Overview
ISO/IEC 20897-1:2020 specifies security requirements for physically unclonable functions (PUFs). It defines what properties PUFs must exhibit - at the level of a single instance and of batches - to be used safely in cryptographic modules and security systems. The standard describes PUF output properties, tamper‑resistance and unclonability, typical PUF use cases (security parameter generation, device identification and device authentication) and how security requirements map to those use cases. Random number generation from PUFs is explicitly out of scope.
Key topics and technical requirements
- Output properties: requirements for steadiness, randomness and uniqueness of PUF responses; concepts such as intra‑Hamming distance (intra‑HD) and inter‑Hamming distance (inter‑HD) are used to quantify reliability and distinctness.
- Unclonability: both mathematical unclonability (resistance to modeling and prediction) and physical unclonability (resistance to physical copying or reproduction).
- Tamper‑resistance: expectations for protection against invasive and non‑invasive attacks, side‑channel analysis and fault injection that could recover or influence PUF outputs.
- PUF interface and building blocks: security considerations for challenge/response interfaces, no‑challenge PUFs, and integration with error‑correction (e.g., fuzzy extractors) to mitigate noise in raw PUF outputs.
- Performance metrics: false acceptance rate (FAR) and false rejection rate (FRR) as measures of inter/intra variability and decision thresholds.
- System‑level view: guidance on evaluating PUFs in context (device life‑cycle, supply chain, and attack surface) and mapping requirements to specific use cases.
- Classification and implementations: informative annexes cover PUF types, example implementations, and PUF life‑cycle considerations.
Applications
ISO/IEC 20897-1 is intended for use where PUFs generate non‑stored cryptographic parameters or serve as device fingerprints. Typical applications include:
- Security parameter generation (keys, nonces, seeds) without storing secrets in non‑volatile memory.
- Device identification for asset tracking and provisioning.
- Device authentication in IoT, secure elements and embedded systems.
The standard helps stakeholders specify, evaluate and communicate PUF security properties during procurement, development and certification.
Who should use this standard
- Cryptographic module designers and integrators
- Silicon and device manufacturers implementing PUFs
- Security evaluators and test laboratories
- Procurement officers specifying PUF‑equipped products
- IoT and embedded system architects seeking hardware-based key management
Related standards
- ISO/IEC 19790 - Security requirements for cryptographic modules (context for PUF use in modules)
- ISO/IEC 18031 - Random bit generation (referenced; RNG via PUFs is out of scope here)
ISO/IEC 20897-1:2020 guides both vendors and buyers to specify and evaluate robust PUF implementations, improving tamper‑resistance and unclonability in modern security architectures.