ETSI TR 135 934 V17.0.0 (2022-04)

Universal Mobile Telecommunications System (UMTS); LTE; Specification of the TUAK algorithm set: A second example algorithm set for the 3GPP authentication and key generation functions f1, f1*, f2, f3, f4, f5 and f5*; Document 4: Report on the design and evaluation (3GPP TR 35.934 version 17.0.0 Release 17)

RTR/TSGS-0335934vh00

General Information

• Status: Not Published
• Technical Committee: 3GPP SA 3 - Security
• Current Stage: 12 - Completion
• Completion Date: 07-Apr-2022

Standards Content (Sample)

ETSI TR 135 934 V17.0.0 (2022-04)






TECHNICAL REPORT
Universal Mobile Telecommunications System (UMTS);
LTE;
Specification of the TUAK algorithm set: A second example
algorithm set for the 3GPP authentication and key generation
functions f1, f1*, f2, f3, f4, f5 and f5*;
Document 4: Report on the design and evaluation
(3GPP TR 35.934 version 17.0.0 Release 17)

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3GPP TR 35.934 version 17.0.0 Release 17 1 ETSI TR 135 934 V17.0.0 (2022-04)

Reference
RTR/TSGS-0335934vh00
Keywords
LTE,SECURITY,UMTS
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Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 6
2 References . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 7
4 Structure of this report . 8
5 Background to the design and evaluation work . 8
6 Summary of algorithm requirements . 9
6.0 Introduction . 9
6.1 General requirements for 3GPP cryptographic functions and algorithms (as stated for MILENAGE) . 9
6.2 Authentication and key agreement functions (as stated for MILENAGE) . 9
6.2.0 Introduction. 9
6.2.1 Implementation and operational considerations . 10
6.2.2 Type of algorithm . 10
6.2.2.1 f1 . 10
6.2.2.2 f1* . 10
6.2.2.3 f2 . 10
6.2.2.4 f3 . 10
6.2.2.5 f4 . 10
6.2.2.6 f5 . 11
6.2.2.7 f5* . 11
6.3 Tuak-specific requirements . 11
6.3.1 Difference from MILENAGE . 11
6.3.2 256-bit key support . 11
6.3.3 Operator customization . 11
6.3.4 Implementation and operational considerations . 12
7 Overview of the Tuak design . 12
8 Design rationale . 13
8.0 Introduction . 13
8.1 Brand new design, or design based on an existing public algorithm? . 13
8.2 Block cipher, stream cipher, MAC or hash function? . 13
8.3 Which hash function? . 13
8.4 What sort of Keccak function to use . 14
8.5 Keccak parameter selection . 14
8.6 Security evaluation of Keccak . 15
8.6.0 Introduction. 15
8.6.1 What about the internet stories about NIST weakening SHA-3? . 15
8.7 A note on IPR . 16
8.7.1 Keccak IPR . 16
8.7.2 Tuak IPR . 16
8.8 Padding bits . 16
8.9 Flexible input and output sizes . 16
8.10 Operator customization . 16
9 Independent security and performance evaluation . 17
9.0 Introduction . 17
9.1 Independent security evaluation . 17
9.2 Independent SIM card performance evaluation . 17
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3GPP TR 35.934 version 17.0.0 Release 17 4 ETSI TR 135 934 V17.0.0 (2022-04)
10 More notes on implementation and side channel attacks . 18
10.1 Protecting implementations against side channel attacks . 18
10.2 Software implementation and the NIST SHA-3 standard . 18
11 Conclusions . 18
Annex A: Change history . 19
History . 20

