ISO/IEC FDIS 17825

Information technology — Security techniques — Testing methods for the mitigation of non-invasive attack classes against cryptographic modules

Techonologie de l'information — Techniques de sécurité — Methodes de test pour la protection contre les attaques non intrusives des modules cryptographiques

General Information

• Status: Not Published
• ICS: 35.030 - IT Security
• Technical Committee: ISO/IEC JTC 1/SC 27 - Information security, cybersecurity and privacy protection
• Drafting Committee: ISO/IEC JTC 1/SC 27 - Information security, cybersecurity and privacy protection
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 01-Sep-2023
• Completion Date: 01-Sep-2023

Relations

• Revises: ISO/IEC 17825:2016 - Information technology — Security techniques — Testing methods for the mitigation of non-invasive attack classes against cryptographic modules
• Effective Date: 06-Jun-2022

Standards Content (Sample)

ISO/IEC JTC 1/SC 27 NXXXX
Style Definition: Heading 1: Indent: Left: 0 pt, First
line: 0 pt, Tab stops: Not at 21.6 pt
ISO/IEC FDIS 17825:2023(E)
Style Definition: Heading 2: Font: Bold, Tab stops: Not
at 18 pt
ISO/IEC JTC1/SC 27/WG 3
Style Definition: Heading 3: Font: Bold
Date: 2023-04-0408-18
Style Definition: Heading 4: Font: Bold
Style Definition: Heading 5: Font: Bold
Secretariat: DIN
Style Definition: Heading 6: Font: Bold
Information technology — Security techniques — Testing methods for the mitigation of non-
Style Definition: ANNEX
invasive attack classes against cryptographic modules
Style Definition: AMEND Terms Heading: Font: Bold
Style Definition: AMEND Heading 1 Unnumbered:
Techonologie de l'information — Techniques de sécurité — Methodes de test pour la protection contre
Font: Bold
les attaques non intrusives des modules cryptographiques
Formatted: Font: Bold

