National foreword

This British Standard is the UK implementation of ISO/IEC 29128‑2:2026.

The UK participation in its preparation was entrusted to Technical Committee IST/33/3, Security Evaluation, Testing and Specification.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 September 2026.

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/understanding-standards.

This document was prepared by Technical Committee ISO/IEC/JTC 1, Information technology, Subcommittee SC 27, Information security, cybersecurity and privacy protection.

A list of all parts in the ISO/IEC 29128 series can be found on the ISO and IEC websites.

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/national-committees.

Introduction

Cryptographic protocols form the basis of secure applications. A thorough evaluation is necessary to confirm their expected behaviour before deployment.

The ISO/IEC 29128 series specifies methods for the verification and evaluation of cryptographic protocols.

ISO/IEC 29128‑1 specifies the formal verification process and the evidence produced by this process.

This document (see ISO/IEC 29128‑2) specifies the methodology and evaluation activities for collecting and submitting the evidence from the formal verification process to the evaluator and the testing laboratory.

ISO/IEC 29128‑3 specifies evaluation methods and activities for assessing a concrete implementation of a cryptographic protocol. It provides an assurance framework based on vulnerability assessment principles derived from the Common Criteria.

1 Scope

This document specifies an extension of evaluation methods and activities for cryptographic protocols based on ISO/IEC 15408‑4, which provides a framework for evaluation methods and activities. This document provides a mapping between the work items for cryptographic protocol evaluation and the associated evaluation activities or evaluation methods. Additionally, this document also provides security assurance classification based on the cryptographic assessment performed by automated provers in four different levels of increasing assurance.

2 Normative references

3 Terms and definitions

4 Security assessment and verification of cryptographic protocols

4.1 Overview

4.2 Prover

4.3 Models

5 Method for cryptographic protocol security evaluation

5.1 Overview

5.2 Scope of cryptographic evaluation method

5.3 Cryptographic protocol evaluation method

6 Activities for cryptographic protocol security evaluation

Bibliography