ISO/IEC 18031

Information technology — Security techniques — Random bit generation

This document specifies a conceptual model for a random bit generator for cryptographic purposes, together with the elements of this model. This document specifies the characteristics of the main elements required for both non-deterministic and deterministic random bit generators. It also establishes the security requirements for both non-deterministic and deterministic random bit generators. Techniques for statistical testing of random bit generators for the purposes of independent verification or validation and detailed designs for such generators are outside the scope of this document.

Technologies de l'information — Techniques de sécurité — Génération de bits aléatoires

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: 6000 - International Standard under publication
• Due Date: 07-Jan-2025
• Completion Date: 07-Jan-2025

Relations

• Revises: ISO/IEC 18031:2011 - Information technology — Security techniques — Random bit generation
• Effective Date: 06-Jun-2022
• Revises: ISO/IEC 18031:2011/Amd 1:2017 - Information technology — Security techniques — Random bit generation — Amendment 1: Deterministic random bit generation
• Effective Date: 06-Jun-2022

Standards Content (Sample)

International
Standard
Third edition
Information technology —
Security techniques — Random bit
generation
Technologies de l'information — Techniques de sécurité —
Génération de bits aléatoires
PROOF/ÉPREUVE
Reference number
© ISO/IEC 2024
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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
© ISO/IEC 2024 – All rights reserved
ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 7
5 Properties and requirements of a random bit generator . 8
5.1 Properties of arandom bit generator .8
5.2 Requirements of an RBG .9
5.3 Additional information for an RBG . .10
6 RBG model . 10
6.1 Conceptual functional model for random bit generation .10
6.2 RBG basic components .11
6.2.1 Introduction to the RBG basic components .11
6.2.2 Randomness source .11
6.2.3 Additional inputs . . 12
6.2.4 Internal state . 12
6.2.5 Internal state transition functions . 13
6.2.6 Output generation function .14
6.2.7 Health test . 15
7 Types of RBGs .15
7.1 Introduction to the types of RBGs . . 15
7.2 Non-deterministic random bit generators .16
7.3 Deterministic random bit generators .17
7.4 The RBG spectrum .17
8 Overview and requirements for an NRBG . 17
8.1 NRBG overview .17
8.2 Functional model of an NRBG .18
8.3 NRBG entropy sources . 20
8.3.1 General . 20
8.3.2 Primary entropy source for an NRBG . 20
8.3.3 Physical entropy sources for an NRBG . 22
8.3.4 NRBG non-physical entropy sources . 22
8.3.5 NRBG additional entropy sources . 23
8.3.6 Hybrid NRBGs .24
8.4 NRBG additional inputs .24
8.4.1 NRBG additional inputs overview.24
8.4.2 Requirements for NRBG additional inputs.24
8.5 NRBG internal state . 25
8.5.1 NRBG internal state overview. 25
8.5.2 Requirements for the NRBG internal state . 25
8.5.3 Additional information for the NRBG internal state . 26
8.6 NRBG internal state transition functions . 26
8.6.1 NRBG internal state transition functions overview . 26
8.6.2 Requirements for the NRBG internal state transition functions .27
8.6.3 Recommendations for the NRBG internal state transition functions .27
8.7 NRBG output generation function .27
8.7.1 NRBG output generation function overview .27
8.7.2 Requirements for the NRBG output generation function . 28
8.8 NRBG health tests . 28
8.8.1 NRBG health tests overview . 28
8.8.2 General NRBG health test requirements. 29
PROOF/ÉPREUVE
© ISO/IEC 2024 – All rights reserved
iii
8.8.3 NRBG health test on deterministic components . 29
8.8.4 NRBG health tests within entropy sources . 30
8.8.5 NRBG health tests on random output .31
8.9 NRBG component interaction .32
8.9.1 NRBG component interaction overview .32
8.9.2 Requirements for NRBG component interaction .32
8.9.3 Recommendations for NRBG component interaction . 33
9 Overview and requirements for a DRBG .33
9.1 DRBG overview . 33
9.2 Functional model of a DRBG . 33
9.3 DRBG randomness source . 36
9.3.1 Primary randomness source for a DRBG . 36
9.3.2 Generating seed values for a DRBG .37
9.3.3 Additional randomness sources for a DRBG . 38
9.3.4 Hybrid DRBGs . 38
9.4 Additional inputs for a DRBG . 38
9.5 Internal state for a DRBG . 39
9.6 Internal state transition function for a DRBG . 39
9.7 Output generation function for a DRBG . 40
9.8 Health tests for a DRBG . 40
9.8.1 DRBG health tests overview . 40
9.8.2 DRBG health test .41
9.8.3 DRBG deterministic algorithm test .
...

