ETSI TS 103 457 V1.1.1 (2018-10)

ETSI TS 103 457 V1.1.1 (2018-10)






TECHNICAL SPECIFICATION
CYBER;
Trusted Cross-Domain Interface:
Interface to offload sensitive functions to a trusted domain

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2 ETSI TS 103 457 V1.1.1 (2018-10)



Reference
DTS/CYBER-0019
Keywords
cybersecurity, interface
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3 ETSI TS 103 457 V1.1.1 (2018-10)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Definition of terms and abbreviations . 7
3.1 Terms . 7
3.2 Abbreviations . 8
4 General . 8
4.1 TCDI functional requirements . 8
4.2 TCDI life cycle . 9
4.2.1 Life cycle Diagram . 9
4.2.2 Connection between LTD and MTD . 9
4.2.3 Session . 10
4.2.4 Keep the trusted connection between the LTD and the MTD . 10
4.2.5 Releasing and erasing . 11
5 Interface Elementary Functions . 12
5.1 General provisions . 12
5.2 Connection and session management . 12
5.2.1 General . 12
5.2.2 TD_OpenConnection . 13
5.2.3 TD_CloseConnection. 13
5.2.4 TD_CreateSession . 13
5.2.5 TD_CloseSession . 14
5.2.6 TD_TrustRenewal . 14
5.3 Data and value management . 15
5.3.1 TD_CreateObject . 15
5.3.2 TD_GetObjectValue . 15
5.3.3 TD_PutObjectValue. 16
5.4 Transferring cryptographic functionality . 16
5.4.1 Entropy request . 16
5.4.1.1 General . 16
5.4.1.2 TD_GetRandom . 17
5.4.2 Encryption keys request . 17
5.4.2.1 General . 17
5.4.2.2 TD_GenerateEncryptionKey . 17
5.4.3 Trusted timestamping . 18
5.4.3.1 General . 18
5.4.3.2 TD_GetTrustedTimestamping . 18
5.4.4 Secure archive . 18
5.4.4.1 General . 18
5.4.4.2 TD_CreateArchive . 19
5.4.4.3 TD_Archive . 19
5.4.4.4 TD_CloseArchive . 20
5.4.5 Secure storage . 20
5.4.5.1 General . 20
5.4.5.2 TD_CreateStorage . 20
5.4.5.3 TD_DeleteStorage . 21
5.4.5.4 TD_StoreData . 21
5.4.5.5 TD_GetStorageValue . 22
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5.6 Search capabilities . 22
5.6.1 Container search . 22
5.6.1.1 General . 22
5.6.1.2 TD_GetStorage . 23
5.6.1.3 TD_Search . 23
6 Encoding . 24
6.1 Message identifiers . 24
6.2 Type (TTLV) codes . 25
6.3 Tag (TTLV) codes . 25
6.4 Status Codes . 26
Annex A (informative): Use Cases . 28
A.1 Entropy request scenario . 28
A.1.1 Description . 28
A.1.2 Example . 28
A.2 Encrypted Virtual Machine use case (including LTD execution environment check) . 29
A.2.1 Description . 29
A.2.2 Example . 30
A.2.2.1 Introduction. 30
A.2.2.2 Successful case . 30
A.2.2.3 Failure case . 30
A.3 Secure archive use case . 30
A.3.1 Description . 30
A.3.2 Example . 31
A.4 Secure query use case . 32
A.4.1 Description . 32
A.4.2 Example . 33
A.5 Secure Storage use case . 33
A.5.1 Description . 33
A.5.2 Example . 34
A.6 Authentication use case . 35
A.6.1 Description . 35
A.6.2 Example . 35
A.7 Lawful intercept use case . 36
A.7.1 Description . 36
A.7.2 Example . 36
A.8 NFV sec use case . 37
A.8.1 Description . 37
A.8.2 Example . 38
Annex B (informative): Guidelines . 39
B.1 Implementation guidelines . 39
B.1.1 Global architecture . 39
B.1.2 Connection management . 39
B.1.3 Predefined Container-id and Object-id . 39
B.2 Good practice . 39
B.3 TTLV encoding examples . 40
B.3.1 GetRandom. 40
B.3.2 StoreData . 40
Annex C (informative): Bibliography . 41
History . 42

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5 ETSI TS 103 457 V1.1.1 (2018-10)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Cyber Security (CYBER).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Deploying hosted sensitive functions in modern virtualized IT infrastructure is still a concern and a major issue.
The main threats are malicious administrators operating the IT infrastructure including: network, storage and host
platform facilities and virtualization management. These threats and related issues are thoroughly discussed in ETSI
TR 103 308 [i.1].
ETSI specification group NFV SEC is in charge of defining a secured standard architecture. Proprietary solutions
providing trusted security for virtualized environments have started emerging.
These new envisioned architectures add security components at the hosting platform level and into centralized services
in charge of security management. The key concept is Hardware Root of Trust to get strong guarantees on the integrity
of the deployed elements. These architectures offer secured managed infrastructures that enable deployment, live
migration of encrypted VMs.
In addition to these works, the present document proposes a new interoperable interface that should help building
sensitive services with trust.
This interface applies in the setting where two trust domains (see ETSI GS NFV-SEC 013 [i.4] for details) are defined:
• The More Trusted Domain (MTD) contains resources (network, storage, processing) where sensitive functions
can be offloaded.
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6 ETSI TS 103 457 V1.1.1 (2018-10)
• The Less Trusted Domain (LTD) contains resources that can be managed without the risk of compromising
sensitive information, since these functionalities are offloaded to the MTD.
This Trusted Cross-Domain interface includes a set of basic functions called by the LTD entity but performed securely
within the MTD. This set of basic functions enables the LTD entity to build more complex services.

