
ran the tests specified in the Protection Profile for Application Software Version 1.2 [App] and Extended
Package for Voice and Video over IP VVoIP Version 1.0 [VVoIP]. The Independent Testing activity is
documented in the Assurance Activities Report, which is publicly available, and is not duplicated here.
Multiple test beds were constructed to exercise Application Software capabilities and claimed security
functionality. The following tooling was used as part of the test activities,
 Android Studio
 GHIDRA
 JADX
 Nmap
 Wireshark
 Peer VoIP Endpoint
 Acumen TLS
 ESC (OpenSSL/OpenSIPS)
 CRL server
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9 Results of the Evaluation
The results of the assurance requirements are generally described in this section and are presented in
detail in the proprietary documents: the Detailed Test Report (DTR) and the Evaluation Technical Report
(ETR) and as summarized in the Cellcrypt Classified 2 Assurance Activity Report, Version 1.2. The reader
of this document can assume that activities and work units received a passing verdict.
A verdict for an assurance component is determined by the resulting verdicts assigned to the
corresponding evaluator action elements. The evaluation was conducted based upon CC version 3.1 rev
4 and CEM version 3.1 rev 4. The evaluation determined the Cellcrypt Classified 2 to be Part 2 extended,
and meets the SARs contained in the PP. Additionally the evaluator performed the Assurance Activities
specified in the [App] and [VVoIP].
9.1 Evaluation of Security Target
The evaluation team applied each ASE CEM work unit. The ST evaluation ensured the ST contains a
description of the environment in terms of policies and assumptions, a statement of security
requirements claimed to be met by the Cellcrypt Classified 2 that are consistent with the Common
Criteria, and product security function descriptions that support the requirements. Additionally, the
evaluator performed an assessment of the Assurance Activities specified in the Protection Profile for
Application Software Version 1.2 [App] and Extended Package for Voice and Video over IP VVoIP
Version 1.0 [VVoIP].
The validators reviewed the work of the evaluation team and found that sufficient evidence and
justification was provided by the evaluation team to confirm that the evaluation was conducted in
accordance with the requirements of the CEM, and that the conclusion reached by the evaluation team
was justified.
9.2 Evaluation of Development Documentation
The evaluation team assessed the design documentation and found it adequate to aid in understanding
how the TSF provides the security functions. The design documentation consists of a functional
specification contained in the Security Target's TOE Summary Specification. Additionally, the evaluator
performed the Assurance Activities specified in the [App] and [VVoIP] related to the examination of the
information contained in the TOE Summary Specification.
The validators reviewed the work of the evaluation team and found that sufficient evidence and
justification was provided by the evaluation team to confirm that the evaluation was conducted in
accordance with the Assurance Activities, and that the conclusion reached by the evaluation team was
justified.
9.3 Evaluation of Guidance Documents
The evaluation team ensured the adequacy of the user guidance in describing how to use the
operational TOE. Additionally, the evaluation team ensured the adequacy of the administrator guidance
in describing how to securely administer the TOE. The guides were assessed during the design and
testing phases of the evaluation to ensure they were complete. Additionally, the evaluator performed
the Assurance Activities specified in the [App] and [VVoIP] related to the examination of the information
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contained in the operational guidance documents.
The validators reviewed the work of the evaluation team and found that sufficient evidence and
justification was provided by the evaluation team to confirm that the evaluation was
conducted in accordance with the Assurance Activities, and that the conclusion reached by
the evaluation team was justified.
9.4 Evaluation of Life Cycle Support Activities
The evaluation team found that the TOE was identified. Additionally, the team verified that both the
TOE and its supporting documentation are consistently reference the same version and use the same
nomenclature. The evaluation team also verified that the vendor website identified the TOE version
accurately.
The validators reviewed the work of the evaluation team and found that sufficient evidence and
justification was provided by the evaluation team to confirm that the evaluation was conducted in
accordance with the requirements of the CEM, and that the conclusion reached by the evaluation team
was justified.
9.5 Evaluation of Test Documentation and the Test Activity
The evaluation team ran the set of tests specified by the Assurance Activities in the [App] and [VVoIP]
and recorded the results in a Test Report, summarized in the Evaluation Technical Report and Assurance
Activities Report.