---------------------- Page: 1 ----------------------
ISO/IEC FDIS 17825:2023(E)
© ISO/IEC 2022 2023 Formatted
Formatted: Indent: Left: 14.2 pt, Right: 14.2 pt, Space
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part
Before: 0 pt, No page break before, Adjust space
of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or
between Latin and Asian text, Adjust space between
mechanical, including photocopying, or posting on the internet or an intranet, without prior written per-
Asian text and numbers
mission. Permission can be requested from either ISO at the address below or ISO’sISO's member body
Formatted: Default Paragraph Font
in the country of the requester.
ISO copyright officeCopyright Office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Formatted: Indent: Left: 14.2 pt, First line: 0 pt, Right:
14.2 pt, Adjust space between Latin and Asian text,
Phone: + 41 22 749 01 11
Adjust space between Asian text and numbers
Email: [e-mail]
Email: [e-mail]
Website: www.iso.orgwww.iso.org
Formatted: Indent: Left: 14.2 pt, First line: 0 pt, Right:
14.2 pt, Adjust space between Latin and Asian text,
Published in Switzerland.
Adjust space between Asian text and numbers
ii © ISO/IEC 2023 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/IEC FDIS 17825:2023(E)
Contents
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 3
5 Document organization . 4
6 Non-invasive attack methods . 4
7 Non-invasive attack test methods . 7
7.1 General . 7
7.2 Test strategy . 7
7.3 Side-channel analysis workflow . 8
8 Side-channel analysis of symmetric-key cryptosystems . 13
8.1 Introduction . 13
8.2 Timing attacks . 13
8.3 SPA/SEMA . 14
8.4 DPA/DEMA . 14
9 ASCA on asymmetric cryptography . 16
9.1 Introduction . 16
9.2 Detailed side-channel resistance test framework . 17
9.3 Timing attacks . 18
9.4 SPA/SEMA . 19
9.5 DPA/DEMA . 20
Annex A (normative) Non-invasive attack mitigation pass/fail test metrics . 21
A.1 Introduction . 21
A.2 Security level 3 . 21
A.2.1 Time limit . 21
A.2.2 SPA and SEMA . 21
A.2.3 DPA and DEMA . 21
A.2.4 Timing analysis . 21
A.2.5 Pre-processing conditions in differential analysis . 22
A.2.6 Pass / fail condition . 22
A.3 Security level 4 . 22
A.3.1 Time limit . 22
A.3.2 SPA and SEMA . 22
A.3.3 DPA and DEMA . 22
A.3.4 Timing analysis . 23
A.3.5 Pre-processing conditions in differential analysis . 23
© ISO/IEC 2023 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO/IEC FDIS 17825:2023(E)
A.3.6 Pass / fail condition . 23
Annex B (informative) Requirements for measurement apparatus . 24
B.1 General . 24
B.2 Speed . 24
B.3 Resolution . 24
B.4 Capacity . 24
B.5 Probe . 24
Annex C (informative) Associated security functions . 25
Annex D (informative) Emerging attacks . 27
D.1 Overview . 27
D.2 Template attack . 27
D.3 Side-channel collision attack . 27
D.4 Sophisticated attacks on asymmetric cryptography . 27
D.4.1 Doubling attack . 27
D.4.2 Markov SPA/SEMA. 27
D.4.3 Address-Bit DPA/DEMA . 28
D.5 Refined SPA/SEMA . 29
D.6 Use of new emerging side-channels . 29
D.7 Timing variation due to power consumption . 29
Annex E (informative) Quality criteria for measurement setups . 30
E.1 Electronic noise . 30
E.1.1 Noise of the power supply . 30
E.1.2 Noise of the clock generator . 30
E.1.3 Conducted and radiated emissions . 30
E.1.4 Quantisation noise . 30
E.2 Switching noise . 30
Annex F (informative) Chosen-input method to accelerate leakage analysis . 32
F.1 Overview . 32
F.2 The method outline . 32
Annex G (informative) Reasons that a side-channel is assessed as not measurable . 33
G.1 Purpose . 33
G.2 Examples . 33
Annex H (informative) Information about leakage location in relation to algorithm time . 34
H.1 Purpose . 34
H.2 Examples of non-sensitive leakage time . 34
iv © ISO/IEC 2023 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/IEC FDIS 17825:2023(E)
Bibliography . 35
© ISO/IEC 2023 – All rights reserved v

---------------------- Page: 5 ----------------------
ISO/IEC FDIS 17825:2023(E)
Contents
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 3
5 Document organization . 4
6 Non-invasive attack methods. 4
7 Non-invasive attack test methods . 8
7.1 General . 8
7.2 Test strategy . 8
7.3 Side-channel analysis workflow . 8
7.3.1 Core test flow . 8
7.3.2 Side-channel resistance test framework . 10
7.3.3 Required vendor information . 11
7.3.4 TA leakage analysis . 12
7.3.5 SPA/SEMA leakage analysis . 14
7.3.6 DPA/DEMA leakage analysis . 15
8 Side-channel analysis of symmetric-key cryptosystems . 17
8.1 General . 17
8.2 Timing attacks . 17
8.3 SPA/SEMA. 18
8.3.1 Attacks on key derivation process . 18
8.3.2 Side-channel collision attacks . 18
8.4 DPA/DEMA . 18
9 ASCA on asymmetric cryptography . 21
9.1 General . 21
9.2 Detailed side-channel resistance test framework . 22
9.3 Timing attacks . 23
9.3.1 General . 23
9.3.2 Standard timing analysis . 24
9.3.3 Micro-architectural timing analysis . 25
9.4 SPA/SEMA. 25
9.5 DPA/DEMA . 25
Annex A (normative) Non-invasive attack mitigation pass/fail test metrics . 27
Annex B (informative) Requirements for measurement apparatus . 30
Annex C (informative) Associated security functions . 31
Annex D (informative) Emerging attacks . 33
Annex E (informative) Quality criteria for measurement setups . 37
Annex F (informative) Chosen-input method to accelerate leakage analysis . 39
Annex G (informative) Reasons that a side-channel is assessed as not measurable . 40
vi © ISO/IEC 2023 – All rights reserved

---------------------- Page: 6 ----------------------
ISO/IEC FDIS 17825:2023(E)
Annex H (informative) Information about leakage location in relation to algorithm time . 41
Bibliography . 42

