ISO IEC 10118-4-1998 PDF

Full title and description

Information technology — Security techniques — Hash-functions — Part 4: Hash-functions using modular arithmetic (ISO/IEC 10118-4:1998). This part of ISO/IEC 10118 specifies two modular-arithmetic based hash functions (commonly referred to as MASH-1 and MASH-2) intended for environments where modular-arithmetic primitives are already available.

Abstract

This standard defines two hash-functions (MASH-1 and MASH-2) that compress messages of arbitrary but limited length into a hash-code whose length is determined by the prime modulus used in the reduction function. The functions use a round-function based on modular arithmetic and are intended to be scalable to match the input length of signature and identification mechanisms. Examples, padding rules, initialization values and reduction-function details are specified.

General information

• Status: Published (International Standard; confirmed in periodic reviews).
• Publication date: December 1998 (first edition).
• Publisher: ISO/IEC (JTC 1/SC 27 — Information security techniques).
• ICS / categories: 35.030 (IT security).
• Edition / version: Edition 1 (1998); standard has a technical corrigendum and an amendment issued in 2014.
• Number of pages: 23 (main document).

Note: a Technical Corrigendum 1 and an Amendment 1 (object identifiers) were published in 2014 to correct and extend the original text.

Scope

Specifies the construction, parameters and processing rules for two hash-functions based on modular arithmetic (MASH-1 and MASH-2). The standard defines required variables (modulus, exponent, initial value), padding and length-encoding rules, the round-function and the reduction-function (using a chosen prime), and includes informative examples of operation. The resulting hash length is determined by the size of the prime modulus, allowing scaling to target output sizes needed by other cryptographic mechanisms.

Key topics and requirements

• Definition and specification of two modular-arithmetic hash functions: MASH-1 and MASH-2.
• Round-function design based on modular multiplication and exponentiation.
• Rules for padding, appending length, splitting and expanding message blocks.
• Reduction-function using a chosen prime to produce the final hash-code of selectable length.
• Initialization values, parameter selection (modulus size, exponent), and security considerations (collision-resistance assumptions).
• Informative examples and test vectors for implementation guidance.

Typical use and users

Intended for cryptographic designers, implementers and evaluators working in environments where modular-arithmetic (large-integer) operations are already implemented (for example, systems that implement RSA-like or other modular-exponentiation algorithms). Typical users include security engineers, standards bodies, vendors of cryptographic libraries, and organisations implementing digital-signature or identification schemes that require a scalable hash output.

Related standards

Part of the ISO/IEC 10118 series (hash-functions). Other relevant parts include ISO/IEC 10118-1 (general model and terminology), ISO/IEC 10118-2 (hash-functions using an n-bit block cipher) and ISO/IEC 10118-3 (dedicated hash-functions). Implementers may also consider related cryptographic standards for block ciphers and signature schemes when integrating these hash functions.

Keywords

hash function, MASH-1, MASH-2, modular arithmetic, reduction function, padding, collision resistance, ISO/IEC 10118, IT security, JTC 1/SC 27

FAQ

Q: What is this standard?

A: ISO/IEC 10118-4:1998 specifies two hash-functions that use modular arithmetic (MASH-1 and MASH-2) to produce scalable hash-codes for cryptographic use.

Q: What does it cover?

A: It covers parameter selection (modulus, exponent, initial value), message preparation (padding and length encoding), the round-function and reduction-function, and examples — all necessary details to implement MASH-1 and MASH-2.

Q: Who typically uses it?

A: Cryptographic library implementers, security engineers, standards organisations and evaluators, and any system designers who already use modular-arithmetic primitives and need a standards-based hash function.

Q: Is it current or superseded?

A: The document was published in December 1998 (first edition). It received a Technical Corrigendum and an Amendment in 2014; the ISO record shows it has been periodically reviewed and was confirmed in ISO’s review cycle (confirmed as current in recent reviews). Users should check the latest ISO metadata or national adoption records for the absolute current status before relying on it in new projects.

Q: Is it part of a series?

A: Yes — ISO/IEC 10118 is a multi-part standard covering hash-functions. Parts include the general model (10118-1), block-cipher–based constructions (10118-2), dedicated hash-functions (10118-3) and this modular-arithmetic part (10118-4), among others.

Q: What are the key keywords?

A: MASH-1, MASH-2, modular arithmetic, hash-function, reduction function, ISO/IEC 10118, collision resistance, padding, initialization value.