ISO IEC 9797-2-2021 cor1-2024 PDF

Full title and description

ISO/IEC 9797-2:2021/Cor 1:2024 — Information security — Message authentication codes (MACs) — Part 2: Mechanisms using a dedicated hash-function — Technical Corrigendum 1. This corrigendum issues technical and editorial corrections that apply to the ISO/IEC 9797-2:2021 edition (Part 2 of the ISO/IEC 9797 MAC series).

Abstract

The underlying ISO/IEC 9797-2:2021 standard specifies message authentication code (MAC) algorithms that use a secret key together with a dedicated hash-function (or its round/sponge function) to compute an m‑bit MAC for data-integrity verification. The 2024 corrigendum corrects and clarifies items in the 2021 text to ensure unambiguous implementation and referencing.

General information

• Status: Published.
• Publication date: 28 November 2024 (corrigendum publication; applies to ISO/IEC 9797-2:2021).
• Publisher: International Organization for Standardization (ISO) in conjunction with IEC / JTC 1/SC 27.
• ICS / categories: 35.030 (IT security techniques).
• Edition / version: Edition 3 (base standard ISO/IEC 9797-2:2021; corrigendum document is the 2024 Technical Corrigendum 1).
• Number of pages: Corrigendum document: 3 pages. (Base standard ISO/IEC 9797-2:2021 is 52 pages.)

Scope

This Technical Corrigendum 1 provides corrections and editorial clarifications to ISO/IEC 9797-2:2021. The base Part 2 standard defines MAC mechanisms built on dedicated hash-functions (including use of hash round-functions or sponge constructions) and specifies algorithm variants, output lengths, truncation rules and associated security considerations; the corrigendum updates the 2021 text to correct errors and remove ambiguities that could affect implementation or interoperability.

Key topics and requirements

• Definition of MAC mechanisms that use a dedicated hash-function, including permitted constructions and options.
• Specification of keying and input processing (how the secret key is combined with the input to produce a keyed-hash MAC).
• Truncation and output-length rules for producing an m‑bit authentication tag.
• Security considerations and guidance on algorithm selection, parameter choices and expected resistance properties.
• Normative references and editorial fixes to ensure consistent interpretation and to correct any errors in the 2021 text (applied by the 2024 corrigendum).

Typical use and users

Users: cryptographic engineers, protocol designers, software and hardware implementers of MACs, security architects, evaluators and conformity assessors, and standards developers. Typical uses: specifying or implementing keyed-hash MACs for message integrity and authenticity in protocols, secure storage and secure communications where a dedicated hash-function based MAC is required.

Related standards

ISO/IEC 9797 series (Part 1: mechanisms using a block cipher; Part 3: mechanisms using a universal hash-function), ISO/IEC 10118 (hash-functions, including dedicated hash‑functions), and other JTC 1/SC 27 information-security standards. The corrigendum is explicitly linked to ISO/IEC 9797-2:2021.

Keywords

Message Authentication Code, MAC, keyed-hash, dedicated hash-function, keyed-hash MAC, truncation, message integrity, ISO/IEC 9797-2, corrigendum.

FAQ

Q: What is this standard?

A: It is the Technical Corrigendum 1 (2024) to ISO/IEC 9797-2:2021, which issues corrections and clarifications to the Part 2 standard for MAC mechanisms that use a dedicated hash-function.

Q: What does it cover?

A: The base Part 2 standard covers the specification of keyed-hash MAC algorithms (how a secret key and a dedicated hash-function or its internal function are used to compute an m‑bit MAC), choices for output length and truncation, and security considerations; the corrigendum fixes errors and clarifies the 2021 wording to ensure accurate implementation.

Q: Who typically uses it?

A: Cryptographers, implementers of security protocols (software/hardware), security architects, auditors and testing laboratories, and standards bodies that reference MAC algorithms for product or protocol specifications.

Q: Is it current or superseded?

A: The corrigendum was published in November 2024 and applies to the current 2021 edition of ISO/IEC 9797-2; it does not supersede the base standard but amends and corrects the 2021 text. As of the corrigendum publication (28 November 2024) the corrected 2021 edition remains the active Part 2 document.

Q: Is it part of a series?

A: Yes — ISO/IEC 9797 is a multi-part series on Message Authentication Codes: Part 1 (block-cipher mechanisms), Part 2 (dedicated hash-function mechanisms — this document), and Part 3 (universal hash-function mechanisms), maintained by JTC 1/SC 27.

Q: What are the key keywords?

A: MAC, message authentication code, keyed-hash, dedicated hash-function, tag truncation, message integrity, ISO/IEC 9797-2, corrigendum.