© ISO/IEC 2023 – All rights reserved vii

---------------------- Page: 7 ----------------------
ISO/IEC FDIS 17825:2023(E)
Formatted: Foreword Title
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commis-
sion) form the specialized system for worldwide standardization. National bodies that are members of ISO or
IEC participate in the development of International Standards through technical committees established by the
respective organization to deal with particular fields of technical activity. ISO and IEC technical committees
collaborate in fields of mutual interest. Other international organizations, governmental and non-governmen-
tal, in liaison with ISO and IEC, also take part in the work.
The procedures used to develop this document and those intended for its further maintenance are described in
Formatted: Indent: Left 0 ch
the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC
Directives, Part 2 (see www.iso.org/directiveswww.iso.org/directives or www.iec.ch/members_experts/ref-
docswww.iec.ch/members_experts/refdocs).
ISO and IEC draw attention to the possibility that the implementation of this document may involve the use of
(a) patent(s). ISO and IEC take no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO and IEC had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are cau-
tioned that this may not represent the latest information, which may be obtained from the patent database
available at www.iso.org/patents and https://patents.iec.ch.www.iso.org/patents and https://patents.iec.ch.
ISO and IEC shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not constitute
an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade Organiza-
tion (WTO) principles in the Technical Barriers to Trade (TBT) see www.iso.org/iso/fore-
word.html.www.iso.org/iso/foreword.html. In the IEC, see www.iec.ch/understanding-stand-
ardswww.iec.ch/understanding-standards.
This document was prepared by Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee
SC 27, Information security, cybersecurity and privacy protection.
This second edition cancels and replaces the first edition (ISO/IEC 17825:2016), which has been technically
revised.
The main changes are as follows:
— test methods have been updated as per research trends;
— an introduction has been added which states the expectations in terms of security level of this document;
— requirements have been numbered. This help ensuring to ensure their traceability.
Formatted: Font color: Auto
Formatted: Font color: Auto
Any feedback or questions on this document should be directed to the user’s national standards body. A com-
plete listing of these bodies can be found at www.iso.org/members.html and www.iec.ch/national-commit-
teeswww.iso.org/members.html and www.iec.ch/national-committees.

viii © ISO/IEC 2023 – All rights reserved

---------------------- Page: 8 ----------------------
ISO/IEC FDIS 17825:2023(E)
Introduction
Testing requires defined constants, which are derived from an axiomatic analysis of the security problem. The
security assurance levels are bound to the testing and remaining risks. The testing approach can be character-
ized as follows:
a) Testing soundness
1) FormalA formal description of empirical closed-box testing provides the soundness, in the context of
the attack, because the testing adheres to an accepted methodology.
2) The application of the methodology does not ensure that all possible attacks are covered. Testing al-
lows for weakness detection in a system; hence, it increases the confidence in a system's ability to
withstand a set of simulated attacks. The implemented formalism allows to detect weaknesses, and the
outcome is a reasonable level attested by tests.
3) The level of assurance that can be reached with the methodology in this document is a "“con-
trolled"” level of "“reasonable"” confidence level, which is the level low to medium. Level high is not
reachable due to the closed-box approach. The meaning of "“reasonable"” is determined by the cus-
tomer's risk threshold. The tester is defining the level of reasonability, in accordance with a security
level target.
4) Testing is guided by a strategy, which allows for transparency in the methodology and outcomes.
5) The methodology is device-class specific. The pass/fail criteria should take into account the class of
devices under test. For example, the criteria for devices with a deterministic behaviour (i.e. bare
metal), and for devices with a complex software stack should be different.
6) Security testing is an "“estimation"” when based upon noisy measurements, or when the tester does
not have full control of the implementation under test (IUT).
[68]
b) Repeatability (as per ISO/IEC 17025:2017 ,, 7.2.2.4)
Formatted: Default Paragraph Font
Formatted: std_section
Repeatability means similar results from the same (i.e.,. repeated) methodology, while reproducibility
means similar results from similar methodology. Security evaluation is an estimation based on noisy meas-
urements, on IUT whose behaviour is probably not in full control of the tester. In this document, there is a
prerequisite that the IUT is closed-box, which can behave in a non-deterministic manner (at least, its inter-
nals – owing to some intentional randomization used as a protection). Furthermore, the test can only be
carried out based on external observations and findings. As a result, the objective is to document a formal
and transparent process of testing, where independent tests can be reproduced with similar expected re-
sults (as much as possible, within reasonable bounds). The methodologies are similar (e.g.,. executed by
two testers) in that they yield similar outcome.
c) Cost of testing
1) The objective is to devote the right amount of effort for the testing of a given assurance level. Cost
effectiveness of the testing has a direct implication on assuring a certain level of security. Cost of testing
includes, but is not limited to:
i ) Level of expertise and experience: Consequence/implication of using an already formalized pro-
cess (agnostic in the IUT). The testers require skills and competencies.
© ISO/IEC 2023 – All rights reserved ix