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7 ETSI TS 103 457 V1.1.1 (2018-10)
1 Scope
The present document specifies a high-level service-oriented interface, as an application layer with a set of mandatory
functions, to access secured services provided by, and executed in a More Trusted Domain. The transport layer is out of
scope and left to the architecture implementation.
This interface is not considered as a replacement of the already existing technologies (such as PKCS#11, KMIP, etc.)
but rather operating on top of these.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long-term validity.
Not applicable.
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long-term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TR 103 308: "CYBER; Security baseline regarding LI and RD for NFV and related
platforms".
[i.2] ETSI GR NFV-SEC 011: "Network Functions Virtualisation (NFV); Security; Report on NFV LI
Architecture".
[i.3] Wikipedia definition of Type-Length-Value.
[i.4] ETSI GS NFV-SEC 013: "Network Functions Virtualisation (NFV) Release 3; Security ; Security
Management and Monitoring specification".
3 Definition of terms and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:
domain: set of domain services
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trusted cross domain interface: domain service with a set of dedicated domain interface functions for communication
between domain services of different domains (inter-domain communication)
trusted cross domain interface function: function of a domain interface which is implemented by a domain service of
another domain in order to realize inter-domain communication
trusted cross domain object: data generated by a domain service
trusted cross domain service: service with a set of dedicated domain service functions for communication with other
domain services of the same domain (intra-domain communication)
trusted cross domain service function: function of a domain service which is implemented by the same or another
domain service in order to realize intra-domain communication
trusted cross secured domain interface: domain interface offering access to secured domain services
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Access Control
AES Advanced Encryption Standard
CN Common Name
FW FireWall
HSM Hardware Security Module
IT Information Technology
KMIP Key Management Interoperability Protocol
LI Lawful Interception
LTD Less Trusted Domain
MF Mediation Function
MTD More Trusted Domain
NFV Network Function Virtualization
PNRG Pseudorandom Number Generator
RNG Random Number Generator
RSA Rivest-Shamir-Adleman
SEC Security
TCDI Trusted Cross-Domain Interface
TCF Triggering Control Function
TCO Trusted COntext
TLS Transport Layer Security
TPM Trusted Platform Module
TTLV Tag-Type-Length-Value encoding
VM Virtual Machine
VMM Virtual Machine Manager
vPOI virtual Point Of Interception
4 General
4.1 TCDI functional requirements
TCDI provides services to the application layer. MTD implements, exposes and delivers the required services.
TCDI provides the following high-level services:
• Key Management: TCDI allows symmetric and asymmetric keys to be requested and received.
• Cryptographic operations: TCDI allows basic cryptographic operation to be performed in the MTD.
EXAMPLE: Random number generator.
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• File/Database/Storage access: TCDI provides services to append, push and store sensitive data in containers
such as files or database.
TCDI shall allow the use of sensitive objects in several functions without regeneration and compromise.
TCDI shall allow the sharing of MTD domain objects by LTD entities.
A LTD entity shall provide attestations on demand to the MTD, and the MTD shall verify those attestations to ensure
the trust relation between the domains.
TCDI shall allow cascading the execution of domain service functions of the LTD on domain objects of the MTD
within a single session.
4.2 TCDI life cycle
4.2.1 Life cycle Diagram
The interface allows a LTD entity to establish a trusted connection to a server in the MTD to execute sensitive
operations and compose results within a TCO guaranteed by the MTD server (illustrated in figure 1). Only one
connection per LTD entity shall be accepted.

Figure 1: Interface Life Cycle
4.2.2 Connection between LTD and MTD
The use of TCDI is initiated by one LTD with the establishment of a connection to one MTD service. The MTD may
close the connection after some period of inactivity (see Good Practice section for recommendations).
The MTD shall support two modes of operation depending on the LTD trust level:
• Trusted mode enables the MTD to verify that the LTD is running in an authorized environment (see Good
Practice section for recommendations).
• Untrusted hardware mode enables the use of TCDI when the LTD does not have access to a TPM.
The MTD shall have a database of authorized RSA key pairs and the LTD shall be able to sign data as a TPM would.
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MTD is responsible for granting the appropriate level of services available to a LTD connection depending on the trust
level and the requested LTD-Role. MTD shall deny connections if the requested LTD-Role does not match the trust
level.
MTD shall accept only one connection per LTD, and simultaneous connections from multiple LTD. New connections to
the MTD shall get rejected if the supported limit of simultaneous connections is reached.
4.2.3 Session
A session describes a set of transactions between the LTD and MTD for
...