Overview
ISO/IEC 18031:2011/Amd 1:2017 is an amendment to the ISO/IEC 18031 family that explicitly addresses deterministic random bit generation (DRBG). The amendment adds an informative Annex K with concrete example cases for an MQ-based DRBG (MQ_DRBG), providing encoded systems of multivariate quadratic equations, test vectors, file checksums and format rules to help implementers and evaluators understand and test deterministic random bit generation methods.
Key topics and technical highlights
- Deterministic random bit generation (DRBG): The amendment supplements the base standard by documenting DRBG-related material and example instantiations.
- MQ_DRBG example cases: Annex K supplies 14 example settings that demonstrate how to encode a multivariate quadratic (MQ) deterministic generator, including:
- Bitstring P encoding a randomly selected system of MQ equations.
- Files with system coefficients and SHA‑1 checksums (e.g., “coefficients‑BL‑128‑Sec‑112‑F2.bin”).
- Input-output sequences for the Evaluate_MQ(P, x) function provided as hexadecimal vectors.
- Field and coefficient representation: Rules for representing field elements (GF(2^k)) as bitstrings of length field_size, with polynomial coefficients ordered by decreasing degree, and examples for field_size = 1, 2, 4, 6, 8, etc.
- Equation and system format: Specification of how to concatenate quadratic and linear coefficients and constants for each equation and for the full system (P), plus formats for input and output vectors (x, y, z).
- Rank and verification data: Each example includes rank-distribution results and minimum rank/weight requirements used to verify selection rules and structural properties of the MQ systems.
- Supporting files and reproducibility: Example coefficient files and test vectors are published at the ISO URL: http://standards.iso.org/iso/18031/
Practical applications and intended users
- Cryptographic implementers building deterministic RNGs or integrating MQ_DRBG instantiations into security products.
- Security evaluators and test laboratories performing functional testing and conformance checks against ISO/IEC 18031 formats and example vectors.
- Cryptographers and protocol designers researching algebraic constructions (multivariate quadratic systems) for PRNG/DRBG use.
- Standards bodies and auditors who need canonical examples and documented formats for assessment and interoperability testing.
Related standards and context
- This document is an amendment to ISO/IEC 18031:2011, prepared by ISO/IEC JTC 1/SC 27 (IT Security techniques). Annex K is primarily informative and intended to aid implementation, testing and verification of deterministic random bit generation using MQ constructions.
Keywords: ISO/IEC 18031, deterministic random bit generator, DRBG, MQ_DRBG, multivariate quadratic, random bit generation standard, cryptographic RNG, Annex K.
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