---------------------- Page: 9 ----------------------
ISO/IEC FDIS 17825:2023(E)
ii) Time: Elapsed time for data acquisition, even though the procedure is automated.
[69]
iii) Equipment: The cost impact of equipment is covered in ISO/IEC 20085-1:2019 (requirements)
[70]
and ISO/IEC 20085-2:2020 (calibration).
2) This document aims to keep cost moderate. A threshold is reached in the assurance level up to a certain
number of traces captured. The level of assurance does not increase significantly more beyond the
threshold. The prescribed methodology cannot exceed a certain level of assurance by its design.
As a consequence of trade-offs made during the definition of this document andThe following statements apply
as an artefactartifact of the methodology used:
d) Closed-box testing limits this methodology to exclusively test for leakage that does not account for specific
features of a given algorithm’s implementation (e.g. implementation specificities, such as parallel execution
of unrelated cryptographic operations, or countermeasures, such as random masking, implementation of
field arithmetic in elliptic curve cryptography).
e) Testing only considers leakage during tested cryptographic operations using keys. By design the process
does not look for other potential sources of leakage (e.g. emissions during transit of keys over internal bus).
f) Results are dependent on the data- sets and quality of equipment used during acquisition. Attackers with
larger resources can still be able to exploit attack paths tested by this methodology, even if they had passed
the test based on increased resources and effort.
g) More sophisticated attacks can be applied and succeed. More sophisticated attacks refersrefer to attacks
other than conventional ones, for example the attacks that are particular to asymmetric ciphers (see 9.2).
Formatted: cite_sec
h) Each specific application/cryptographic module API instance also requires a delta evaluation on top of the
generic tests in this document. Such areas of assessment should include application-specific non-paramet-
ric module usage threats, such as traffic analysis, manipulation of logical order or scope of external opera-
tions.
Formatted: Font: Times New Roman, 12 pt, English
(United States)
In this document, requirements are numbered.
...

FINAL
INTERNATIONAL ISO/IEC
DRAFT
STANDARD FDIS
17825
ISO/IEC JTC 1/SC 27
Information technology — Security
Secretariat: DIN
techniques — Testing methods for
Voting begins on:
2023-09-01 the mitigation of non-invasive attack
classes against cryptographic modules
Voting terminates on:
2023-10-27
Techonologie de l'information — Techniques de sécurité — Methodes
de test pour la protection contre les attaques non intrusives des
modules cryptographiques
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/IEC FDIS 17825:2023(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO/IEC 2023

---------------------- Page: 1 ----------------------
ISO/IEC FDIS 17825:2023(E)
FINAL
INTERNATIONAL ISO/IEC
DRAFT
STANDARD FDIS
17825
ISO/IEC JTC 1/SC 27
Information technology — Security
Secretariat: DIN
techniques — Testing methods for
Voting begins on:
the mitigation of non-invasive attack
classes against cryptographic modules
Voting terminates on:
Techonologie de l'information — Techniques de sécurité — Methodes
de test pour la protection contre les attaques non intrusives des
modules cryptographiques
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
RECIPIENTS OF THIS DRAFT ARE INVITED TO
ISO copyright office
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
CP 401 • Ch. de Blandonnet 8
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
CH-1214 Vernier, Geneva
DOCUMENTATION.
Phone: [phone]
IN ADDITION TO THEIR EVALUATION AS
Reference number
Email: [e-mail]
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/IEC FDIS 17825:2023(E)
Website: www.iso.org
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
Published in Switzerland
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
ii
  © ISO/IEC 2023 – All rights reserved
NATIONAL REGULATIONS. © ISO/IEC 2023