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3GPP TR 35.934 version 17.0.0 Release 17 5 ETSI TR 135 934 V17.0.0 (2022-04)
Foreword
rd
This Technical Report has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
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1 Scope
The present document (together with three accompanying documents, [8], [9] and [10] describes the design rationale,
and presents evaluation results, on the Tuak algorithm set [5] – a second example set of algorithms which may be used
as the authentication and key generation functions f1, f1*, f2, f3, f4, f5 and f5*, e.g. as an alternative to MILENAGE.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or non-
specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TS 33.102: "3G Security; Security Architecture", (available at
http://www.3gpp.org/ftp/specs/html-info/33102.htm).
[3] 3G TS 33.105 (V 3.4.0) (2000-07): "3G Security; Cryptographic Algorithm Requirements
(Release 1999)".
[4] 3GPP TS 35.206: "3G Security; Specification of the MILENAGE algorithm set: An example
algorithm set for the 3GPP authentication and key generation functions f1, f1*, f2, f3, f4, f5 and
f5*; Document 2: Algorithm specification", (available at http://www.3gpp.org/ftp/Specs/html-
info/35206.htm).
[5] 3GPP TS 35.231: "3G Security; Specification of the Tuak algorithm set: A second example
algorithm set for the 3GPP authentication and key generation functions f1, f1*, f2, f3, f4, f5 and
f5*; Document 1: Algorithm specification", (available at http://www.3gpp.org/ftp/Specs/html-
info/35231.htm).
[6] 3GPP TS 35.232: "3G Security; Specification of the Tuak algorithm set: A second example
algorithm set for the 3GPP authentication and key generation functions f1, f1*, f2, f3, f4, f5 and
f5*; Document 2: Implementers' Test Data", (available at http://www.3gpp.org/ftp/Specs/html-
info/35232.htm).
[7] 3GPP TS 35.233: "3G Security; Specification of the Tuak algorithm set: A second example
algorithm set for the 3GPP authentication and key generation functions f1, f1*, f2, f3, f4, f5 and
f5*; Document 3: Design Conformance Test Data", (available at
http://www.3gpp.org/ftp/Specs/html-info/35233.htm).
[8] "Security Assessment of Tuak Algorithm Set", Guang Gong, Kalikinkar Mandal, Yin Tan and
Teng Wu, included as an accompanying document to the present report (available at
http://www.3gpp.org/ftp/Specs/archive/35_series/35.935/SAGE_report/Secassesment.zip).
[9] "Performance Evaluation of the Tuak algorithm in support of the ETSI SAGE standardisation
group", Keith Mayes, included as an accompanying document to the present report (available at
http://www.3gpp.org/ftp/Specs/archive/35_series/35.936/SAGE_report/Perfevaluation.zip).
[10] "Performance Evaluation of the Tuak algorithm in support of the ETSI SAGE standardisation
group – extension report", Keith Mayes, included as an accompanying document to the present
report (available at
http://www.3gpp.org/ftp/Specs/archive/35_series/35.936/SAGE_report/Perfevaluationext.zip).
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[11] "Note on side-channel attacks and their countermeasures", G. Bertoni, J. Daemen, M. Peeters, G.
van Assche (available at http://keccak.noekeon.org/NoteSideChannelAttacks.pdf).
[12] "Building power analysis resistant implementations of Keccak", G. Bertoni, J. Daemen, M.
Peeters, G. van Assche (available at http://csrc.nist.gov/groups/ST/hash/sha-
3/Round2/Aug2010/documents/papers/BERTONI_KeccakAntiDPA.pdf).
[13] Wassenaar Arrangement on Export Controls for Conventional Arms and Dual-Use Goods and
Technologies, http://www.wassenaar.org.
[14] "Announcing Draft Federal Information Processing Standard (FIPS) 202, SHA-3 Standard:
Permutation-Based Hash and Extendable-Output Functions, and Draft Revision of the
Applicability Clause of FIPS 180-4, Secure Hash Standard, and Request for Comments", NIST,
th
28 May 2014, available at https://www.federalregister.gov/articles/2014/05/28/2014-
12336/announcing-draft-federal-information-processing-standard-fips-202-sha-3-standard-
permutation-based.
[15] "Early Symmetric Crypto (ESC) seminar 2013" (available at
https://www.cryptolux.org/mediawiki-esc2013/index.php/ESC_2013 )
[16] "The KECCAK sponge function family" (available at http://www.noekeon.org)
[17] https://www.cdt.org/blogs/joseph-lorenzo-hall/2409-nist-sha-3
[18] http://yro.slashdot.org/story/13/09/28/0219235/did-nist-cripple-sha-3
[19] https://www.schneier.com/blog/archives/2013/10/will_keccak_sha-3.html
[20] http://keccak.noekeon.org/yes_this_is_keccak.html
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 21.905 [1] and the following apply. A
term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 [1].
Keccak: algorithm selected as the winner of the SHA-3 competition
MILENAGE: previously designed example algorithm set for the 3GPP Authentication and Key Generation Functions
TOP : value derived from TOP and K and used within the computations of the functions f1, f1*, f2, f3, f4, f5 and f5*
C
Tuak: newly designed example algorithm set for the 3GPP Authentication and Key Generation Functions. It should be
pronounced like "too-ack"
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in TR 21.905 [1] and the following apply. An
abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in
TR 21.905 [1].
AES Advanced Encryption Standard block cipher
AK Anonymity Key
AMF Algorithm Management Field
AuC Authentication Centre
CK Cipher Key
CPU Central Processing Unit
DEMA Differential Electromagnetic Analysis
DPA Differential Power Analysis
IC Integrated Circuit
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IK Integrity Key
K Long lived subscriber unique key
MAC Message Authentication Code
MAC-A MAC for normal authentication vectors
MAC-S MAC for resynchronization vectors
MULTOS Multi-application smart card operating system
NIST National Institute of Standards and Technology
NSA National Security Agency
NVM Non-Volatile Memory
RAM Random Access Memory