Formatted: Centered
ISO/IEC DIS 18031:2023(E2024(en) Style Definition: Heading 1
Style Definition: Heading 2
ISO/IEC JTC 1/SC 27/WG 2
Style Definition: Heading 3
Secretariat: DIN
Style Definition: Heading 4
Style Definition: Heading 5
Date: 2023-11-202024-12-10
Style Definition: Heading 6
Information security — Random bit generation
Style Definition: Default Paragraph Font
Style Definition: ANNEX
Technologies de l'information — Techniques de sécurité — Génération de bits aléatoires
Style Definition: 変更箇所1: No widow/orphan control,
Don't hyphenate
Style Definition: Base_Heading: Font:
Style Definition: Base_Text: Font:
Style Definition: AMEND Terms Heading
Style Definition: AMEND Heading 1 Unnumbered
Formatted: French (Switzerland)
Formatted: French (Switzerland)
Formatted: French (Switzerland)
Formatted: Centered
ISO/IEC DIS 18031:2023(E)
© ISO/IEC 2023 2024
Formatted: Indent: Left: 0.5 cm, Right: 0.5 cm, Space
Before: 0 pt, No page break before, Adjust space
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no
between Latin and Asian text, Adjust space between
part of this publication may be reproduced or utilized otherwise in any form or by any means, Asian text and numbers
electronic or mechanical, including photocopying, or posting on the internet or an intranet, without
Formatted: Default Paragraph Font
prior written permission. Permission can be requested from either ISO at the address below or
ISO’sISO's member body in the country of the requester.
ISO copyright officeCopyright Office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Formatted: Indent: Left: 0.5 cm, First line: 0 cm, Right:
0.5 cm, 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: 0.5 cm, First line: 0 cm, Right:
0.5 cm, Adjust space between Latin and Asian text,
Published in Switzerland. Adjust space between Asian text and numbers
ii © ISO/IEC 2023 – All rights reserved

ISO/IEC DIS 18031:2023(E)
Contents
Foreword . vii
Introduction . viii
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 9
4 Symbols . 17
5 Properties and requirements of an RBG . 18
5.1 Properties of an RBG . 18
5.2 Requirements of an RBG . 19
5.3 Recommendations for an RBG . 20
6 RBG model . 21
6.1 Conceptual functional model for random bit generation . 21
6.2 RBG basic components . 21
6.2.1 Introduction to the RBG basic components . 21
6.2.2 Randomness source . 22
6.2.3 Additional inputs . 23
6.2.4 Internal state . 23
6.2.5 Internal state transition functions . 25
6.2.6 Output generation function . 26
6.2.7 Health test . 27
7 Types of RBGs . 27
7.1 Introduction to the types of RBGs . 27
7.2 Non-deterministic random bit generators . 28
7.3 Deterministic random bit generators . 29
7.4 The RBG spectrum . 29
8 Overview and requirements for an NRBG . 30
8.1 NRBG overview . 30
8.2 Functional model of an NRBG . 30
8.3 NRBG entropy sources . 33
8.3.1 General . 33
8.3.2 Primary entropy source for an NRBG . 33
8.3.3 Physical entropy sources for an NRBG . 35
8.3.4 NRBG non-physical entropy sources . 36
8.3.5 NRBG additional entropy sources . 36
8.3.6 Hybrid NRBGs . 38
8.4 NRBG additional inputs . 38
8.4.1 NRBG additional inputs overview . 38
8.4.2 Requirements for NRBG additional inputs . 38
8.5 NRBG internal state . 39
8.5.1 NRBG internal state overview . 39
8.5.2 Requirements for the NRBG internal state . 39
8.5.3 Recommendations for the NRBG internal state . 40
8.6 NRBG internal state transition functions . 41
8.6.1 NRBG internal state transition functions overview . 41
© ISO/IEC 2023 – All rights reserved iii

ISO/IEC DIS 18031:2023(E)
8.6.2 Requirements for the NRBG internal state transition functions . 42
8.6.3 Recommendations for the NRBG internal state transition functions . 42
8.7 NRBG output generation function . 42
8.7.1 NRBG output generation function overview . 42
8.7.2 Requirements for the NRBG output generation function . 42
8.8 NRBG health tests . 43
8.8.1 NRBG health tests overview . 43
8.8.2 General NRBG health test requirements . 44
8.8.3 NRBG health test on deterministic components . 45
8.8.4 NRBG health tests within entropy sources . 46
8.8.5 NRBG health tests on random output . 47
8.9 NRBG component interaction . 48
8.9.1 NRBG component interaction overview . 48
8.9.2 Requirements for NRBG component interaction . 49
8.9.3 Recommendations for NRBG component interaction . 49
9 Overview and requirements for a DRBG . 49
9.1 DRBG overview . 49
9.2 Functional model of a DRBG . 50
9.3 DRBG randomness source . 53
9.3.1 Primary randomness source for a DRBG . 53
9.3.2 Generating seed values for a DRBG . 55
9.3.3 Additional randomness sources for a DRBG . 56
9.3.4 Hybrid DRBGs . 56
9.4 Additional inputs for a DRBG . 56
9.5 Internal state for a DRBG . 57
9.6 Internal state transition function for a DRBG . 58
9.7 Output generation function for a DRBG . 59
9.8 Health tests for a DRBG . 59
9.8.1 DRBG health tests overview . 59
9.8.2 DRBG health test . 60
9.8.3 DRBG deterministic algorithm test . 60
9.8.4 DRBG software/firmware integrity test . 60
9.8.5 DRBG critical functions test . 60
9.8.6 DRBG software/firmware load test . 60
9.8.7 DRBG manual key entry test . 61
9.8.8 Continuous Tests on Noise Sources in Entropy Sources . 61
9.9 Additional requirements for DRBG keys . 61
Annex A (normative) Combining RBGs . 64
Annex B (normative) Conversion methods for random number generation . 65
B.1 Techniques for generating random numbers . 65
B.2 The simple discard method . 65
B.3 The complex discard method . 65
B.4 The simple modular method . 66
B.5 The complex modular method . 66
B.6 The simple partial discard method . 66
B.7 The complex partial discard method .
...