---------------------- Page: 2 ----------------------
ISO/IEC FDIS 17825:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms.3
5 Document organization . 4
6 Non-invasive attack methods .4
7 Non-invasive attack test methods .7
7.1 General . 7
7.2 Test strategy . 7
7.3 Side-channel analysis workflow . 8
7.3.1 Core test flow. 8
7.3.2 Side-channel resistance test framework . 8
7.3.3 Required vendor information . 9
7.3.4 TA leakage analysis . 10
7.3.5 SPA/SEMA leakage analysis . 11
7.3.6 DPA/DEMA leakage analysis .12
8 Side-channel analysis of symmetric-key cryptosystems .13
8.1 General .13
8.2 Timing attacks .13
8.3 SPA/SEMA . 13
8.3.1 Attacks on key derivation process . 13
8.3.2 Side-channel collision attacks . 14
8.4 DPA/DEMA . 14
9 ASCA on asymmetric cryptography .16
9.1 General . 16
9.2 Detailed side-channel resistance test framework . 17
9.3 Timing attacks . 18
9.3.1 General . 18
9.3.2 Standard timing analysis . 18
9.3.3 Micro-architectural timing analysis . 19
9.4 SPA/SEMA . 19
9.5 DPA/DEMA . 19
Annex A (normative) Non-invasive attack mitigation pass/fail test metrics .21
Annex B (informative) Requirements for measurement apparatus .24
Annex C (informative) Associated security functions .25
Annex D (informative) Emerging attacks.27
Annex E (informative) Quality criteria for measurement setups .30
Annex F (informative) Chosen-input method to accelerate leakage analysis .32
Annex G (informative) Reasons that a side-channel is assessed as not measurable .33
Annex H (informative) Information about leakage location in relation to algorithm time .34
Bibliography .35
iii
© ISO/IEC 2023 – All rights reserved