RAND Random input parameter to authentication and key generation functions
RES Response value
RNC Radio Network Controller
ROM Read-Only Memory
SAGE Security Algorithms Group of Experts
NOTE: This is an ETSI Technical Committee.
SHA-2 Secure Hash Algorithm already standardized by NIST
SHA-3 Secure Hash Algorithm soon to be standardized by NIST
TOP Tuak Operator Variant Algorithm Configuration Field
SEMA Simple Electromagnetic Analysis
SIM Subscriber Identity Module
SPA Simple Power Analysis
SQN Sequence Number
UICC Universal Integrated Circuit Card
USIM Universal Subscriber Identity Module
XMAC Expected MAC value
4 Structure of this report
The main content of the present document is organized as follows:
- Clause 5 and 6 give the requirements and background that were considered during the design of Tuak – first
recalling the functional and performance requirements that were used for MILENAGE, then noting some
differences and additional points that apply for Tuak.
- Clause 7 gives a brief overview of the Tuak design.
- Clause 8 runs through choices made during the design of Tuak, and the reasons behind those choices.
- Clause 9 introduces independent assessments that have been carried out on the security and performance of
Tuak. The full independent assessment reports are included as companion documents to this one.
- Clause 10 gives some further observations on software implementation and protection against side channel
attacks.
- Clause 11 concludes with an overall assessment of Tuak's fitness for purpose.
Three further documents [8], [9] and [10] complete the present document, as explained in clause 9.
5 Background to the design and evaluation work
rd
The 3 Generation Partnership Project (3GPP) is a global initiative dedicated to the development of specifications for
the next generations of cellular mobile systems. Integration of strong security services is an important feature of this
system and the general security architecture is defined in ref. [2]. The implementation of these security services should
be based on a variety of cryptographic functions/algorithms.
Out of the full algorithm suite, only the UMTS encryption algorithms (f8) and the UMTS integrity algorithms (f9) are
fully standardized. f0 represents a random number generation algorithm, and has no standardization or interoperability
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requirements at all. The remaining cryptographic functions for authentication and key agreement (f1 – f5*) are allocated
to the Authentication Centre (AuC) and the USIM; this means that the functions are proprietary to the home
environment, and there is no need for formal standardization of these algorithms. However, there are good reasons to
have a well trusted example set of functions available for this purpose, for use by operators that choose not to develop
their own solutions. The MILENAGE algorithm set [4] was created to meet this need.
There are also good reasons to have a second trusted example set of (f1 – f5*) algorithms available:
- To have a fallback already in place in case MILENAGE is ever compromised.
- In particular, for the embedded UICC, where it may be sensible to have two strong algorithms installed on the
platform and available for selection by subsequently loaded USIM applications. This provides choice to
operators; it also provides resilience against future cryptanalysis of either algorithm, in devices that may have a
long lifetime in the field.
The Tuak algorithm set [5], [6] and [7] has been created to serve as this second trusted example algorithm set.
6 Summary of algorithm requirements
6.0 Introduction
When MILENAGE was created, the requirements specification was taken from [3]. Clauses 6.1 and 6.2 below
reproduce the main requirements necessary to understand the present document. Clause 6.3 describes some new
requirements that came into play when designing Tuak.
6.1 General requirements for 3GPP cryptographic functions and
algorithms (as stated for MILENAGE)
The functions should be designed with a view to their continued use for a period of at least 20 years. Successful attacks
with a workload significantly less than exhaustive key search through the effective key space should be impossible.
The designers of above functions should design algorithms to a strength that reflects the above qualitative requirements.
Legal restrictions on the use or export of equipment containing cryptographic functions may prevent the use of such
equipment in certain countries.
It is the intention that UE and USIMs that embody such algorithms should be free from restrictions on export or use, in
order to allow the free circulation of 3G terminals. Network equipment, including RNC and AuC, may be expected to
come under more stringent restrictions. It is the intention that RNC and AuC that embody such algorithms should be
exportable under the conditions of the Wassenaar Arrangement, see reference [13].
6.2 Authentication and key agreement functions (as stated for
MILENAGE)
6.2.0 Introduction
The mechanisms for authentication and key agreement described in clause 6.3 of [2] require the following
cryptographic functions:
f1  The network authentication function;
f1*  The re-synchronization message authentication function;
f2  The user authentication function;
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f3  The cipher key derivation function;
f4  The integrity key derivation function;
f5  The anonymity key derivation function;
f5*  The anonymity key derivation function for re-synchronization.
6.2.1 Implementation and operational considerations
The functions f1–f5* should be designed so that they can be implemented on an IC card equipped with an 8-bit
microprocessor running at 3,25 MHz with 8 kbyte ROM and 300 byte RAM and produce AK, XMAC-A, RES, CK and
IK in less than 500 ms execution time.
6.2.2 Type of algorithm
6.2.2.1 f1
f1: the network authentication function
f1:  (K; SQN, RAND, AMF) → MAC-A
...