The validators reviewed the work of the evaluation team and found that sufficient evidence was
provided by the evaluation team to show that the evaluation activities addressed the test activities in
the [App] and [VVoIP], and that the conclusion reached by the evaluation team was justified.
9.6 Vulnerability Assessment Activity
The evaluation team performed a public search for vulnerabilities on March 22, 2019 and did not
discover any issues with the TOE. The following sources of public vulnerability information were
searched:
 https://www.cvedetails.com/
The search terms used included:
 Cellcrypt
 OpenSSL 2.0.10
 PJSIP 2.1
 libSRTP v1.5.4
The evaluation team also performed a general Google search for “cellcrypt vulnerabilities” on April 12,
2019 and did not discover any vulnerabilities.
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The validators reviewed the work of the evaluation team and found that sufficient evidence and
justification was provided by the evaluation team to confirm that the evaluation addressed the
vulnerability analysis Assurance Activities in the [App] and [VVoIP], and that the conclusion reached by
the evaluation team was justified.
9.7 Summary of Evaluation Results
The evaluation team's assessment of the evaluation evidence demonstrates that the claims in
the ST are met. Additionally, the evaluation team's test activities also demonstrated the
accuracy of the claims in the ST.
The validation team's assessment of the evidence provided by the evaluation team is that it
demonstrates that the evaluation team performed the Assurance Activities in the [App] and [VVoIP], and
correctly verified that the product meets the claims in the ST.
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10 Validator Comments & Recommendations
The Validation Team has no additional comments or recommendations.
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11 Annexes
Not applicable.
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12 Security Target
Please see the Cellcrypt Classified 2 Security Target, Version 1.1 [ST].
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13 Glossary
The following definitions are used throughout this document:
 Common Criteria Testing Laboratory (CCTL). An IT security evaluation facility accredited by the
National Voluntary Laboratory Accreditation Program (NVLAP) and approved by the CCEVS
Validation Body to conduct Common Criteria-based evaluations.
 Conformance. The ability to demonstrate in an unambiguous way that a given implementation
is correct with respect to the formal model.
 Evaluation. The assessment of an IT product against the Common Criteria using the Common
Criteria Evaluation Methodology to determine whether or not the claims made are justified; or
the assessment of a protection profile against the Common Criteria using the Common
Evaluation Methodology to determine if the Profile is complete, consistent, technically sound
and hence suitable for use as a statement of requirements for one or more TOEs that may be
evaluated.
 Evaluation Evidence. Any tangible resource (information) required from the sponsor or
developer by the evaluator to perform one or more evaluation activities.
 Feature. Part of a product that is either included with the product or can be ordered separately.
 Target of Evaluation (TOE). A group of IT products configured as an IT system, or an IT product,
and associated documentation that is the subject of a security evaluation under the CC.
 Validation. The process carried out by the CCEVS Validation Body leading to the issue of a
Common Criteria certificate.
 Validation Body. A governmental organization responsible for carrying out validation and for
overseeing the day-to-day operation of the NIAP Common Criteria Evaluation and Validation
Scheme.
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14 Bibliography
The Validation Team used the following documents to produce this Validation Report:
1. Common Criteria for Information Technology Security Evaluation - Part 1: Introduction and
general model, Version 3.1 Revision 4.
2. Common Criteria for Information Technology Security Evaluation - Part 2: Security functional
requirements, Version 3.1 Revision 4.
3. Common Criteria for Information Technology Security Evaluation - Part 3: Security assurance
requirements, Version 3.1 Revision 4.
4. Common Evaluation Methodology for Information Technology Security Evaluation, Version 3.1
Revision 4.
5. Cellcrypt Classified 2 Security Target, Version 1.1 [ST]
6. Administrative Guidance Document - Cellcrypt Classified 2, version 1.2 [AGD]
7. Protection Profile for Application Software Version 1.2 [App]
8. Extended Package for Voice and Video over IP VVoIP Version 1.0 [VVoIP]
9. Cellcrypt Classified 2 Assurance Activity Report