---------------------- Page: 3 ----------------------
ISO/IEC FDIS 17825:2023(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
The procedures used to develop this document and those intended for its further maintenance
are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria
needed for the different types of document should be noted. This document was drafted in
accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives or
www.iec.ch/members_experts/refdocs).
ISO and IEC draw attention to the possibility that the implementation of this document may involve the
use of (a) patent(s). ISO and IEC take no position concerning the evidence, validity or applicability of
any claimed patent rights in respect thereof. As of the date of publication of this document, ISO and IEC
had not received notice of (a) patent(s) which may be required to implement this document. However,
implementers are cautioned that this may not represent the latest information, which may be obtained
from the patent database available at www.iso.org/patents and https://patents.iec.ch. ISO and IEC shall
not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html. In the IEC, see www.iec.ch/understanding­standards.
This document was prepared by Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 27, Information security, cybersecurity and privacy protection.
This second edition cancels and replaces the first edition (ISO/IEC 17825:2016), which has been
technically revised.
The main changes are as follows:
— test methods have been updated as per research trends;
— an introduction has been added which states the expectations in terms of security level of this
document;
— requirements have been numbered to ensure their traceability.
Any feedback or questions on this document should be directed to the user’s national standards
body. A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national­committees.
iv
  © ISO/IEC 2023 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/IEC FDIS 17825:2023(E)
Introduction
Testing requires defined constants, which are derived from an axiomatic analysis of the security
problem. The security assurance levels are bound to the testing and remaining risks. The testing
approach can be characterized as follows:
a) Testing soundness
1) A formal description of empirical closed-box testing provides the soundness, in the context of
the attack, because the testing adheres to an accepted methodology.
2) The application of the methodology does not ensure that all possible attacks are covered.
Testing allows for weakness detection in a system; hence, it increases the confidence in a
system's ability to withstand a set of simulated attacks. The implemented formalism allows to
detect weaknesses, and the outcome is a reasonable level attested by tests.
3) The level of assurance that can be reached with the methodology in this document is a
“controlled” level of “reasonable” confidence level, which is the level low to medium. Level high
is not reachable due to the closed-box approach. The meaning of “reasonable” is determined by
the customer's risk threshold. The tester is defining the level of reasonability, in accordance
with a security level target.
4) Testing is guided by a strategy, which allows for transparency in the methodology and
outcomes.
5) The methodology is device-class specific. The pass/fail criteria should take into account the
class of devices under test. For example, the criteria for devices with a deterministic behaviour
(i.e. bare metal), and for devices with a complex software stack should be different.
6) Security testing is an “estimation” when based upon noisy measurements, or when the tester
does not have full control of the implementation under test (IUT).
b) Repeatability (as per ISO/IEC 17025:2017, 7.2.2.4)
Repeatability means similar results from the same (i.e. repeated) methodology, while
reproducibility means similar results from similar methodology. Security evaluation is an
estimation based on noisy measurements, on IUT whose behaviour is probably not in full control
of the tester. In this document, there is a prerequisite that the IUT is closed-box, which can behave
in a non­deterministic manner (at least, its internals – owing to some intentional randomization
used as a protection). Furthermore, the test can only be carried out based on external observations
and findings. As a result, the objective is to document a formal and transparent process of testing,
where independent tests can be reproduced with similar expected results (as much as possible,
within reasonable bounds). The methodologies are similar (e.g. executed by two testers) in that
they yield similar outcome.
c) Cost of testing
1) The objective is to devote the right amount of effort for the testing of a given assurance level.
Cost effectiveness of the testing has a direct implication on assuring a certain level of security.
Cost of testing includes, but is not limited to:
i) Level of expertise and experience: Consequence/implication of using an already formalized
process (agnostic in the IUT). The testers require skills and competencies.
ii) Time: Elapsed time for data acquisition, even though the procedure is automated.
iii) Equipment: The cost impact of equipment is covered in ISO/IEC 20085-1:2019
(requirements) and ISO/IEC 20085-2:2020 (calibration).
2) This document aims to keep cost moderate. A threshold is reached in the assurance level up to a
certain number of traces captured. The level of assurance does not increase significantly more
v
© ISO/IEC 2023 – All rights reserved

---------------------- Page: 5 ----------------------
ISO/IEC FDIS 17825:2023(E)
beyond the threshold. The prescribed methodology cannot exceed a certain level of assurance
by its design.
The following statements apply as an artifact of the methodology used:
d) Closed-box testing limits this methodology to exclusively test for leakage that does not account for
specific features of a given algorithm’s implementation (e.g. implementation specificities, such as
parallel execution of unrelated cryptographic operations, or countermeasures, such as random
masking, implementation of field arithmetic in elliptic curve cryptography).
e) Testing only considers leakage during tested cryptographic operations using keys. By design the
process does not look for other potential sources of leakage (e.g. emissions during transit of keys
over internal bus).
f) Results are dependent on the data sets and quality of equipment used during acquisition. Attackers
with larger resources can still exploit attack paths tested by this methodology, even if they had
passed the test based on increased resources and effort.
g) More sophisticated attacks can be applied and succeed. More sophisticated attacks refer to attacks
other than conventional ones, for example the attacks that are particular to asymmetric ciphers
(see 9.2).
h) Each specific application/cryptographic module API instance also requires a delta evaluation on
top of the generic tests in this document. Such areas of assessment should include application­
specific non-parametric module usage threats, such as traffic analysis, manipulation of logical
order or scope of external operations.
In this document, requirements are numbered. By convention, the requirements are labelled as [CC.NN],
where CC represents the clause number (e.g. 06 means Clause 6), and NN represents the requirement
position within the Clause (e.g. the first requirement of Claude 6 is referred to as [06.01]). The purpose of
labelled requirements is to ease the generation of documents showing compliance with this document,
and their traceability for testers.
vi
  © ISO/IEC 2023 – All rights reserved

---------------------- Page: 6 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/IEC FDIS 17825:2023(E)
Information technology — Security techniques — Testing
methods for the mitigation of non-invasive attack classes
against cryptographic modules
1 Scope
This document specifies the non-invasive attack mitigation test metrics for determining conformance
to the requirements specified in ISO/IEC 19790:2012 for security levels 3 and 4. The test metrics are
associated with the security functions addressed in ISO/IEC 19790:2012. Testing is conducted at the
defined boundary of the cryptographic module and the inputs/outputs available at its defined boundary.
This document is intended to be used in conjunction with ISO/IEC 24759:2017 to demonstrate
conformance to ISO/IEC 19790:2012.
NOTE ISO/IEC 24759:2017 specifies the test methods used by testing laboratories to assess whether the
cryptographic module conforms to the requirements specified in ISO/IEC 19790:2012 and the test metrics
specified in this document for each of the associated security functions addressed in ISO/IEC 19790:2012.
The test approach employed in this document is an efficient “push-button” approach, i.e. the tests are
technically sound, repeatable and have moderate costs.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 19790:2012, Information technology — Security techniques — Security requirements for
cryptographic modules
ISO/IEC 24759:2017, Information technology — Security techniques — Test requirements for cryptographic
modules
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 19790 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
advanced side-channel analysis
ASCA
advanced exploitation of the instantaneous side-channels emitted by a cryptographic device that
depends on the data it processes and on the operation it performs to retrieve secret parameters
3.2
correlation power analysis
CPA
analysis where the correlation coefficient is used as the statistical method
1
© ISO/IEC 2023 – All rights reserved

---------------------- Page: 7 ----------------------
ISO/IEC FDIS 17825:2023(E)
3.3
critical security parameter class
CSP class
class into which a critical security parameter (3.3) is categorised
EXAMPLE Cryptographic keys, authentication data such as passwords, PINs, biometric authentication data.
3.4
differential electromagnetic analysis
DEMA
analysis of the variations of the electromagnetic field emanated from a cryptographic module, using
statistical methods on a large number of measured electromagnetic emanations values for determining
whether the assumption of the divided subsets of a secret parameter is correct, for the purpose of
extracting information correlated to security function operation
3.5
differential power analysis
DPA
analysis of the variations of the electrical power consumption of a cryptographic module, for the
purpose of extracting information correlated to cryptographic operation
3.6
electromagnetic analysis
EMA
analysis of the electromagnetic field emanated from a cryptographic module as the result of its logic
circuit switching, for the purpose of extracting information correlated to security function operation
and subsequently the values of secret parameters such as cryptographic keys
3.7
implementation under test
IUT
implementation which is tested based on non­invasive methods
3.8
power analysis
PA
analysis of the electric power consumption of a cryptographic module, for the purpose of extracting
information correlated to the security function operation and subsequently the values of secret
parameters such as cryptographic keys
3.9
side-channel analysis
SCA
exploitation of the fact that the instantaneous side-channels emitted by a cryptographic device depends
on the data it processes and on the operation it performs to retrieve secret parameters
3.10
side-channel collision attack
powerful category of side-channel analysis (3.9) that usually combines leakage from distinct points in
time, making them inherently bivariate
3.11
simple electromagnetic analysis
SEMA
direct (primarily visual) analysis of patterns of instruction execution or logic circuit activities, obtained
through monitoring the variations in the electromagnetic field emanated from a cryptographic module,
for the purpose of revealing the features and implementations of cryptographic algorithms and
subsequently the values of secret parameters
2
  © ISO/IEC 2023 – All rights reserved

---------------------- Page: 8 ----------------------
ISO/IEC FDIS 17825:2023(E)
3.12
simple power analysis
SPA
direct (primarily visual) analysis of patterns of instruction execution (or execution of individual
instructions), in relation to the electrical power consumption of a cryptographic module, for the
purpose of extracting information correlated to a cryptographic operation
3.13
timing analysis
TA
analysis of the variations of the response or execution time of an operation in a security function, which
can reveal knowledge of or about a security parameter such as a cryptographic key or PIN
4 Symbols and abbreviated terms
ASCA advanced side-channel analysis
AES advanced encryption standard
CPA correlation power analysis
CSP critical security parameter
DEMA differential electromagnetic analysis
DES data encryption standard
DLC discrete logarithm cryptography
DPA differential power analysis
DSA digital signature algorithm
ECC elliptic curve cryptography
ECDSA elliptic curve digital signature algorithm
EM electromagnetic
EMA electromagnetic analysis
HMAC keyed-hashing message authentication code
IFC integer factorization cryptography
IUT implementation under test
MAC message authentication code
PA power analysis
PC personal computer
PCB printed circuit board
PKCS public-key cryptography standards
RBG random bit generator
RNG random number generator
3
© ISO/IEC 2023 – All rights reserved

---------------------- Page: 9 ----------------------
ISO/IEC FDIS 17825:2023(E)
RSA Rivest Shamir Adleman
SCA side-channel analysis
SEMA simple electromagnetic analysis
SHA secure hash algorithm
SNR signal to noise ratio
SPA simple power analysis
USB universal serial bus
TA timing analysis
· multiplication symbol
5 Document organization
Clause 6 specifies the non-invasive attack methods that a cryptographic module shall mitigate against
for conformance to ISO/IEC 19790:2012.
Clause 7 specifies the non-invasive attack test methods.
Clause 8 specifies the test methods for side-channel analysis of symmetric-key cryptosystems.
Clause 9 specifies the test methods for side-channel analysis of asymmetric-key cryptosystems.
This document shall be used together with ISO/IEC 24759:2017 to demonstrate conformance to
ISO/IEC 19790:2012.
6 Non-invasive attack methods
This clause specifies the non-invasive attack methods that shall [06.01] be addressed to ensure
conformance with ISO/IEC 19790:2012.
The non-invasive attacks use side-channels (information gained from the physical implementation of a
cryptosystem) emitted by the implementation under test (IUT), such as:
— the power consumption of the IUT,
— the electromagnetic emissions of the IUT,
— the computation time of the IUT.
[49]
The number of possible side­channels can increase in the future (e.g. photonic emissions, acoustic
emanations).
In order to be more formal in the taxonomy of the attacks, a formalism allows the relationships to be
highlighted between the different attacks and to have a systematic way to describe a new attack.
An attack is described in the following way:
­­­­
KKK refers to the order of the attack (e.g. “2O” for second order attack).
4
  © ISO/IEC 2023 – All rights reserved

---------------------- Page: 10 ----------------------
ISO/IEC FDIS 17825:2023(E)
YYY refers to the statistical treatment used in the attack (e.g. “S” for simple, “C” for correlation, “MI”
for mutual information, “ML” for maximum likelihood, “D” for difference of means, “LR” for linear
regression, etc.).
NOTE 1 Other statistical treatments can be inserted like “dOC” which corresponds to a correlation treatment
exploiting dth order moments (obtained for instance, by raising each targeted point in the traces to a power d, or
by combining d points per trace before processing the correlation).
XXX refers to the kind of observed side channel: e.g. “PA” for power analysis, “EMA” for electromagnetic
analysis, “TA” for timing analysis, etc.
ZZZ can refer to the profiled (“P”) or unprofiled (“UP”) characteristic of the attack. This is optional and
the default value is “UP”.
[43]
TTT refers to the direction of the attack (e.g. “V” for vertical, “H” for horizontal, “R” for rectangle).
Figure 1 — Taxonomy of non-invasive attacks
NOTE 2 Instead of just splitting advanced side-channel analysis (ASCA) into univariate and multivariate
cases, the classification can still be refined by separating attacks based on “variable distinguishers” (which focus
on a particular moment of the distribution of the target variable) from those based on “pdf distinguishers” (non­
invasive analysis distinguisher which requires as input an estimation of the leakage probability density function
knowing the secret key). The first category includes ASCA based on correlation or on the linear regression
techniques. The second one includes maximum likelihood and mutual information attacks for instance.
NOTE 3 The simple power analysis (SPA) and simple electromagnetic analysis (SEMA) attack methods include
some extensions to basic SPA and SEMA attacks (i.e. template attack). The differential power analysis (DPA) and
differential electromagnetic analysis (D
...